text: // SPDX-License-Identifier: GPL-2.0+
  /*
   * ipmi_msghandler.c
   *
   * Incoming and outgoing message routing for an IPMI interface.
   *
   * Author: MontaVista Software, Inc.
   *         Corey Minyard <minyard@mvista.com>
   *         source@mvista.com
   *
   * Copyright 2002 MontaVista Software Inc.
   */
  
  #define pr_fmt(fmt) "%s" fmt, "IPMI message handler: "
  #define dev_fmt pr_fmt
  
  #include <linux/module.h>
  #include <linux/errno.h>
  #include <linux/poll.h>
  #include <linux/sched.h>
  #include <linux/seq_file.h>
  #include <linux/spinlock.h>
  #include <linux/mutex.h>
  #include <linux/slab.h>
  #include <linux/ipmi.h>
  #include <linux/ipmi_smi.h>
  #include <linux/notifier.h>
  #include <linux/init.h>
  #include <linux/proc_fs.h>
  #include <linux/rcupdate.h>
  #include <linux/interrupt.h>
  #include <linux/moduleparam.h>
  #include <linux/workqueue.h>
  #include <linux/uuid.h>
  #include <linux/nospec.h>
  
  #define IPMI_DRIVER_VERSION "39.2"
  
  static struct ipmi_recv_msg *ipmi_alloc_recv_msg(void);
  static int ipmi_init_msghandler(void);
  static void smi_recv_tasklet(unsigned long);
  static void handle_new_recv_msgs(struct ipmi_smi *intf);
  static void need_waiter(struct ipmi_smi *intf);
  static int handle_one_recv_msg(struct ipmi_smi *intf,
  			       struct ipmi_smi_msg *msg);
  
  #ifdef DEBUG
  static void ipmi_debug_msg(const char *title, unsigned char *data,
  			   unsigned int len)
  {
  	int i, pos;
  	char buf[100];
  
  	pos = snprintf(buf, sizeof(buf), "%s: ", title);
  	for (i = 0; i < len; i++)
  		pos += snprintf(buf + pos, sizeof(buf) - pos,
  				" %2.2x", data[i]);
  	pr_debug("%s\n", buf);
  }
  #else
  static void ipmi_debug_msg(const char *title, unsigned char *data,
  			   unsigned int len)
  { }
  #endif
  
  static bool initialized;
  static bool drvregistered;
  
  enum ipmi_panic_event_op {
  	IPMI_SEND_PANIC_EVENT_NONE,
  	IPMI_SEND_PANIC_EVENT,
  	IPMI_SEND_PANIC_EVENT_STRING
  };
  #ifdef CONFIG_IPMI_PANIC_STRING
  #define IPMI_PANIC_DEFAULT IPMI_SEND_PANIC_EVENT_STRING
  #elif defined(CONFIG_IPMI_PANIC_EVENT)
  #define IPMI_PANIC_DEFAULT IPMI_SEND_PANIC_EVENT
  #else
  #define IPMI_PANIC_DEFAULT IPMI_SEND_PANIC_EVENT_NONE
  #endif
  static enum ipmi_panic_event_op ipmi_send_panic_event = IPMI_PANIC_DEFAULT;
  
  static int panic_op_write_handler(const char *val,
  				  const struct kernel_param *kp)
  {
  	char valcp[16];
  	char *s;
  
  	strncpy(valcp, val, 15);
  	valcp[15] = '\0';
  
  	s = strstrip(valcp);
  
  	if (strcmp(s, "none") == 0)
  		ipmi_send_panic_event = IPMI_SEND_PANIC_EVENT_NONE;
  	else if (strcmp(s, "event") == 0)
  		ipmi_send_panic_event = IPMI_SEND_PANIC_EVENT;
  	else if (strcmp(s, "string") == 0)
  		ipmi_send_panic_event = IPMI_SEND_PANIC_EVENT_STRING;
  	else
  		return -EINVAL;
  
  	return 0;
  }
  
  static int panic_op_read_handler(char *buffer, const struct kernel_param *kp)
  {
  	switch (ipmi_send_panic_event) {
  	case IPMI_SEND_PANIC_EVENT_NONE:
  		strcpy(buffer, "none");
  		break;
  
  	case IPMI_SEND_PANIC_EVENT:
  		strcpy(buffer, "event");
  		break;
  
  	case IPMI_SEND_PANIC_EVENT_STRING:
  		strcpy(buffer, "string");
  		break;
  
  	default:
  		strcpy(buffer, "???");
  		break;
  	}
  
  	return strlen(buffer);
  }
  
  static const struct kernel_param_ops panic_op_ops = {
  	.set = panic_op_write_handler,
  	.get = panic_op_read_handler
  };
  module_param_cb(panic_op, &panic_op_ops, NULL, 0600);
  MODULE_PARM_DESC(panic_op, "Sets if the IPMI driver will attempt to store panic information in the event log in the event of a panic.  Set to 'none' for no, 'event' for a single event, or 'string' for a generic event and the panic string in IPMI OEM events.");
  
  
  #define MAX_EVENTS_IN_QUEUE	25
  
  /* Remain in auto-maintenance mode for this amount of time (in ms). */
  static unsigned long maintenance_mode_timeout_ms = 30000;
  module_param(maintenance_mode_timeout_ms, ulong, 0644);
  MODULE_PARM_DESC(maintenance_mode_timeout_ms,
  		 "The time (milliseconds) after the last maintenance message that the connection stays in maintenance mode.");
  
  /*
   * Don't let a message sit in a queue forever, always time it with at lest
   * the max message timer.  This is in milliseconds.
   */
  #define MAX_MSG_TIMEOUT		60000
  
  /*
   * Timeout times below are in milliseconds, and are done off a 1
   * second timer.  So setting the value to 1000 would mean anything
   * between 0 and 1000ms.  So really the only reasonable minimum
   * setting it 2000ms, which is between 1 and 2 seconds.
   */
  
  /* The default timeout for message retries. */
  static unsigned long default_retry_ms = 2000;
  module_param(default_retry_ms, ulong, 0644);
  MODULE_PARM_DESC(default_retry_ms,
  		 "The time (milliseconds) between retry sends");
  
  /* The default timeout for maintenance mode message retries. */
  static unsigned long default_maintenance_retry_ms = 3000;
  module_param(default_maintenance_retry_ms, ulong, 0644);
  MODULE_PARM_DESC(default_maintenance_retry_ms,
  		 "The time (milliseconds) between retry sends in maintenance mode");
  
  /* The default maximum number of retries */
  static unsigned int default_max_retries = 4;
  module_param(default_max_retries, uint, 0644);
  MODULE_PARM_DESC(default_max_retries,
  		 "The time (milliseconds) between retry sends in maintenance mode");
  
  /* Call every ~1000 ms. */
  #define IPMI_TIMEOUT_TIME	1000
  
  /* How many jiffies does it take to get to the timeout time. */
  #define IPMI_TIMEOUT_JIFFIES	((IPMI_TIMEOUT_TIME * HZ) / 1000)
  
  /*
   * Request events from the queue every second (this is the number of
   * IPMI_TIMEOUT_TIMES between event requests).  Hopefully, in the
   * future, IPMI will add a way to know immediately if an event is in
   * the queue and this silliness can go away.
   */
  #define IPMI_REQUEST_EV_TIME	(1000 / (IPMI_TIMEOUT_TIME))
  
  /* How long should we cache dynamic device IDs? */
  #define IPMI_DYN_DEV_ID_EXPIRY	(10 * HZ)
  
  /*
   * The main "user" data structure.
   */
  struct ipmi_user {
  	struct list_head link;
  
  	/*
  	 * Set to NULL when the user is destroyed, a pointer to myself
  	 * so srcu_dereference can be used on it.
  	 */
  	struct ipmi_user *self;
  	struct srcu_struct release_barrier;
  
  	struct kref refcount;
  
  	/* The upper layer that handles receive messages. */
  	const struct ipmi_user_hndl *handler;
  	void             *handler_data;
  
  	/* The interface this user is bound to. */
  	struct ipmi_smi *intf;
  
  	/* Does this interface receive IPMI events? */
  	bool gets_events;
  
  	/* Free must run in process context for RCU cleanup. */
  	struct work_struct remove_work;
  };
  
  static struct ipmi_user *acquire_ipmi_user(struct ipmi_user *user, int *index)
  	__acquires(user->release_barrier)
  {
  	struct ipmi_user *ruser;
  
  	*index = srcu_read_lock(&user->release_barrier);
  	ruser = srcu_dereference(user->self, &user->release_barrier);
  	if (!ruser)
  		srcu_read_unlock(&user->release_barrier, *index);
  	return ruser;
  }
  
  static void release_ipmi_user(struct ipmi_user *user, int index)
  {
  	srcu_read_unlock(&user->release_barrier, index);
  }
  
  struct cmd_rcvr {
  	struct list_head link;
  
  	struct ipmi_user *user;
  	unsigned char netfn;
  	unsigned char cmd;
  	unsigned int  chans;
  
  	/*
  	 * This is used to form a linked lised during mass deletion.
  	 * Since this is in an RCU list, we cannot use the link above
  	 * or change any data until the RCU period completes.  So we
  	 * use this next variable during mass deletion so we can have
  	 * a list and don't have to wait and restart the search on
  	 * every individual deletion of a command.
  	 */
  	struct cmd_rcvr *next;
  };
  
  struct seq_table {
  	unsigned int         inuse : 1;
  	unsigned int         broadcast : 1;
  
  	unsigned long        timeout;
  	unsigned long        orig_timeout;
  	unsigned int         retries_left;
  
  	/*
  	 * To verify on an incoming send message response that this is
  	 * the message that the response is for, we keep a sequence id
  	 * and increment it every time we send a message.
  	 */
  	long                 seqid;
  
  	/*
  	 * This is held so we can properly respond to the message on a
  	 * timeout, and it is used to hold the temporary data for
  	 * retransmission, too.
  	 */
  	struct ipmi_recv_msg *recv_msg;
  };
  
  /*
   * Store the information in a msgid (long) to allow us to find a
   * sequence table entry from the msgid.
   */
  #define STORE_SEQ_IN_MSGID(seq, seqid) \
  	((((seq) & 0x3f) << 26) | ((seqid) & 0x3ffffff))
  
  #define GET_SEQ_FROM_MSGID(msgid, seq, seqid) \
  	do {								\
  		seq = (((msgid) >> 26) & 0x3f);				\
  		seqid = ((msgid) & 0x3ffffff);				\
  	} while (0)
  
  #define NEXT_SEQID(seqid) (((seqid) + 1) & 0x3ffffff)
  
  #define IPMI_MAX_CHANNELS       16
  struct ipmi_channel {
  	unsigned char medium;
  	unsigned char protocol;
  };
  
  struct ipmi_channel_set {
  	struct ipmi_channel c[IPMI_MAX_CHANNELS];
  };
  
  struct ipmi_my_addrinfo {
  	/*
  	 * My slave address.  This is initialized to IPMI_BMC_SLAVE_ADDR,
  	 * but may be changed by the user.
  	 */
  	unsigned char address;
  
  	/*
  	 * My LUN.  This should generally stay the SMS LUN, but just in
  	 * case...
  	 */
  	unsigned char lun;
  };
  
  /*
   * Note that the product id, manufacturer id, guid, and device id are
   * immutable in this structure, so dyn_mutex is not required for
   * accessing those.  If those change on a BMC, a new BMC is allocated.
   */
  struct bmc_device {
  	struct platform_device pdev;
  	struct list_head       intfs; /* Interfaces on this BMC. */
  	struct ipmi_device_id  id;
  	struct ipmi_device_id  fetch_id;
  	int                    dyn_id_set;
  	unsigned long          dyn_id_expiry;
  	struct mutex           dyn_mutex; /* Protects id, intfs, & dyn* */
  	guid_t                 guid;
  	guid_t                 fetch_guid;
  	int                    dyn_guid_set;
  	struct kref	       usecount;
  	struct work_struct     remove_work;
  };
  #define to_bmc_device(x) container_of((x), struct bmc_device, pdev.dev)
  
  static int bmc_get_device_id(struct ipmi_smi *intf, struct bmc_device *bmc,
  			     struct ipmi_device_id *id,
  			     bool *guid_set, guid_t *guid);
  
  /*
   * Various statistics for IPMI, these index stats[] in the ipmi_smi
   * structure.
   */
  enum ipmi_stat_indexes {
  	/* Commands we got from the user that were invalid. */
  	IPMI_STAT_sent_invalid_commands = 0,
  
  	/* Commands we sent to the MC. */
  	IPMI_STAT_sent_local_commands,
  
  	/* Responses from the MC that were delivered to a user. */
  	IPMI_STAT_handled_local_responses,
  
  	/* Responses from the MC that were not delivered to a user. */
  	IPMI_STAT_unhandled_local_responses,
  
  	/* Commands we sent out to the IPMB bus. */
  	IPMI_STAT_sent_ipmb_commands,
  
  	/* Commands sent on the IPMB that had errors on the SEND CMD */
  	IPMI_STAT_sent_ipmb_command_errs,
  
  	/* Each retransmit increments this count. */
  	IPMI_STAT_retransmitted_ipmb_commands,
  
  	/*
  	 * When a message times out (runs out of retransmits) this is
  	 * incremented.
  	 */
  	IPMI_STAT_timed_out_ipmb_commands,
  
  	/*
  	 * This is like above, but for broadcasts.  Broadcasts are
  	 * *not* included in the above count (they are expected to
  	 * time out).
  	 */
  	IPMI_STAT_timed_out_ipmb_broadcasts,
  
  	/* Responses I have sent to the IPMB bus. */
  	IPMI_STAT_sent_ipmb_responses,
  
  	/* The response was delivered to the user. */
  	IPMI_STAT_handled_ipmb_responses,
  
  	/* The response had invalid data in it. */
  	IPMI_STAT_invalid_ipmb_responses,
  
  	/* The response didn't have anyone waiting for it. */
  	IPMI_STAT_unhandled_ipmb_responses,
  
  	/* Commands we sent out to the IPMB bus. */
  	IPMI_STAT_sent_lan_commands,
  
  	/* Commands sent on the IPMB that had errors on the SEND CMD */
  	IPMI_STAT_sent_lan_command_errs,
  
  	/* Each retransmit increments this count. */
  	IPMI_STAT_retransmitted_lan_commands,
  
  	/*
  	 * When a message times out (runs out of retransmits) this is
  	 * incremented.
  	 */
  	IPMI_STAT_timed_out_lan_commands,
  
  	/* Responses I have sent to the IPMB bus. */
  	IPMI_STAT_sent_lan_responses,
  
  	/* The response was delivered to the user. */
  	IPMI_STAT_handled_lan_responses,
  
  	/* The response had invalid data in it. */
  	IPMI_STAT_invalid_lan_responses,
  
  	/* The response didn't have anyone waiting for it. */
  	IPMI_STAT_unhandled_lan_responses,
  
  	/* The command was delivered to the user. */
  	IPMI_STAT_handled_commands,
  
  	/* The command had invalid data in it. */
  	IPMI_STAT_invalid_commands,
  
  	/* The command didn't have anyone waiting for it. */
  	IPMI_STAT_unhandled_commands,
  
  	/* Invalid data in an event. */
  	IPMI_STAT_invalid_events,
  
  	/* Events that were received with the proper format. */
  	IPMI_STAT_events,
  
  	/* Retransmissions on IPMB that failed. */
  	IPMI_STAT_dropped_rexmit_ipmb_commands,
  
  	/* Retransmissions on LAN that failed. */
  	IPMI_STAT_dropped_rexmit_lan_commands,
  
  	/* This *must* remain last, add new values above this. */
  	IPMI_NUM_STATS
  };
  
  
  #define IPMI_IPMB_NUM_SEQ	64
  struct ipmi_smi {
  	/* What interface number are we? */
  	int intf_num;
  
  	struct kref refcount;
  
  	/* Set when the interface is being unregistered. */
  	bool in_shutdown;
  
  	/* Used for a list of interfaces. */
  	struct list_head link;
  
  	/*
  	 * The list of upper layers that are using me.  seq_lock write
  	 * protects this.  Read protection is with srcu.
  	 */
  	struct list_head users;
  	struct srcu_struct users_srcu;
  
  	/* Used for wake ups at startup. */
  	wait_queue_head_t waitq;
  
  	/*
  	 * Prevents the interface from being unregistered when the
  	 * interface is used by being looked up through the BMC
  	 * structure.
  	 */
  	struct mutex bmc_reg_mutex;
  
  	struct bmc_device tmp_bmc;
  	struct bmc_device *bmc;
  	bool bmc_registered;
  	struct list_head bmc_link;
  	char *my_dev_name;
  	bool in_bmc_register;  /* Handle recursive situations.  Yuck. */
  	struct work_struct bmc_reg_work;
  
  	const struct ipmi_smi_handlers *handlers;
  	void                     *send_info;
  
  	/* Driver-model device for the system interface. */
  	struct device          *si_dev;
  
  	/*
  	 * A table of sequence numbers for this interface.  We use the
  	 * sequence numbers for IPMB messages that go out of the
  	 * interface to match them up with their responses.  A routine
  	 * is called periodically to time the items in this list.
  	 */
  	spinlock_t       seq_lock;
  	struct seq_table seq_table[IPMI_IPMB_NUM_SEQ];
  	int curr_seq;
  
  	/*
  	 * Messages queued for delivery.  If delivery fails (out of memory
  	 * for instance), They will stay in here to be processed later in a
  	 * periodic timer interrupt.  The tasklet is for handling received
  	 * messages directly from the handler.
  	 */
  	spinlock_t       waiting_rcv_msgs_lock;
  	struct list_head waiting_rcv_msgs;
  	atomic_t	 watchdog_pretimeouts_to_deliver;
  	struct tasklet_struct recv_tasklet;
  
  	spinlock_t             xmit_msgs_lock;
  	struct list_head       xmit_msgs;
  	struct ipmi_smi_msg    *curr_msg;
  	struct list_head       hp_xmit_msgs;
  
  	/*
  	 * The list of command receivers that are registered for commands
  	 * on this interface.
  	 */
  	struct mutex     cmd_rcvrs_mutex;
  	struct list_head cmd_rcvrs;
  
  	/*
  	 * Events that were queues because no one was there to receive
  	 * them.
  	 */
  	spinlock_t       events_lock; /* For dealing with event stuff. */
  	struct list_head waiting_events;
  	unsigned int     waiting_events_count; /* How many events in queue? */
  	char             delivering_events;
  	char             event_msg_printed;
  
  	/* How many users are waiting for events? */
  	atomic_t         event_waiters;
  	unsigned int     ticks_to_req_ev;
  
  	spinlock_t       watch_lock; /* For dealing with watch stuff below. */
  
  	/* How many users are waiting for commands? */
  	unsigned int     command_waiters;
  
  	/* How many users are waiting for watchdogs? */
  	unsigned int     watchdog_waiters;
  
  	/* How many users are waiting for message responses? */
  	unsigned int     response_waiters;
  
  	/*
  	 * Tells what the lower layer has last been asked to watch for,
  	 * messages and/or watchdogs.  Protected by watch_lock.
  	 */
  	unsigned int     last_watch_mask;
  
  	/*
  	 * The event receiver for my BMC, only really used at panic
  	 * shutdown as a place to store this.
  	 */
  	unsigned char event_receiver;
  	unsigned char event_receiver_lun;
  	unsigned char local_sel_device;
  	unsigned char local_event_generator;
  
  	/* For handling of maintenance mode. */
  	int maintenance_mode;
  	bool maintenance_mode_enable;
  	int auto_maintenance_timeout;
  	spinlock_t maintenance_mode_lock; /* Used in a timer... */
  
  	/*
  	 * If we are doing maintenance on something on IPMB, extend
  	 * the timeout time to avoid timeouts writing firmware and
  	 * such.
  	 */
  	int ipmb_maintenance_mode_timeout;
  
  	/*
  	 * A cheap hack, if this is non-null and a message to an
  	 * interface comes in with a NULL user, call this routine with
  	 * it.  Note that the message will still be freed by the
  	 * caller.  This only works on the system interface.
  	 *
  	 * Protected by bmc_reg_mutex.
  	 */
  	void (*null_user_handler)(struct ipmi_smi *intf,
  				  struct ipmi_recv_msg *msg);
  
  	/*
  	 * When we are scanning the channels for an SMI, this will
  	 * tell which channel we are scanning.
  	 */
  	int curr_channel;
  
  	/* Channel information */
  	struct ipmi_channel_set *channel_list;
  	unsigned int curr_working_cset; /* First index into the following. */
  	struct ipmi_channel_set wchannels[2];
  	struct ipmi_my_addrinfo addrinfo[IPMI_MAX_CHANNELS];
  	bool channels_ready;
  
  	atomic_t stats[IPMI_NUM_STATS];
  
  	/*
  	 * run_to_completion duplicate of smb_info, smi_info
  	 * and ipmi_serial_info structures. Used to decrease numbers of
  	 * parameters passed by "low" level IPMI code.
  	 */
  	int run_to_completion;
  };
  #define to_si_intf_from_dev(device) container_of(device, struct ipmi_smi, dev)
  
  static void __get_guid(struct ipmi_smi *intf);
  static void __ipmi_bmc_unregister(struct ipmi_smi *intf);
  static int __ipmi_bmc_register(struct ipmi_smi *intf,
  			       struct ipmi_device_id *id,
  			       bool guid_set, guid_t *guid, int intf_num);
  static int __scan_channels(struct ipmi_smi *intf, struct ipmi_device_id *id);
  
  
  /**
   * The driver model view of the IPMI messaging driver.
   */
  static struct platform_driver ipmidriver = {
  	.driver = {
  		.name = "ipmi",
  		.bus = &platform_bus_type
  	}
  };
  /*
   * This mutex keeps us from adding the same BMC twice.
   */
  static DEFINE_MUTEX(ipmidriver_mutex);
  
  static LIST_HEAD(ipmi_interfaces);
  static DEFINE_MUTEX(ipmi_interfaces_mutex);
  static struct srcu_struct ipmi_interfaces_srcu;
  
  /*
   * List of watchers that want to know when smi's are added and deleted.
   */
  static LIST_HEAD(smi_watchers);
  static DEFINE_MUTEX(smi_watchers_mutex);
  
  #define ipmi_inc_stat(intf, stat) \
  	atomic_inc(&(intf)->stats[IPMI_STAT_ ## stat])
  #define ipmi_get_stat(intf, stat) \
  	((unsigned int) atomic_read(&(intf)->stats[IPMI_STAT_ ## stat]))
  
  static const char * const addr_src_to_str[] = {
  	"invalid", "hotmod", "hardcoded", "SPMI", "ACPI", "SMBIOS", "PCI",
  	"device-tree", "platform"
  };
  
  const char *ipmi_addr_src_to_str(enum ipmi_addr_src src)
  {
  	if (src >= SI_LAST)
  		src = 0; /* Invalid */
  	return addr_src_to_str[src];
  }
  EXPORT_SYMBOL(ipmi_addr_src_to_str);
  
  static int is_lan_addr(struct ipmi_addr *addr)
  {
  	return addr->addr_type == IPMI_LAN_ADDR_TYPE;
  }
  
  static int is_ipmb_addr(struct ipmi_addr *addr)
  {
  	return addr->addr_type == IPMI_IPMB_ADDR_TYPE;
  }
  
  static int is_ipmb_bcast_addr(struct ipmi_addr *addr)
  {
  	return addr->addr_type == IPMI_IPMB_BROADCAST_ADDR_TYPE;
  }
  
  static void free_recv_msg_list(struct list_head *q)
  {
  	struct ipmi_recv_msg *msg, *msg2;
  
  	list_for_each_entry_safe(msg, msg2, q, link) {
  		list_del(&msg->link);
  		ipmi_free_recv_msg(msg);
  	}
  }
  
  static void free_smi_msg_list(struct list_head *q)
  {
  	struct ipmi_smi_msg *msg, *msg2;
  
  	list_for_each_entry_safe(msg, msg2, q, link) {
  		list_del(&msg->link);
  		ipmi_free_smi_msg(msg);
  	}
  }
  
  static void clean_up_interface_data(struct ipmi_smi *intf)
  {
  	int              i;
  	struct cmd_rcvr  *rcvr, *rcvr2;
  	struct list_head list;
  
  	tasklet_kill(&intf->recv_tasklet);
  
  	free_smi_msg_list(&intf->waiting_rcv_msgs);
  	free_recv_msg_list(&intf->waiting_events);
  
  	/*
  	 * Wholesale remove all the entries from the list in the
  	 * interface and wait for RCU to know that none are in use.
  	 */
  	mutex_lock(&intf->cmd_rcvrs_mutex);
  	INIT_LIST_HEAD(&list);
  	list_splice_init_rcu(&intf->cmd_rcvrs, &list, synchronize_rcu);
  	mutex_unlock(&intf->cmd_rcvrs_mutex);
  
  	list_for_each_entry_safe(rcvr, rcvr2, &list, link)
  		kfree(rcvr);
  
  	for (i = 0; i < IPMI_IPMB_NUM_SEQ; i++) {
  		if ((intf->seq_table[i].inuse)
  					&& (intf->seq_table[i].recv_msg))
  			ipmi_free_recv_msg(intf->seq_table[i].recv_msg);
  	}
  }
  
  static void intf_free(struct kref *ref)
  {
  	struct ipmi_smi *intf = container_of(ref, struct ipmi_smi, refcount);
  
  	clean_up_interface_data(intf);
  	kfree(intf);
  }
  
  struct watcher_entry {
  	int              intf_num;
  	struct ipmi_smi  *intf;
  	struct list_head link;
  };
  
  int ipmi_smi_watcher_register(struct ipmi_smi_watcher *watcher)
  {
  	struct ipmi_smi *intf;
  	int index, rv;
  
  	/*
  	 * Make sure the driver is actually initialized, this handles
  	 * problems with initialization order.
  	 */
  	rv = ipmi_init_msghandler();
  	if (rv)
  		return rv;
  
  	mutex_lock(&smi_watchers_mutex);
  
  	list_add(&watcher->link, &smi_watchers);
  
  	index = srcu_read_lock(&ipmi_interfaces_srcu);
  	list_for_each_entry_rcu(intf, &ipmi_interfaces, link) {
  		int intf_num = READ_ONCE(intf->intf_num);
  
  		if (intf_num == -1)
  			continue;
  		watcher->new_smi(intf_num, intf->si_dev);
  	}
  	srcu_read_unlock(&ipmi_interfaces_srcu, index);
  
  	mutex_unlock(&smi_watchers_mutex);
  
  	return 0;
  }
  EXPORT_SYMBOL(ipmi_smi_watcher_register);
  
  int ipmi_smi_watcher_unregister(struct ipmi_smi_watcher *watcher)
  {
  	mutex_lock(&smi_watchers_mutex);
  	list_del(&watcher->link);
  	mutex_unlock(&smi_watchers_mutex);
  	return 0;
  }
  EXPORT_SYMBOL(ipmi_smi_watcher_unregister);
  
  /*
   * Must be called with smi_watchers_mutex held.
   */
  static void
  call_smi_watchers(int i, struct device *dev)
  {
  	struct ipmi_smi_watcher *w;
  
  	mutex_lock(&smi_watchers_mutex);
  	list_for_each_entry(w, &smi_watchers, link) {
  		if (try_module_get(w->owner)) {
  			w->new_smi(i, dev);
  			module_put(w->owner);
  		}
  	}
  	mutex_unlock(&smi_watchers_mutex);
  }
  
  static int
  ipmi_addr_equal(struct ipmi_addr *addr1, struct ipmi_addr *addr2)
  {
  	if (addr1->addr_type != addr2->addr_type)
  		return 0;
  
  	if (addr1->channel != addr2->channel)
  		return 0;
  
  	if (addr1->addr_type == IPMI_SYSTEM_INTERFACE_ADDR_TYPE) {
  		struct ipmi_system_interface_addr *smi_addr1
  		    = (struct ipmi_system_interface_addr *) addr1;
  		struct ipmi_system_interface_addr *smi_addr2
  		    = (struct ipmi_system_interface_addr *) addr2;
  		return (smi_addr1->lun == smi_addr2->lun);
  	}
  
  	if (is_ipmb_addr(addr1) || is_ipmb_bcast_addr(addr1)) {
  		struct ipmi_ipmb_addr *ipmb_addr1
  		    = (struct ipmi_ipmb_addr *) addr1;
  		struct ipmi_ipmb_addr *ipmb_addr2
  		    = (struct ipmi_ipmb_addr *) addr2;
  
  		return ((ipmb_addr1->slave_addr == ipmb_addr2->slave_addr)
  			&& (ipmb_addr1->lun == ipmb_addr2->lun));
  	}
  
  	if (is_lan_addr(addr1)) {
  		struct ipmi_lan_addr *lan_addr1
  			= (struct ipmi_lan_addr *) addr1;
  		struct ipmi_lan_addr *lan_addr2
  		    = (struct ipmi_lan_addr *) addr2;
  
  		return ((lan_addr1->remote_SWID == lan_addr2->remote_SWID)
  			&& (lan_addr1->local_SWID == lan_addr2->local_SWID)
  			&& (lan_addr1->session_handle
  			    == lan_addr2->session_handle)
  			&& (lan_addr1->lun == lan_addr2->lun));
  	}
  
  	return 1;
  }
  
  int ipmi_validate_addr(struct ipmi_addr *addr, int len)
  {
  	if (len < sizeof(struct ipmi_system_interface_addr))
  		return -EINVAL;
  
  	if (addr->addr_type == IPMI_SYSTEM_INTERFACE_ADDR_TYPE) {
  		if (addr->channel != IPMI_BMC_CHANNEL)
  			return -EINVAL;
  		return 0;
  	}
  
  	if ((addr->channel == IPMI_BMC_CHANNEL)
  	    || (addr->channel >= IPMI_MAX_CHANNELS)
  	    || (addr->channel < 0))
  		return -EINVAL;
  
  	if (is_ipmb_addr(addr) || is_ipmb_bcast_addr(addr)) {
  		if (len < sizeof(struct ipmi_ipmb_addr))
  			return -EINVAL;
  		return 0;
  	}
  
  	if (is_lan_addr(addr)) {
  		if (len < sizeof(struct ipmi_lan_addr))
  			return -EINVAL;
  		return 0;
  	}
  
  	return -EINVAL;
  }
  EXPORT_SYMBOL(ipmi_validate_addr);
  
  unsigned int ipmi_addr_length(int addr_type)
  {
  	if (addr_type == IPMI_SYSTEM_INTERFACE_ADDR_TYPE)
  		return sizeof(struct ipmi_system_interface_addr);
  
  	if ((addr_type == IPMI_IPMB_ADDR_TYPE)
  			|| (addr_type == IPMI_IPMB_BROADCAST_ADDR_TYPE))
  		return sizeof(struct ipmi_ipmb_addr);
  
  	if (addr_type == IPMI_LAN_ADDR_TYPE)
  		return sizeof(struct ipmi_lan_addr);
  
  	return 0;
  }
  EXPORT_SYMBOL(ipmi_addr_length);
  
  static int deliver_response(struct ipmi_smi *intf, struct ipmi_recv_msg *msg)
  {
  	int rv = 0;
  
  	if (!msg->user) {
  		/* Special handling for NULL users. */
  		if (intf->null_user_handler) {
  			intf->null_user_handler(intf, msg);
  		} else {
  			/* No handler, so give up. */
  			rv = -EINVAL;
  		}
  		ipmi_free_recv_msg(msg);
  	} else if (!oops_in_progress) {
  		/*
  		 * If we are running in the panic context, calling the
  		 * receive handler doesn't much meaning and has a deadlock
  		 * risk.  At this moment, simply skip it in that case.
  		 */
  		int index;
  		struct ipmi_user *user = acquire_ipmi_user(msg->user, &index);
  
  		if (user) {
  			user->handler->ipmi_recv_hndl(msg, user->handler_data);
  			release_ipmi_user(user, index);
  		} else {
  			/* User went away, give up. */
  			ipmi_free_recv_msg(msg);
  			rv = -EINVAL;
  		}
  	}
  
  	return rv;
  }
  
  static void deliver_local_response(struct ipmi_smi *intf,
  				   struct ipmi_recv_msg *msg)
  {
  	if (deliver_response(intf, msg))
  		ipmi_inc_stat(intf, unhandled_local_responses);
  	else
  		ipmi_inc_stat(intf, handled_local_responses);
  }
  
  static void deliver_err_response(struct ipmi_smi *intf,
  				 struct ipmi_recv_msg *msg, int err)
  {
  	msg->recv_type = IPMI_RESPONSE_RECV_TYPE;
  	msg->msg_data[0] = err;
  	msg->msg.netfn |= 1; /* Convert to a response. */
  	msg->msg.data_len = 1;
  	msg->msg.data = msg->msg_data;
  	deliver_local_response(intf, msg);
  }
  
  static void smi_add_watch(struct ipmi_smi *intf, unsigned int flags)
  {
  	unsigned long iflags;
  
  	if (!intf->handlers->set_need_watch)
  		return;
  
  	spin_lock_irqsave(&intf->watch_lock, iflags);
  	if (flags & IPMI_WATCH_MASK_CHECK_MESSAGES)
  		intf->response_waiters++;
  
  	if (flags & IPMI_WATCH_MASK_CHECK_WATCHDOG)
  		intf->watchdog_waiters++;
  
  	if (flags & IPMI_WATCH_MASK_CHECK_COMMANDS)
  		intf->command_waiters++;
  
  	if ((intf->last_watch_mask & flags) != flags) {
  		intf->last_watch_mask |= flags;
  		intf->handlers->set_need_watch(intf->send_info,
  					       intf->last_watch_mask);
  	}
  	spin_unlock_irqrestore(&intf->watch_lock, iflags);
  }
  
  static void smi_remove_watch(struct ipmi_smi *intf, unsigned int flags)
  {
  	unsigned long iflags;
  
  	if (!intf->handlers->set_need_watch)
  		return;
  
  	spin_lock_irqsave(&intf->watch_lock, iflags);
  	if (flags & IPMI_WATCH_MASK_CHECK_MESSAGES)
  		intf->response_waiters--;
  
  	if (flags & IPMI_WATCH_MASK_CHECK_WATCHDOG)
  		intf->watchdog_waiters--;
  
  	if (flags & IPMI_WATCH_MASK_CHECK_COMMANDS)
  		intf->command_waiters--;
  
  	flags = 0;
  	if (intf->response_waiters)
  		flags |= IPMI_WATCH_MASK_CHECK_MESSAGES;
  	if (intf->watchdog_waiters)
  		flags |= IPMI_WATCH_MASK_CHECK_WATCHDOG;
  	if (intf->command_waiters)
  		flags |= IPMI_WATCH_MASK_CHECK_COMMANDS;
  
  	if (intf->last_watch_mask != flags) {
  		intf->last_watch_mask = flags;
  		intf->handlers->set_need_watch(intf->send_info,
  					       intf->last_watch_mask);
  	}
  	spin_unlock_irqrestore(&intf->watch_lock, iflags);
  }
  
  /*
   * Find the next sequence number not being used and add the given
   * message with the given timeout to the sequence table.  This must be
   * called with the interface's seq_lock held.
   */
  static int intf_next_seq(struct ipmi_smi      *intf,
  			 struct ipmi_recv_msg *recv_msg,
  			 unsigned long        timeout,
  			 int                  retries,
  			 int                  broadcast,
  			 unsigned char        *seq,
  			 long                 *seqid)
  {
  	int          rv = 0;
  	unsigned int i;
  
  	if (timeout == 0)
  		timeout = default_retry_ms;
  	if (retries < 0)
  		retries = default_max_retries;
  
  	for (i = intf->curr_seq; (i+1)%IPMI_IPMB_NUM_SEQ != intf->curr_seq;
  					i = (i+1)%IPMI_IPMB_NUM_SEQ) {
  		if (!intf->seq_table[i].inuse)
  			break;
  	}
  
  	if (!intf->seq_table[i].inuse) {
  		intf->seq_table[i].recv_msg = recv_msg;
  
  		/*
  		 * Start with the maximum timeout, when the send response
  		 * comes in we will start the real timer.
  		 */
  		intf->seq_table[i].timeout = MAX_MSG_TIMEOUT;
  		intf->seq_table[i].orig_timeout = timeout;
  		intf->seq_table[i].retries_left = retries;
  		intf->seq_table[i].broadcast = broadcast;
  		intf->seq_table[i].inuse = 1;
  		intf->seq_table[i].seqid = NEXT_SEQID(intf->seq_table[i].seqid);
  		*seq = i;
  		*seqid = intf->seq_table[i].seqid;
  		intf->curr_seq = (i+1)%IPMI_IPMB_NUM_SEQ;
  		smi_add_watch(intf, IPMI_WATCH_MASK_CHECK_MESSAGES);
  		need_waiter(intf);
  	} else {
  		rv = -EAGAIN;
  	}
  
  	return rv;
  }
  
  /*
   * Return the receive message for the given sequence number and
   * release the sequence number so it can be reused.  Some other data
   * is passed in to be sure the message matches up correctly (to help
   * guard against message coming in after their timeout and the
   * sequence number being reused).
   */
  static int intf_find_seq(struct ipmi_smi      *intf,
  			 unsigned char        seq,
  			 short                channel,
  			 unsigned char        cmd,
  			 unsigned char        netfn,
  			 struct ipmi_addr     *addr,
  			 struct ipmi_recv_msg **recv_msg)
  {
  	int           rv = -ENODEV;
  	unsigned long flags;
  
  	if (seq >= IPMI_IPMB_NUM_SEQ)
  		return -EINVAL;
  
  	spin_lock_irqsave(&intf->seq_lock, flags);
  	if (intf->seq_table[seq].inuse) {
  		struct ipmi_recv_msg *msg = intf->seq_table[seq].recv_msg;
  
  		if ((msg->addr.channel == channel) && (msg->msg.cmd == cmd)
  				&& (msg->msg.netfn == netfn)
  				&& (ipmi_addr_equal(addr, &msg->addr))) {
  			*recv_msg = msg;
  			intf->seq_table[seq].inuse = 0;
  			smi_remove_watch(intf, IPMI_WATCH_MASK_CHECK_MESSAGES);
  			rv = 0;
  		}
  	}
  	spin_unlock_irqrestore(&intf->seq_lock, flags);
  
  	return rv;
  }
  
  
  /* Start the timer for a specific sequence table entry. */
  static int intf_start_seq_timer(struct ipmi_smi *intf,
  				long       msgid)
  {
  	int           rv = -ENODEV;
  	unsigned long flags;
  	unsigned char seq;
  	unsigned long seqid;
  
  
  	GET_SEQ_FROM_MSGID(msgid, seq, seqid);
  
  	spin_lock_irqsave(&intf->seq_lock, flags);
  	/*
  	 * We do this verification because the user can be deleted
  	 * while a message is outstanding.
  	 */
  	if ((intf->seq_table[seq].inuse)
  				&& (intf->seq_table[seq].seqid == seqid)) {
  		struct seq_table *ent = &intf->seq_table[seq];
  		ent->timeout = ent->orig_timeout;
  		rv = 0;
  	}
  	spin_unlock_irqrestore(&intf->seq_lock, flags);
  
  	return rv;
  }
  
  /* Got an error for the send message for a specific sequence number. */
  static int intf_err_seq(struct ipmi_smi *intf,
  			long         msgid,
  			unsigned int err)
  {
  	int                  rv = -ENODEV;
  	unsigned long        flags;
  	unsigned char        seq;
  	unsigned long        seqid;
  	struct ipmi_recv_msg *msg = NULL;
  
  
  	GET_SEQ_FROM_MSGID(msgid, seq, seqid);
  
  	spin_lock_irqsave(&intf->seq_lock, flags);
  	/*
  	 * We do this verification because the user can be deleted
  	 * while a message is outstanding.
  	 */
  	if ((intf->seq_table[seq].inuse)
  				&& (intf->seq_table[seq].seqid == seqid)) {
  		struct seq_table *ent = &intf->seq_table[seq];
  
  		ent->inuse = 0;
  		smi_remove_watch(intf, IPMI_WATCH_MASK_CHECK_MESSAGES);
  		msg = ent->recv_msg;
  		rv = 0;
  	}
  	spin_unlock_irqrestore(&intf->seq_lock, flags);
  
  	if (msg)
  		deliver_err_response(intf, msg, err);
  
  	return rv;
  }
  
  static void free_user_work(struct work_struct *work)
  {
  	struct ipmi_user *user = container_of(work, struct ipmi_user,
  					      remove_work);
  
  	cleanup_srcu_struct(&user->release_barrier);
  	kfree(user);
  }
  
  int ipmi_create_user(unsigned int          if_num,
  		     const struct ipmi_user_hndl *handler,
  		     void                  *handler_data,
  		     struct ipmi_user      **user)
  {
  	unsigned long flags;
  	struct ipmi_user *new_user;
  	int           rv, index;
  	struct ipmi_smi *intf;
  
  	/*
  	 * There is no module usecount here, because it's not
  	 * required.  Since this can only be used by and called from
  	 * other modules, they will implicitly use this module, and
  	 * thus this can't be removed unless the other modules are
  	 * removed.
  	 */
  
  	if (handler == NULL)
  		return -EINVAL;
  
  	/*
  	 * Make sure the driver is actually initialized, this handles
  	 * problems with initialization order.
  	 */
  	rv = ipmi_init_msghandler();
  	if (rv)
  		return rv;
  
  	new_user = kmalloc(sizeof(*new_user), GFP_KERNEL);
  	if (!new_user)
  		return -ENOMEM;
  
  	index = srcu_read_lock(&ipmi_interfaces_srcu);
  	list_for_each_entry_rcu(intf, &ipmi_interfaces, link) {
  		if (intf->intf_num == if_num)
  			goto found;
  	}
  	/* Not found, return an error */
  	rv = -EINVAL;
  	goto out_kfree;
  
   found:
  	INIT_WORK(&new_user->remove_work, free_user_work);
  
  	rv = init_srcu_struct(&new_user->release_barrier);
  	if (rv)
  		goto out_kfree;
  
  	/* Note that each existing user holds a refcount to the interface. */
  	kref_get(&intf->refcount);
  
  	kref_init(&new_user->refcount);
  	new_user->handler = handler;
  	new_user->handler_data = handler_data;
  	new_user->intf = intf;
  	new_user->gets_events = false;
  
  	rcu_assign_pointer(new_user->self, new_user);
  	spin_lock_irqsave(&intf->seq_lock, flags);
  	list_add_rcu(&new_user->link, &intf->users);
  	spin_unlock_irqrestore(&intf->seq_lock, flags);
  	if (handler->ipmi_watchdog_pretimeout)
  		/* User wants pretimeouts, so make sure to watch for them. */
  		smi_add_watch(intf, IPMI_WATCH_MASK_CHECK_WATCHDOG);
  	srcu_read_unlock(&ipmi_interfaces_srcu, index);
  	*user = new_user;
  	return 0;
  
  out_kfree:
  	srcu_read_unlock(&ipmi_interfaces_srcu, index);
  	kfree(new_user);
  	return rv;
  }
  EXPORT_SYMBOL(ipmi_create_user);
  
  int ipmi_get_smi_info(int if_num, struct ipmi_smi_info *data)
  {
  	int rv, index;
  	struct ipmi_smi *intf;
  
  	index = srcu_read_lock(&ipmi_interfaces_srcu);
  	list_for_each_entry_rcu(intf, &ipmi_interfaces, link) {
  		if (intf->intf_num == if_num)
  			goto found;
  	}
  	srcu_read_unlock(&ipmi_interfaces_srcu, index);
  
  	/* Not found, return an error */
  	return -EINVAL;
  
  found:
  	if (!intf->handlers->get_smi_info)
  		rv = -ENOTTY;
  	else
  		rv = intf->handlers->get_smi_info(intf->send_info, data);
  	srcu_read_unlock(&ipmi_interfaces_srcu, index);
  
  	return rv;
  }
  EXPORT_SYMBOL(ipmi_get_smi_info);
  
  static void free_user(struct kref *ref)
  {
  	struct ipmi_user *user = container_of(ref, struct ipmi_user, refcount);
  
  	/* SRCU cleanup must happen in task context. */
  	schedule_work(&user->remove_work);
  }
  
  static void _ipmi_destroy_user(struct ipmi_user *user)
  {
  	struct ipmi_smi  *intf = user->intf;
  	int              i;
  	unsigned long    flags;
  	struct cmd_rcvr  *rcvr;
  	struct cmd_rcvr  *rcvrs = NULL;
  
  	if (!acquire_ipmi_user(user, &i)) {
  		/*
  		 * The user has already been cleaned up, just make sure
  		 * nothing is using it and return.
  		 */
  		synchronize_srcu(&user->release_barrier);
  		return;
  	}
  
  	rcu_assign_pointer(user->self, NULL);
  	release_ipmi_user(user, i);
  
  	synchronize_srcu(&user->release_barrier);
  
  	if (user->handler->shutdown)
  		user->handler->shutdown(user->handler_data);
  
  	if (user->handler->ipmi_watchdog_pretimeout)
  		smi_remove_watch(intf, IPMI_WATCH_MASK_CHECK_WATCHDOG);
  
  	if (user->gets_events)
  		atomic_dec(&intf->event_waiters);
  
  	/* Remove the user from the interface's sequence table. */
  	spin_lock_irqsave(&intf->seq_lock, flags);
  	list_del_rcu(&user->link);
  
  	for (i = 0; i < IPMI_IPMB_NUM_SEQ; i++) {
  		if (intf->seq_table[i].inuse
  		    && (intf->seq_table[i].recv_msg->user == user)) {
  			intf->seq_table[i].inuse = 0;
  			smi_remove_watch(intf, IPMI_WATCH_MASK_CHECK_MESSAGES);
  			ipmi_free_recv_msg(intf->seq_table[i].recv_msg);
  		}
  	}
  	spin_unlock_irqrestore(&intf->seq_lock, flags);
  
  	/*
  	 * Remove the user from the command receiver's table.  First
  	 * we build a list of everything (not using the standard link,
  	 * since other things may be using it till we do
  	 * synchronize_srcu()) then free everything in that list.
  	 */
  	mutex_lock(&intf->cmd_rcvrs_mutex);
  	list_for_each_entry_rcu(rcvr, &intf->cmd_rcvrs, link) {
  		if (rcvr->user == user) {
  			list_del_rcu(&rcvr->link);
  			rcvr->next = rcvrs;
  			rcvrs = rcvr;
  		}
  	}
  	mutex_unlock(&intf->cmd_rcvrs_mutex);
  	synchronize_rcu();
  	while (rcvrs) {
  		rcvr = rcvrs;
  		rcvrs = rcvr->next;
  		kfree(rcvr);
  	}
  
  	kref_put(&intf->refcount, intf_free);
  }
  
  int ipmi_destroy_user(struct ipmi_user *user)
  {
  	_ipmi_destroy_user(user);
  
  	kref_put(&user->refcount, free_user);
  
  	return 0;
  }
  EXPORT_SYMBOL(ipmi_destroy_user);
  
  int ipmi_get_version(struct ipmi_user *user,
  		     unsigned char *major,
  		     unsigned char *minor)
  {
  	struct ipmi_device_id id;
  	int rv, index;
  
  	user = acquire_ipmi_user(user, &index);
  	if (!user)
  		return -ENODEV;
  
  	rv = bmc_get_device_id(user->intf, NULL, &id, NULL, NULL);
  	if (!rv) {
  		*major = ipmi_version_major(&id);
  		*minor = ipmi_version_minor(&id);
  	}
  	release_ipmi_user(user, index);
  
  	return rv;
  }
  EXPORT_SYMBOL(ipmi_get_version);
  
  int ipmi_set_my_address(struct ipmi_user *user,
  			unsigned int  channel,
  			unsigned char address)
  {
  	int index, rv = 0;
  
  	user = acquire_ipmi_user(user, &index);
  	if (!user)
  		return -ENODEV;
  
  	if (channel >= IPMI_MAX_CHANNELS) {
  		rv = -EINVAL;
  	} else {
  		channel = array_index_nospec(channel, IPMI_MAX_CHANNELS);
  		user->intf->addrinfo[channel].address = address;
  	}
  	release_ipmi_user(user, index);
  
  	return rv;
  }
  EXPORT_SYMBOL(ipmi_set_my_address);
  
  int ipmi_get_my_address(struct ipmi_user *user,
  			unsigned int  channel,
  			unsigned char *address)
  {
  	int index, rv = 0;
  
  	user = acquire_ipmi_user(user, &index);
  	if (!user)
  		return -ENODEV;
  
  	if (channel >= IPMI_MAX_CHANNELS) {
  		rv = -EINVAL;
  	} else {
  		channel = array_index_nospec(channel, IPMI_MAX_CHANNELS);
  		*address = user->intf->addrinfo[channel].address;
  	}
  	release_ipmi_user(user, index);
  
  	return rv;
  }
  EXPORT_SYMBOL(ipmi_get_my_address);
  
  int ipmi_set_my_LUN(struct ipmi_user *user,
  		    unsigned int  channel,
  		    unsigned char LUN)
  {
  	int index, rv = 0;
  
  	user = acquire_ipmi_user(user, &index);
  	if (!user)
  		return -ENODEV;
  
  	if (channel >= IPMI_MAX_CHANNELS) {
  		rv = -EINVAL;
  	} else {
  		channel = array_index_nospec(channel, IPMI_MAX_CHANNELS);
  		user->intf->addrinfo[channel].lun = LUN & 0x3;
  	}
  	release_ipmi_user(user, index);
  
  	return rv;
  }
  EXPORT_SYMBOL(ipmi_set_my_LUN);
  
  int ipmi_get_my_LUN(struct ipmi_user *user,
  		    unsigned int  channel,
  		    unsigned char *address)
  {
  	int index, rv = 0;
  
  	user = acquire_ipmi_user(user, &index);
  	if (!user)
  		return -ENODEV;
  
  	if (channel >= IPMI_MAX_CHANNELS) {
  		rv = -EINVAL;
  	} else {
  		channel = array_index_nospec(channel, IPMI_MAX_CHANNELS);
  		*address = user->intf->addrinfo[channel].lun;
  	}
  	release_ipmi_user(user, index);
  
  	return rv;
  }
  EXPORT_SYMBOL(ipmi_get_my_LUN);
  
  int ipmi_get_maintenance_mode(struct ipmi_user *user)
  {
  	int mode, index;
  	unsigned long flags;
  
  	user = acquire_ipmi_user(user, &index);
  	if (!user)
  		return -ENODEV;
  
  	spin_lock_irqsave(&user->intf->maintenance_mode_lock, flags);
  	mode = user->intf->maintenance_mode;
  	spin_unlock_irqrestore(&user->intf->maintenance_mode_lock, flags);
  	release_ipmi_user(user, index);
  
  	return mode;
  }
  EXPORT_SYMBOL(ipmi_get_maintenance_mode);
  
  static void maintenance_mode_update(struct ipmi_smi *intf)
  {
  	if (intf->handlers->set_maintenance_mode)
  		intf->handlers->set_maintenance_mode(
  			intf->send_info, intf->maintenance_mode_enable);
  }
  
  int ipmi_set_maintenance_mode(struct ipmi_user *user, int mode)
  {
  	int rv = 0, index;
  	unsigned long flags;
  	struct ipmi_smi *intf = user->intf;
  
  	user = acquire_ipmi_user(user, &index);
  	if (!user)
  		return -ENODEV;
  
  	spin_lock_irqsave(&intf->maintenance_mode_lock, flags);
  	if (intf->maintenance_mode != mode) {
  		switch (mode) {
  		case IPMI_MAINTENANCE_MODE_AUTO:
  			intf->maintenance_mode_enable
  				= (intf->auto_maintenance_timeout > 0);
  			break;
  
  		case IPMI_MAINTENANCE_MODE_OFF:
  			intf->maintenance_mode_enable = false;
  			break;
  
  		case IPMI_MAINTENANCE_MODE_ON:
  			intf->maintenance_mode_enable = true;
  			break;
  
  		default:
  			rv = -EINVAL;
  			goto out_unlock;
  		}
  		intf->maintenance_mode = mode;
  
  		maintenance_mode_update(intf);
  	}
   out_unlock:
  	spin_unlock_irqrestore(&intf->maintenance_mode_lock, flags);
  	release_ipmi_user(user, index);
  
  	return rv;
  }
  EXPORT_SYMBOL(ipmi_set_maintenance_mode);
  
  int ipmi_set_gets_events(struct ipmi_user *user, bool val)
  {
  	unsigned long        flags;
  	struct ipmi_smi      *intf = user->intf;
  	struct ipmi_recv_msg *msg, *msg2;
  	struct list_head     msgs;
  	int index;
  
  	user = acquire_ipmi_user(user, &index);
  	if (!user)
  		return -ENODEV;
  
  	INIT_LIST_HEAD(&msgs);
  
  	spin_lock_irqsave(&intf->events_lock, flags);
  	if (user->gets_events == val)
  		goto out;
  
  	user->gets_events = val;
  
  	if (val) {
  		if (atomic_inc_return(&intf->event_waiters) == 1)
  			need_waiter(intf);
  	} else {
  		atomic_dec(&intf->event_waiters);
  	}
  
  	if (intf->delivering_events)
  		/*
  		 * Another thread is delivering events for this, so
  		 * let it handle any new events.
  		 */
  		goto out;
  
  	/* Deliver any queued events. */
  	while (user->gets_events && !list_empty(&intf->waiting_events)) {
  		list_for_each_entry_safe(msg, msg2, &intf->waiting_events, link)
  			list_move_tail(&msg->link, &msgs);
  		intf->waiting_events_count = 0;
  		if (intf->event_msg_printed) {
  			dev_warn(intf->si_dev, "Event queue no longer full\n");
  			intf->event_msg_printed = 0;
  		}
  
  		intf->delivering_events = 1;
  		spin_unlock_irqrestore(&intf->events_lock, flags);
  
  		list_for_each_entry_safe(msg, msg2, &msgs, link) {
  			msg->user = user;
  			kref_get(&user->refcount);
  			deliver_local_response(intf, msg);
  		}
  
  		spin_lock_irqsave(&intf->events_lock, flags);
  		intf->delivering_events = 0;
  	}
  
   out:
  	spin_unlock_irqrestore(&intf->events_lock, flags);
  	release_ipmi_user(user, index);
  
  	return 0;
  }
  EXPORT_SYMBOL(ipmi_set_gets_events);
  
  static struct cmd_rcvr *find_cmd_rcvr(struct ipmi_smi *intf,
  				      unsigned char netfn,
  				      unsigned char cmd,
  				      unsigned char chan)
  {
  	struct cmd_rcvr *rcvr;
  
  	list_for_each_entry_rcu(rcvr, &intf->cmd_rcvrs, link) {
  		if ((rcvr->netfn == netfn) && (rcvr->cmd == cmd)
  					&& (rcvr->chans & (1 << chan)))
  			return rcvr;
  	}
  	return NULL;
  }
  
  static int is_cmd_rcvr_exclusive(struct ipmi_smi *intf,
  				 unsigned char netfn,
  				 unsigned char cmd,
  				 unsigned int  chans)
  {
  	struct cmd_rcvr *rcvr;
  
  	list_for_each_entry_rcu(rcvr, &intf->cmd_rcvrs, link) {
  		if ((rcvr->netfn == netfn) && (rcvr->cmd == cmd)
  					&& (rcvr->chans & chans))
  			return 0;
  	}
  	return 1;
  }
  
  int ipmi_register_for_cmd(struct ipmi_user *user,
  			  unsigned char netfn,
  			  unsigned char cmd,
  			  unsigned int  chans)
  {
  	struct ipmi_smi *intf = user->intf;
  	struct cmd_rcvr *rcvr;
  	int rv = 0, index;
  
  	user = acquire_ipmi_user(user, &index);
  	if (!user)
  		return -ENODEV;
  
  	rcvr = kmalloc(sizeof(*rcvr), GFP_KERNEL);
  	if (!rcvr) {
  		rv = -ENOMEM;
  		goto out_release;
  	}
  	rcvr->cmd = cmd;
  	rcvr->netfn = netfn;
  	rcvr->chans = chans;
  	rcvr->user = user;
  
  	mutex_lock(&intf->cmd_rcvrs_mutex);
  	/* Make sure the command/netfn is not already registered. */
  	if (!is_cmd_rcvr_exclusive(intf, netfn, cmd, chans)) {
  		rv = -EBUSY;
  		goto out_unlock;
  	}
  
  	smi_add_watch(intf, IPMI_WATCH_MASK_CHECK_COMMANDS);
  
  	list_add_rcu(&rcvr->link, &intf->cmd_rcvrs);
  
  out_unlock:
  	mutex_unlock(&intf->cmd_rcvrs_mutex);
  	if (rv)
  		kfree(rcvr);
  out_release:
  	release_ipmi_user(user, index);
  
  	return rv;
  }
  EXPORT_SYMBOL(ipmi_register_for_cmd);
  
  int ipmi_unregister_for_cmd(struct ipmi_user *user,
  			    unsigned char netfn,
  			    unsigned char cmd,
  			    unsigned int  chans)
  {
  	struct ipmi_smi *intf = user->intf;
  	struct cmd_rcvr *rcvr;
  	struct cmd_rcvr *rcvrs = NULL;
  	int i, rv = -ENOENT, index;
  
  	user = acquire_ipmi_user(user, &index);
  	if (!user)
  		return -ENODEV;
  
  	mutex_lock(&intf->cmd_rcvrs_mutex);
  	for (i = 0; i < IPMI_NUM_CHANNELS; i++) {
  		if (((1 << i) & chans) == 0)
  			continue;
  		rcvr = find_cmd_rcvr(intf, netfn, cmd, i);
  		if (rcvr == NULL)
  			continue;
  		if (rcvr->user == user) {
  			rv = 0;
  			rcvr->chans &= ~chans;
  			if (rcvr->chans == 0) {
  				list_del_rcu(&rcvr->link);
  				rcvr->next = rcvrs;
  				rcvrs = rcvr;
  			}
  		}
  	}
  	mutex_unlock(&intf->cmd_rcvrs_mutex);
  	synchronize_rcu();
  	release_ipmi_user(user, index);
  	while (rcvrs) {
  		smi_remove_watch(intf, IPMI_WATCH_MASK_CHECK_COMMANDS);
  		rcvr = rcvrs;
  		rcvrs = rcvr->next;
  		kfree(rcvr);
  	}
  
  	return rv;
  }
  EXPORT_SYMBOL(ipmi_unregister_for_cmd);
  
  static unsigned char
  ipmb_checksum(unsigned char *data, int size)
  {
  	unsigned char csum = 0;
  
  	for (; size > 0; size--, data++)
  		csum += *data;
  
  	return -csum;
  }
  
  static inline void format_ipmb_msg(struct ipmi_smi_msg   *smi_msg,
  				   struct kernel_ipmi_msg *msg,
  				   struct ipmi_ipmb_addr *ipmb_addr,
  				   long                  msgid,
  				   unsigned char         ipmb_seq,
  				   int                   broadcast,
  				   unsigned char         source_address,
  				   unsigned char         source_lun)
  {
  	int i = broadcast;
  
  	/* Format the IPMB header data. */
  	smi_msg->data[0] = (IPMI_NETFN_APP_REQUEST << 2);
  	smi_msg->data[1] = IPMI_SEND_MSG_CMD;
  	smi_msg->data[2] = ipmb_addr->channel;
  	if (broadcast)
  		smi_msg->data[3] = 0;
  	smi_msg->data[i+3] = ipmb_addr->slave_addr;
  	smi_msg->data[i+4] = (msg->netfn << 2) | (ipmb_addr->lun & 0x3);
  	smi_msg->data[i+5] = ipmb_checksum(&smi_msg->data[i + 3], 2);
  	smi_msg->data[i+6] = source_address;
  	smi_msg->data[i+7] = (ipmb_seq << 2) | source_lun;
  	smi_msg->data[i+8] = msg->cmd;
  
  	/* Now tack on the data to the message. */
  	if (msg->data_len > 0)
  		memcpy(&smi_msg->data[i + 9], msg->data, msg->data_len);
  	smi_msg->data_size = msg->data_len + 9;
  
  	/* Now calculate the checksum and tack it on. */
  	smi_msg->data[i+smi_msg->data_size]
  		= ipmb_checksum(&smi_msg->data[i + 6], smi_msg->data_size - 6);
  
  	/*
  	 * Add on the checksum size and the offset from the
  	 * broadcast.
  	 */
  	smi_msg->data_size += 1 + i;
  
  	smi_msg->msgid = msgid;
  }
  
  static inline void format_lan_msg(struct ipmi_smi_msg   *smi_msg,
  				  struct kernel_ipmi_msg *msg,
  				  struct ipmi_lan_addr  *lan_addr,
  				  long                  msgid,
  				  unsigned char         ipmb_seq,
  				  unsigned char         source_lun)
  {
  	/* Format the IPMB header data. */
  	smi_msg->data[0] = (IPMI_NETFN_APP_REQUEST << 2);
  	smi_msg->data[1] = IPMI_SEND_MSG_CMD;
  	smi_msg->data[2] = lan_addr->channel;
  	smi_msg->data[3] = lan_addr->session_handle;
  	smi_msg->data[4] = lan_addr->remote_SWID;
  	smi_msg->data[5] = (msg->netfn << 2) | (lan_addr->lun & 0x3);
  	smi_msg->data[6] = ipmb_checksum(&smi_msg->data[4], 2);
  	smi_msg->data[7] = lan_addr->local_SWID;
  	smi_msg->data[8] = (ipmb_seq << 2) | source_lun;
  	smi_msg->data[9] = msg->cmd;
  
  	/* Now tack on the data to the message. */
  	if (msg->data_len > 0)
  		memcpy(&smi_msg->data[10], msg->data, msg->data_len);
  	smi_msg->data_size = msg->data_len + 10;
  
  	/* Now calculate the checksum and tack it on. */
  	smi_msg->data[smi_msg->data_size]
  		= ipmb_checksum(&smi_msg->data[7], smi_msg->data_size - 7);
  
  	/*
  	 * Add on the checksum size and the offset from the
  	 * broadcast.
  	 */
  	smi_msg->data_size += 1;
  
  	smi_msg->msgid = msgid;
  }
  
  static struct ipmi_smi_msg *smi_add_send_msg(struct ipmi_smi *intf,
  					     struct ipmi_smi_msg *smi_msg,
  					     int priority)
  {
  	if (intf->curr_msg) {
  		if (priority > 0)
  			list_add_tail(&smi_msg->link, &intf->hp_xmit_msgs);
  		else
  			list_add_tail(&smi_msg->link, &intf->xmit_msgs);
  		smi_msg = NULL;
  	} else {
  		intf->curr_msg = smi_msg;
  	}
  
  	return smi_msg;
  }
  
  static void smi_send(struct ipmi_smi *intf,
  		     const struct ipmi_smi_handlers *handlers,
  		     struct ipmi_smi_msg *smi_msg, int priority)
  {
  	int run_to_completion = intf->run_to_completion;
  	unsigned long flags = 0;
  
  	if (!run_to_completion)
  		spin_lock_irqsave(&intf->xmit_msgs_lock, flags);
  	smi_msg = smi_add_send_msg(intf, smi_msg, priority);
  
  	if (!run_to_completion)
  		spin_unlock_irqrestore(&intf->xmit_msgs_lock, flags);
  
  	if (smi_msg)
  		handlers->sender(intf->send_info, smi_msg);
  }
  
  static bool is_maintenance_mode_cmd(struct kernel_ipmi_msg *msg)
  {
  	return (((msg->netfn == IPMI_NETFN_APP_REQUEST)
  		 && ((msg->cmd == IPMI_COLD_RESET_CMD)
  		     || (msg->cmd == IPMI_WARM_RESET_CMD)))
  		|| (msg->netfn == IPMI_NETFN_FIRMWARE_REQUEST));
  }
  
  static int i_ipmi_req_sysintf(struct ipmi_smi        *intf,
  			      struct ipmi_addr       *addr,
  			      long                   msgid,
  			      struct kernel_ipmi_msg *msg,
  			      struct ipmi_smi_msg    *smi_msg,
  			      struct ipmi_recv_msg   *recv_msg,
  			      int                    retries,
  			      unsigned int           retry_time_ms)
  {
  	struct ipmi_system_interface_addr *smi_addr;
  
  	if (msg->netfn & 1)
  		/* Responses are not allowed to the SMI. */
  		return -EINVAL;
  
  	smi_addr = (struct ipmi_system_interface_addr *) addr;
  	if (smi_addr->lun > 3) {
  		ipmi_inc_stat(intf, sent_invalid_commands);
  		return -EINVAL;
  	}
  
  	memcpy(&recv_msg->addr, smi_addr, sizeof(*smi_addr));
  
  	if ((msg->netfn == IPMI_NETFN_APP_REQUEST)
  	    && ((msg->cmd == IPMI_SEND_MSG_CMD)
  		|| (msg->cmd == IPMI_GET_MSG_CMD)
  		|| (msg->cmd == IPMI_READ_EVENT_MSG_BUFFER_CMD))) {
  		/*
  		 * We don't let the user do these, since we manage
  		 * the sequence numbers.
  		 */
  		ipmi_inc_stat(intf, sent_invalid_commands);
  		return -EINVAL;
  	}
  
  	if (is_maintenance_mode_cmd(msg)) {
  		unsigned long flags;
  
  		spin_lock_irqsave(&intf->maintenance_mode_lock, flags);
  		intf->auto_maintenance_timeout
  			= maintenance_mode_timeout_ms;
  		if (!intf->maintenance_mode
  		    && !intf->maintenance_mode_enable) {
  			intf->maintenance_mode_enable = true;
  			maintenance_mode_update(intf);
  		}
  		spin_unlock_irqrestore(&intf->maintenance_mode_lock,
  				       flags);
  	}
  
  	if (msg->data_len + 2 > IPMI_MAX_MSG_LENGTH) {
  		ipmi_inc_stat(intf, sent_invalid_commands);
  		return -EMSGSIZE;
  	}
  
  	smi_msg->data[0] = (msg->netfn << 2) | (smi_addr->lun & 0x3);
  	smi_msg->data[1] = msg->cmd;
  	smi_msg->msgid = msgid;
  	smi_msg->user_data = recv_msg;
  	if (msg->data_len > 0)
  		memcpy(&smi_msg->data[2], msg->data, msg->data_len);
  	smi_msg->data_size = msg->data_len + 2;
  	ipmi_inc_stat(intf, sent_local_commands);
  
  	return 0;
  }
  
  static int i_ipmi_req_ipmb(struct ipmi_smi        *intf,
  			   struct ipmi_addr       *addr,
  			   long                   msgid,
  			   struct kernel_ipmi_msg *msg,
  			   struct ipmi_smi_msg    *smi_msg,
  			   struct ipmi_recv_msg   *recv_msg,
  			   unsigned char          source_address,
  			   unsigned char          source_lun,
  			   int                    retries,
  			   unsigned int           retry_time_ms)
  {
  	struct ipmi_ipmb_addr *ipmb_addr;
  	unsigned char ipmb_seq;
  	long seqid;
  	int broadcast = 0;
  	struct ipmi_channel *chans;
  	int rv = 0;
  
  	if (addr->channel >= IPMI_MAX_CHANNELS) {
  		ipmi_inc_stat(intf, sent_invalid_commands);
  		return -EINVAL;
  	}
  
  	chans = READ_ONCE(intf->channel_list)->c;
  
  	if (chans[addr->channel].medium != IPMI_CHANNEL_MEDIUM_IPMB) {
  		ipmi_inc_stat(intf, sent_invalid_commands);
  		return -EINVAL;
  	}
  
  	if (addr->addr_type == IPMI_IPMB_BROADCAST_ADDR_TYPE) {
  		/*
  		 * Broadcasts add a zero at the beginning of the
  		 * message, but otherwise is the same as an IPMB
  		 * address.
  		 */
  		addr->addr_type = IPMI_IPMB_ADDR_TYPE;
  		broadcast = 1;
  		retries = 0; /* Don't retry broadcasts. */
  	}
  
  	/*
  	 * 9 for the header and 1 for the checksum, plus
  	 * possibly one for the broadcast.
  	 */
  	if ((msg->data_len + 10 + broadcast) > IPMI_MAX_MSG_LENGTH) {
  		ipmi_inc_stat(intf, sent_invalid_commands);
  		return -EMSGSIZE;
  	}
  
  	ipmb_addr = (struct ipmi_ipmb_addr *) addr;
  	if (ipmb_addr->lun > 3) {
  		ipmi_inc_stat(intf, sent_invalid_commands);
  		return -EINVAL;
  	}
  
  	memcpy(&recv_msg->addr, ipmb_addr, sizeof(*ipmb_addr));
  
  	if (recv_msg->msg.netfn & 0x1) {
  		/*
  		 * It's a response, so use the user's sequence
  		 * from msgid.
  		 */
  		ipmi_inc_stat(intf, sent_ipmb_responses);
  		format_ipmb_msg(smi_msg, msg, ipmb_addr, msgid,
  				msgid, broadcast,
  				source_address, source_lun);
  
  		/*
  		 * Save the receive message so we can use it
  		 * to deliver the response.
  		 */
  		smi_msg->user_data = recv_msg;
  	} else {
  		/* It's a command, so get a sequence for it. */
  		unsigned long flags;
  
  		spin_lock_irqsave(&intf->seq_lock, flags);
  
  		if (is_maintenance_mode_cmd(msg))
  			intf->ipmb_maintenance_mode_timeout =
  				maintenance_mode_timeout_ms;
  
  		if (intf->ipmb_maintenance_mode_timeout && retry_time_ms == 0)
  			/* Different default in maintenance mode */
  			retry_time_ms = default_maintenance_retry_ms;
  
  		/*
  		 * Create a sequence number with a 1 second
  		 * timeout and 4 retries.
  		 */
  		rv = intf_next_seq(intf,
  				   recv_msg,
  				   retry_time_ms,
  				   retries,
  				   broadcast,
  				   &ipmb_seq,
  				   &seqid);
  		if (rv)
  			/*
  			 * We have used up all the sequence numbers,
  			 * probably, so abort.
  			 */
  			goto out_err;
  
  		ipmi_inc_stat(intf, sent_ipmb_commands);
  
  		/*
  		 * Store the sequence number in the message,
  		 * so that when the send message response
  		 * comes back we can start the timer.
  		 */
  		format_ipmb_msg(smi_msg, msg, ipmb_addr,
  				STORE_SEQ_IN_MSGID(ipmb_seq, seqid),
  				ipmb_seq, broadcast,
  				source_address, source_lun);
  
  		/*
  		 * Copy the message into the recv message data, so we
  		 * can retransmit it later if necessary.
  		 */
  		memcpy(recv_msg->msg_data, smi_msg->data,
  		       smi_msg->data_size);
  		recv_msg->msg.data = recv_msg->msg_data;
  		recv_msg->msg.data_len = smi_msg->data_size;
  
  		/*
  		 * We don't unlock until here, because we need
  		 * to copy the completed message into the
  		 * recv_msg before we release the lock.
  		 * Otherwise, race conditions may bite us.  I
  		 * know that's pretty paranoid, but I prefer
  		 * to be correct.
  		 */
  out_err:
  		spin_unlock_irqrestore(&intf->seq_lock, flags);
  	}
  
  	return rv;
  }
  
  static int i_ipmi_req_lan(struct ipmi_smi        *intf,
  			  struct ipmi_addr       *addr,
  			  long                   msgid,
  			  struct kernel_ipmi_msg *msg,
  			  struct ipmi_smi_msg    *smi_msg,
  			  struct ipmi_recv_msg   *recv_msg,
  			  unsigned char          source_lun,
  			  int                    retries,
  			  unsigned int           retry_time_ms)
  {
  	struct ipmi_lan_addr  *lan_addr;
  	unsigned char ipmb_seq;
  	long seqid;
  	struct ipmi_channel *chans;
  	int rv = 0;
  
  	if (addr->channel >= IPMI_MAX_CHANNELS) {
  		ipmi_inc_stat(intf, sent_invalid_commands);
  		return -EINVAL;
  	}
  
  	chans = READ_ONCE(intf->channel_list)->c;
  
  	if ((chans[addr->channel].medium
  				!= IPMI_CHANNEL_MEDIUM_8023LAN)
  			&& (chans[addr->channel].medium
  			    != IPMI_CHANNEL_MEDIUM_ASYNC)) {
  		ipmi_inc_stat(intf, sent_invalid_commands);
  		return -EINVAL;
  	}
  
  	/* 11 for the header and 1 for the checksum. */
  	if ((msg->data_len + 12) > IPMI_MAX_MSG_LENGTH) {
  		ipmi_inc_stat(intf, sent_invalid_commands);
  		return -EMSGSIZE;
  	}
  
  	lan_addr = (struct ipmi_lan_addr *) addr;
  	if (lan_addr->lun > 3) {
  		ipmi_inc_stat(intf, sent_invalid_commands);
  		return -EINVAL;
  	}
  
  	memcpy(&recv_msg->addr, lan_addr, sizeof(*lan_addr));
  
  	if (recv_msg->msg.netfn & 0x1) {
  		/*
  		 * It's a response, so use the user's sequence
  		 * from msgid.
  		 */
  		ipmi_inc_stat(intf, sent_lan_responses);
  		format_lan_msg(smi_msg, msg, lan_addr, msgid,
  			       msgid, source_lun);
  
  		/*
  		 * Save the receive message so we can use it
  		 * to deliver the response.
  		 */
  		smi_msg->user_data = recv_msg;
  	} else {
  		/* It's a command, so get a sequence for it. */
  		unsigned long flags;
  
  		spin_lock_irqsave(&intf->seq_lock, flags);
  
  		/*
  		 * Create a sequence number with a 1 second
  		 * timeout and 4 retries.
  		 */
  		rv = intf_next_seq(intf,
  				   recv_msg,
  				   retry_time_ms,
  				   retries,
  				   0,
  				   &ipmb_seq,
  				   &seqid);
  		if (rv)
  			/*
  			 * We have used up all the sequence numbers,
  			 * probably, so abort.
  			 */
  			goto out_err;
  
  		ipmi_inc_stat(intf, sent_lan_commands);
  
  		/*
  		 * Store the sequence number in the message,
  		 * so that when the send message response
  		 * comes back we can start the timer.
  		 */
  		format_lan_msg(smi_msg, msg, lan_addr,
  			       STORE_SEQ_IN_MSGID(ipmb_seq, seqid),
  			       ipmb_seq, source_lun);
  
  		/*
  		 * Copy the message into the recv message data, so we
  		 * can retransmit it later if necessary.
  		 */
  		memcpy(recv_msg->msg_data, smi_msg->data,
  		       smi_msg->data_size);
  		recv_msg->msg.data = recv_msg->msg_data;
  		recv_msg->msg.data_len = smi_msg->data_size;
  
  		/*
  		 * We don't unlock until here, because we need
  		 * to copy the completed message into the
  		 * recv_msg before we release the lock.
  		 * Otherwise, race conditions may bite us.  I
  		 * know that's pretty paranoid, but I prefer
  		 * to be correct.
  		 */
  out_err:
  		spin_unlock_irqrestore(&intf->seq_lock, flags);
  	}
  
  	return rv;
  }
  
  /*
   * Separate from ipmi_request so that the user does not have to be
   * supplied in certain circumstances (mainly at panic time).  If
   * messages are supplied, they will be freed, even if an error
   * occurs.
   */
  static int i_ipmi_request(struct ipmi_user     *user,
  			  struct ipmi_smi      *intf,
  			  struct ipmi_addr     *addr,
  			  long                 msgid,
  			  struct kernel_ipmi_msg *msg,
  			  void                 *user_msg_data,
  			  void                 *supplied_smi,
  			  struct ipmi_recv_msg *supplied_recv,
  			  int                  priority,
  			  unsigned char        source_address,
  			  unsigned char        source_lun,
  			  int                  retries,
  			  unsigned int         retry_time_ms)
  {
  	struct ipmi_smi_msg *smi_msg;
  	struct ipmi_recv_msg *recv_msg;
  	int rv = 0;
  
  	if (supplied_recv)
  		recv_msg = supplied_recv;
  	else {
  		recv_msg = ipmi_alloc_recv_msg();
  		if (recv_msg == NULL) {
  			rv = -ENOMEM;
  			goto out;
  		}
  	}
  	recv_msg->user_msg_data = user_msg_data;
  
  	if (supplied_smi)
  		smi_msg = (struct ipmi_smi_msg *) supplied_smi;
  	else {
  		smi_msg = ipmi_alloc_smi_msg();
  		if (smi_msg == NULL) {
  			ipmi_free_recv_msg(recv_msg);
  			rv = -ENOMEM;
  			goto out;
  		}
  	}
  
  	rcu_read_lock();
  	if (intf->in_shutdown) {
  		rv = -ENODEV;
  		goto out_err;
  	}
  
  	recv_msg->user = user;
  	if (user)
  		/* The put happens when the message is freed. */
  		kref_get(&user->refcount);
  	recv_msg->msgid = msgid;
  	/*
  	 * Store the message to send in the receive message so timeout
  	 * responses can get the proper response data.
  	 */
  	recv_msg->msg = *msg;
  
  	if (addr->addr_type == IPMI_SYSTEM_INTERFACE_ADDR_TYPE) {
  		rv = i_ipmi_req_sysintf(intf, addr, msgid, msg, smi_msg,
  					recv_msg, retries, retry_time_ms);
  	} else if (is_ipmb_addr(addr) || is_ipmb_bcast_addr(addr)) {
  		rv = i_ipmi_req_ipmb(intf, addr, msgid, msg, smi_msg, recv_msg,
  				     source_address, source_lun,
  				     retries, retry_time_ms);
  	} else if (is_lan_addr(addr)) {
  		rv = i_ipmi_req_lan(intf, addr, msgid, msg, smi_msg, recv_msg,
  				    source_lun, retries, retry_time_ms);
  	} else {
  	    /* Unknown address type. */
  		ipmi_inc_stat(intf, sent_invalid_commands);
  		rv = -EINVAL;
  	}
  
  	if (rv) {
  out_err:
  		ipmi_free_smi_msg(smi_msg);
  		ipmi_free_recv_msg(recv_msg);
  	} else {
  		ipmi_debug_msg("Send", smi_msg->data, smi_msg->data_size);
  
  		smi_send(intf, intf->handlers, smi_msg, priority);
  	}
  	rcu_read_unlock();
  
  out:
  	return rv;
  }
  
  static int check_addr(struct ipmi_smi  *intf,
  		      struct ipmi_addr *addr,
  		      unsigned char    *saddr,
  		      unsigned char    *lun)
  {
  	if (addr->channel >= IPMI_MAX_CHANNELS)
  		return -EINVAL;
  	addr->channel = array_index_nospec(addr->channel, IPMI_MAX_CHANNELS);
  	*lun = intf->addrinfo[addr->channel].lun;
  	*saddr = intf->addrinfo[addr->channel].address;
  	return 0;
  }
  
  int ipmi_request_settime(struct ipmi_user *user,
  			 struct ipmi_addr *addr,
  			 long             msgid,
  			 struct kernel_ipmi_msg  *msg,
  			 void             *user_msg_data,
  			 int              priority,
  			 int              retries,
  			 unsigned int     retry_time_ms)
  {
  	unsigned char saddr = 0, lun = 0;
  	int rv, index;
  
  	if (!user)
  		return -EINVAL;
  
  	user = acquire_ipmi_user(user, &index);
  	if (!user)
  		return -ENODEV;
  
  	rv = check_addr(user->intf, addr, &saddr, &lun);
  	if (!rv)
  		rv = i_ipmi_request(user,
  				    user->intf,
  				    addr,
  				    msgid,
  				    msg,
  				    user_msg_data,
  				    NULL, NULL,
  				    priority,
  				    saddr,
  				    lun,
  				    retries,
  				    retry_time_ms);
  
  	release_ipmi_user(user, index);
  	return rv;
  }
  EXPORT_SYMBOL(ipmi_request_settime);
  
  int ipmi_request_supply_msgs(struct ipmi_user     *user,
  			     struct ipmi_addr     *addr,
  			     long                 msgid,
  			     struct kernel_ipmi_msg *msg,
  			     void                 *user_msg_data,
  			     void                 *supplied_smi,
  			     struct ipmi_recv_msg *supplied_recv,
  			     int                  priority)
  {
  	unsigned char saddr = 0, lun = 0;
  	int rv, index;
  
  	if (!user)
  		return -EINVAL;
  
  	user = acquire_ipmi_user(user, &index);
  	if (!user)
  		return -ENODEV;
  
  	rv = check_addr(user->intf, addr, &saddr, &lun);
  	if (!rv)
  		rv = i_ipmi_request(user,
  				    user->intf,
  				    addr,
  				    msgid,
  				    msg,
  				    user_msg_data,
  				    supplied_smi,
  				    supplied_recv,
  				    priority,
  				    saddr,
  				    lun,
  				    -1, 0);
  
  	release_ipmi_user(user, index);
  	return rv;
  }
  EXPORT_SYMBOL(ipmi_request_supply_msgs);
  
  static void bmc_device_id_handler(struct ipmi_smi *intf,
  				  struct ipmi_recv_msg *msg)
  {
  	int rv;
  
  	if ((msg->addr.addr_type != IPMI_SYSTEM_INTERFACE_ADDR_TYPE)
  			|| (msg->msg.netfn != IPMI_NETFN_APP_RESPONSE)
  			|| (msg->msg.cmd != IPMI_GET_DEVICE_ID_CMD)) {
  		dev_warn(intf->si_dev,
  			 "invalid device_id msg: addr_type=%d netfn=%x cmd=%x\n",
  			 msg->addr.addr_type, msg->msg.netfn, msg->msg.cmd);
  		return;
  	}
  
  	rv = ipmi_demangle_device_id(msg->msg.netfn, msg->msg.cmd,
  			msg->msg.data, msg->msg.data_len, &intf->bmc->fetch_id);
  	if (rv) {
  		dev_warn(intf->si_dev, "device id demangle failed: %d\n", rv);
  		intf->bmc->dyn_id_set = 0;
  	} else {
  		/*
  		 * Make sure the id data is available before setting
  		 * dyn_id_set.
  		 */
  		smp_wmb();
  		intf->bmc->dyn_id_set = 1;
  	}
  
  	wake_up(&intf->waitq);
  }
  
  static int
  send_get_device_id_cmd(struct ipmi_smi *intf)
  {
  	struct ipmi_system_interface_addr si;
  	struct kernel_ipmi_msg msg;
  
  	si.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
  	si.channel = IPMI_BMC_CHANNEL;
  	si.lun = 0;
  
  	msg.netfn = IPMI_NETFN_APP_REQUEST;
  	msg.cmd = IPMI_GET_DEVICE_ID_CMD;
  	msg.data = NULL;
  	msg.data_len = 0;
  
  	return i_ipmi_request(NULL,
  			      intf,
  			      (struct ipmi_addr *) &si,
  			      0,
  			      &msg,
  			      intf,
  			      NULL,
  			      NULL,
  			      0,
  			      intf->addrinfo[0].address,
  			      intf->addrinfo[0].lun,
  			      -1, 0);
  }
  
  static int __get_device_id(struct ipmi_smi *intf, struct bmc_device *bmc)
  {
  	int rv;
  
  	bmc->dyn_id_set = 2;
  
  	intf->null_user_handler = bmc_device_id_handler;
  
  	rv = send_get_device_id_cmd(intf);
  	if (rv)
  		return rv;
  
  	wait_event(intf->waitq, bmc->dyn_id_set != 2);
  
  	if (!bmc->dyn_id_set)
  		rv = -EIO; /* Something went wrong in the fetch. */
  
  	/* dyn_id_set makes the id data available. */
  	smp_rmb();
  
  	intf->null_user_handler = NULL;
  
  	return rv;
  }
  
  /*
   * Fetch the device id for the bmc/interface.  You must pass in either
   * bmc or intf, this code will get the other one.  If the data has
   * been recently fetched, this will just use the cached data.  Otherwise
   * it will run a new fetch.
   *
   * Except for the first time this is called (in ipmi_register_smi()),
   * this will always return good data;
   */
  static int __bmc_get_device_id(struct ipmi_smi *intf, struct bmc_device *bmc,
  			       struct ipmi_device_id *id,
  			       bool *guid_set, guid_t *guid, int intf_num)
  {
  	int rv = 0;
  	int prev_dyn_id_set, prev_guid_set;
  	bool intf_set = intf != NULL;
  
  	if (!intf) {
  		mutex_lock(&bmc->dyn_mutex);
  retry_bmc_lock:
  		if (list_empty(&bmc->intfs)) {
  			mutex_unlock(&bmc->dyn_mutex);
  			return -ENOENT;
  		}
  		intf = list_first_entry(&bmc->intfs, struct ipmi_smi,
  					bmc_link);
  		kref_get(&intf->refcount);
  		mutex_unlock(&bmc->dyn_mutex);
  		mutex_lock(&intf->bmc_reg_mutex);
  		mutex_lock(&bmc->dyn_mutex);
  		if (intf != list_first_entry(&bmc->intfs, struct ipmi_smi,
  					     bmc_link)) {
  			mutex_unlock(&intf->bmc_reg_mutex);
  			kref_put(&intf->refcount, intf_free);
  			goto retry_bmc_lock;
  		}
  	} else {
  		mutex_lock(&intf->bmc_reg_mutex);
  		bmc = intf->bmc;
  		mutex_lock(&bmc->dyn_mutex);
  		kref_get(&intf->refcount);
  	}
  
  	/* If we have a valid and current ID, just return that. */
  	if (intf->in_bmc_register ||
  	    (bmc->dyn_id_set && time_is_after_jiffies(bmc->dyn_id_expiry)))
  		goto out_noprocessing;
  
  	prev_guid_set = bmc->dyn_guid_set;
  	__get_guid(intf);
  
  	prev_dyn_id_set = bmc->dyn_id_set;
  	rv = __get_device_id(intf, bmc);
  	if (rv)
  		goto out;
  
  	/*
  	 * The guid, device id, manufacturer id, and product id should
  	 * not change on a BMC.  If it does we have to do some dancing.
  	 */
  	if (!intf->bmc_registered
  	    || (!prev_guid_set && bmc->dyn_guid_set)
  	    || (!prev_dyn_id_set && bmc->dyn_id_set)
  	    || (prev_guid_set && bmc->dyn_guid_set
  		&& !guid_equal(&bmc->guid, &bmc->fetch_guid))
  	    || bmc->id.device_id != bmc->fetch_id.device_id
  	    || bmc->id.manufacturer_id != bmc->fetch_id.manufacturer_id
  	    || bmc->id.product_id != bmc->fetch_id.product_id) {
  		struct ipmi_device_id id = bmc->fetch_id;
  		int guid_set = bmc->dyn_guid_set;
  		guid_t guid;
  
  		guid = bmc->fetch_guid;
  		mutex_unlock(&bmc->dyn_mutex);
  
  		__ipmi_bmc_unregister(intf);
  		/* Fill in the temporary BMC for good measure. */
  		intf->bmc->id = id;
  		intf->bmc->dyn_guid_set = guid_set;
  		intf->bmc->guid = guid;
  		if (__ipmi_bmc_register(intf, &id, guid_set, &guid, intf_num))
  			need_waiter(intf); /* Retry later on an error. */
  		else
  			__scan_channels(intf, &id);
  
  
  		if (!intf_set) {
  			/*
  			 * We weren't given the interface on the
  			 * command line, so restart the operation on
  			 * the next interface for the BMC.
  			 */
  			mutex_unlock(&intf->bmc_reg_mutex);
  			mutex_lock(&bmc->dyn_mutex);
  			goto retry_bmc_lock;
  		}
  
  		/* We have a new BMC, set it up. */
  		bmc = intf->bmc;
  		mutex_lock(&bmc->dyn_mutex);
  		goto out_noprocessing;
  	} else if (memcmp(&bmc->fetch_id, &bmc->id, sizeof(bmc->id)))
  		/* Version info changes, scan the channels again. */
  		__scan_channels(intf, &bmc->fetch_id);
  
  	bmc->dyn_id_expiry = jiffies + IPMI_DYN_DEV_ID_EXPIRY;
  
  out:
  	if (rv && prev_dyn_id_set) {
  		rv = 0; /* Ignore failures if we have previous data. */
  		bmc->dyn_id_set = prev_dyn_id_set;
  	}
  	if (!rv) {
  		bmc->id = bmc->fetch_id;
  		if (bmc->dyn_guid_set)
  			bmc->guid = bmc->fetch_guid;
  		else if (prev_guid_set)
  			/*
  			 * The guid used to be valid and it failed to fetch,
  			 * just use the cached value.
  			 */
  			bmc->dyn_guid_set = prev_guid_set;
  	}
  out_noprocessing:
  	if (!rv) {
  		if (id)
  			*id = bmc->id;
  
  		if (guid_set)
  			*guid_set = bmc->dyn_guid_set;
  
  		if (guid && bmc->dyn_guid_set)
  			*guid =  bmc->guid;
  	}
  
  	mutex_unlock(&bmc->dyn_mutex);
  	mutex_unlock(&intf->bmc_reg_mutex);
  
  	kref_put(&intf->refcount, intf_free);
  	return rv;
  }
  
  static int bmc_get_device_id(struct ipmi_smi *intf, struct bmc_device *bmc,
  			     struct ipmi_device_id *id,
  			     bool *guid_set, guid_t *guid)
  {
  	return __bmc_get_device_id(intf, bmc, id, guid_set, guid, -1);
  }
  
  static ssize_t device_id_show(struct device *dev,
  			      struct device_attribute *attr,
  			      char *buf)
  {
  	struct bmc_device *bmc = to_bmc_device(dev);
  	struct ipmi_device_id id;
  	int rv;
  
  	rv = bmc_get_device_id(NULL, bmc, &id, NULL, NULL);
  	if (rv)
  		return rv;
  
  	return snprintf(buf, 10, "%u\n", id.device_id);
  }
  static DEVICE_ATTR_RO(device_id);
  
  static ssize_t provides_device_sdrs_show(struct device *dev,
  					 struct device_attribute *attr,
  					 char *buf)
  {
  	struct bmc_device *bmc = to_bmc_device(dev);
  	struct ipmi_device_id id;
  	int rv;
  
  	rv = bmc_get_device_id(NULL, bmc, &id, NULL, NULL);
  	if (rv)
  		return rv;
  
  	return snprintf(buf, 10, "%u\n", (id.device_revision & 0x80) >> 7);
  }
  static DEVICE_ATTR_RO(provides_device_sdrs);
  
  static ssize_t revision_show(struct device *dev, struct device_attribute *attr,
  			     char *buf)
  {
  	struct bmc_device *bmc = to_bmc_device(dev);
  	struct ipmi_device_id id;
  	int rv;
  
  	rv = bmc_get_device_id(NULL, bmc, &id, NULL, NULL);
  	if (rv)
  		return rv;
  
  	return snprintf(buf, 20, "%u\n", id.device_revision & 0x0F);
  }
  static DEVICE_ATTR_RO(revision);
  
  static ssize_t firmware_revision_show(struct device *dev,
  				      struct device_attribute *attr,
  				      char *buf)
  {
  	struct bmc_device *bmc = to_bmc_device(dev);
  	struct ipmi_device_id id;
  	int rv;
  
  	rv = bmc_get_device_id(NULL, bmc, &id, NULL, NULL);
  	if (rv)
  		return rv;
  
  	return snprintf(buf, 20, "%u.%x\n", id.firmware_revision_1,
  			id.firmware_revision_2);
  }
  static DEVICE_ATTR_RO(firmware_revision);
  
  static ssize_t ipmi_version_show(struct device *dev,
  				 struct device_attribute *attr,
  				 char *buf)
  {
  	struct bmc_device *bmc = to_bmc_device(dev);
  	struct ipmi_device_id id;
  	int rv;
  
  	rv = bmc_get_device_id(NULL, bmc, &id, NULL, NULL);
  	if (rv)
  		return rv;
  
  	return snprintf(buf, 20, "%u.%u\n",
  			ipmi_version_major(&id),
  			ipmi_version_minor(&id));
  }
  static DEVICE_ATTR_RO(ipmi_version);
  
  static ssize_t add_dev_support_show(struct device *dev,
  				    struct device_attribute *attr,
  				    char *buf)
  {
  	struct bmc_device *bmc = to_bmc_device(dev);
  	struct ipmi_device_id id;
  	int rv;
  
  	rv = bmc_get_device_id(NULL, bmc, &id, NULL, NULL);
  	if (rv)
  		return rv;
  
  	return snprintf(buf, 10, "0x%02x\n", id.additional_device_support);
  }
  static DEVICE_ATTR(additional_device_support, S_IRUGO, add_dev_support_show,
  		   NULL);
  
  static ssize_t manufacturer_id_show(struct device *dev,
  				    struct device_attribute *attr,
  				    char *buf)
  {
  	struct bmc_device *bmc = to_bmc_device(dev);
  	struct ipmi_device_id id;
  	int rv;
  
  	rv = bmc_get_device_id(NULL, bmc, &id, NULL, NULL);
  	if (rv)
  		return rv;
  
  	return snprintf(buf, 20, "0x%6.6x\n", id.manufacturer_id);
  }
  static DEVICE_ATTR_RO(manufacturer_id);
  
  static ssize_t product_id_show(struct device *dev,
  			       struct device_attribute *attr,
  			       char *buf)
  {
  	struct bmc_device *bmc = to_bmc_device(dev);
  	struct ipmi_device_id id;
  	int rv;
  
  	rv = bmc_get_device_id(NULL, bmc, &id, NULL, NULL);
  	if (rv)
  		return rv;
  
  	return snprintf(buf, 10, "0x%4.4x\n", id.product_id);
  }
  static DEVICE_ATTR_RO(product_id);
  
  static ssize_t aux_firmware_rev_show(struct device *dev,
  				     struct device_attribute *attr,
  				     char *buf)
  {
  	struct bmc_device *bmc = to_bmc_device(dev);
  	struct ipmi_device_id id;
  	int rv;
  
  	rv = bmc_get_device_id(NULL, bmc, &id, NULL, NULL);
  	if (rv)
  		return rv;
  
  	return snprintf(buf, 21, "0x%02x 0x%02x 0x%02x 0x%02x\n",
  			id.aux_firmware_revision[3],
  			id.aux_firmware_revision[2],
  			id.aux_firmware_revision[1],
  			id.aux_firmware_revision[0]);
  }
  static DEVICE_ATTR(aux_firmware_revision, S_IRUGO, aux_firmware_rev_show, NULL);
  
  static ssize_t guid_show(struct device *dev, struct device_attribute *attr,
  			 char *buf)
  {
  	struct bmc_device *bmc = to_bmc_device(dev);
  	bool guid_set;
  	guid_t guid;
  	int rv;
  
  	rv = bmc_get_device_id(NULL, bmc, NULL, &guid_set, &guid);
  	if (rv)
  		return rv;
  	if (!guid_set)
  		return -ENOENT;
  
  	return snprintf(buf, UUID_STRING_LEN + 1 + 1, "%pUl\n", &guid);
  }
  static DEVICE_ATTR_RO(guid);
  
  static struct attribute *bmc_dev_attrs[] = {
  	&dev_attr_device_id.attr,
  	&dev_attr_provides_device_sdrs.attr,
  	&dev_attr_revision.attr,
  	&dev_attr_firmware_revision.attr,
  	&dev_attr_ipmi_version.attr,
  	&dev_attr_additional_device_support.attr,
  	&dev_attr_manufacturer_id.attr,
  	&dev_attr_product_id.attr,
  	&dev_attr_aux_firmware_revision.attr,
  	&dev_attr_guid.attr,
  	NULL
  };
  
  static umode_t bmc_dev_attr_is_visible(struct kobject *kobj,
  				       struct attribute *attr, int idx)
  {
  	struct device *dev = kobj_to_dev(kobj);
  	struct bmc_device *bmc = to_bmc_device(dev);
  	umode_t mode = attr->mode;
  	int rv;
  
  	if (attr == &dev_attr_aux_firmware_revision.attr) {
  		struct ipmi_device_id id;
  
  		rv = bmc_get_device_id(NULL, bmc, &id, NULL, NULL);
  		return (!rv && id.aux_firmware_revision_set) ? mode : 0;
  	}
  	if (attr == &dev_attr_guid.attr) {
  		bool guid_set;
  
  		rv = bmc_get_device_id(NULL, bmc, NULL, &guid_set, NULL);
  		return (!rv && guid_set) ? mode : 0;
  	}
  	return mode;
  }
  
  static const struct attribute_group bmc_dev_attr_group = {
  	.attrs		= bmc_dev_attrs,
  	.is_visible	= bmc_dev_attr_is_visible,
  };
  
  static const struct attribute_group *bmc_dev_attr_groups[] = {
  	&bmc_dev_attr_group,
  	NULL
  };
  
  static const struct device_type bmc_device_type = {
  	.groups		= bmc_dev_attr_groups,
  };
  
  static int __find_bmc_guid(struct device *dev, const void *data)
  {
  	const guid_t *guid = data;
  	struct bmc_device *bmc;
  	int rv;
  
  	if (dev->type != &bmc_device_type)
  		return 0;
  
  	bmc = to_bmc_device(dev);
  	rv = bmc->dyn_guid_set && guid_equal(&bmc->guid, guid);
  	if (rv)
  		rv = kref_get_unless_zero(&bmc->usecount);
  	return rv;
  }
  
  /*
   * Returns with the bmc's usecount incremented, if it is non-NULL.
   */
  static struct bmc_device *ipmi_find_bmc_guid(struct device_driver *drv,
  					     guid_t *guid)
  {
  	struct device *dev;
  	struct bmc_device *bmc = NULL;
  
  	dev = driver_find_device(drv, NULL, guid, __find_bmc_guid);
  	if (dev) {
  		bmc = to_bmc_device(dev);
  		put_device(dev);
  	}
  	return bmc;
  }
  
  struct prod_dev_id {
  	unsigned int  product_id;
  	unsigned char device_id;
  };
  
  static int __find_bmc_prod_dev_id(struct device *dev, const void *data)
  {
  	const struct prod_dev_id *cid = data;
  	struct bmc_device *bmc;
  	int rv;
  
  	if (dev->type != &bmc_device_type)
  		return 0;
  
  	bmc = to_bmc_device(dev);
  	rv = (bmc->id.product_id == cid->product_id
  	      && bmc->id.device_id == cid->device_id);
  	if (rv)
  		rv = kref_get_unless_zero(&bmc->usecount);
  	return rv;
  }
  
  /*
   * Returns with the bmc's usecount incremented, if it is non-NULL.
   */
  static struct bmc_device *ipmi_find_bmc_prod_dev_id(
  	struct device_driver *drv,
  	unsigned int product_id, unsigned char device_id)
  {
  	struct prod_dev_id id = {
  		.product_id = product_id,
  		.device_id = device_id,
  	};
  	struct device *dev;
  	struct bmc_device *bmc = NULL;
  
  	dev = driver_find_device(drv, NULL, &id, __find_bmc_prod_dev_id);
  	if (dev) {
  		bmc = to_bmc_device(dev);
  		put_device(dev);
  	}
  	return bmc;
  }
  
  static DEFINE_IDA(ipmi_bmc_ida);
  
  static void
  release_bmc_device(struct device *dev)
  {
  	kfree(to_bmc_device(dev));
  }
  
  static void cleanup_bmc_work(struct work_struct *work)
  {
  	struct bmc_device *bmc = container_of(work, struct bmc_device,
  					      remove_work);
  	int id = bmc->pdev.id; /* Unregister overwrites id */
  
  	platform_device_unregister(&bmc->pdev);
  	ida_simple_remove(&ipmi_bmc_ida, id);
  }
  
  static void
  cleanup_bmc_device(struct kref *ref)
  {
  	struct bmc_device *bmc = container_of(ref, struct bmc_device, usecount);
  
  	/*
  	 * Remove the platform device in a work queue to avoid issues
  	 * with removing the device attributes while reading a device
  	 * attribute.
  	 */
  	schedule_work(&bmc->remove_work);
  }
  
  /*
   * Must be called with intf->bmc_reg_mutex held.
   */
  static void __ipmi_bmc_unregister(struct ipmi_smi *intf)
  {
  	struct bmc_device *bmc = intf->bmc;
  
  	if (!intf->bmc_registered)
  		return;
  
  	sysfs_remove_link(&intf->si_dev->kobj, "bmc");
  	sysfs_remove_link(&bmc->pdev.dev.kobj, intf->my_dev_name);
  	kfree(intf->my_dev_name);
  	intf->my_dev_name = NULL;
  
  	mutex_lock(&bmc->dyn_mutex);
  	list_del(&intf->bmc_link);
  	mutex_unlock(&bmc->dyn_mutex);
  	intf->bmc = &intf->tmp_bmc;
  	kref_put(&bmc->usecount, cleanup_bmc_device);
  	intf->bmc_registered = false;
  }
  
  static void ipmi_bmc_unregister(struct ipmi_smi *intf)
  {
  	mutex_lock(&intf->bmc_reg_mutex);
  	__ipmi_bmc_unregister(intf);
  	mutex_unlock(&intf->bmc_reg_mutex);
  }
  
  /*
   * Must be called with intf->bmc_reg_mutex held.
   */
  static int __ipmi_bmc_register(struct ipmi_smi *intf,
  			       struct ipmi_device_id *id,
  			       bool guid_set, guid_t *guid, int intf_num)
  {
  	int               rv;
  	struct bmc_device *bmc;
  	struct bmc_device *old_bmc;
  
  	/*
  	 * platform_device_register() can cause bmc_reg_mutex to
  	 * be claimed because of the is_visible functions of
  	 * the attributes.  Eliminate possible recursion and
  	 * release the lock.
  	 */
  	intf->in_bmc_register = true;
  	mutex_unlock(&intf->bmc_reg_mutex);
  
  	/*
  	 * Try to find if there is an bmc_device struct
  	 * representing the interfaced BMC already
  	 */
  	mutex_lock(&ipmidriver_mutex);
  	if (guid_set)
  		old_bmc = ipmi_find_bmc_guid(&ipmidriver.driver, guid);
  	else
  		old_bmc = ipmi_find_bmc_prod_dev_id(&ipmidriver.driver,
  						    id->product_id,
  						    id->device_id);
  
  	/*
  	 * If there is already an bmc_device, free the new one,
  	 * otherwise register the new BMC device
  	 */
  	if (old_bmc) {
  		bmc = old_bmc;
  		/*
  		 * Note: old_bmc already has usecount incremented by
  		 * the BMC find functions.
  		 */
  		intf->bmc = old_bmc;
  		mutex_lock(&bmc->dyn_mutex);
  		list_add_tail(&intf->bmc_link, &bmc->intfs);
  		mutex_unlock(&bmc->dyn_mutex);
  
  		dev_info(intf->si_dev,
  			 "interfacing existing BMC (man_id: 0x%6.6x, prod_id: 0x%4.4x, dev_id: 0x%2.2x)\n",
  			 bmc->id.manufacturer_id,
  			 bmc->id.product_id,
  			 bmc->id.device_id);
  	} else {
  		bmc = kzalloc(sizeof(*bmc), GFP_KERNEL);
  		if (!bmc) {
  			rv = -ENOMEM;
  			goto out;
  		}
  		INIT_LIST_HEAD(&bmc->intfs);
  		mutex_init(&bmc->dyn_mutex);
  		INIT_WORK(&bmc->remove_work, cleanup_bmc_work);
  
  		bmc->id = *id;
  		bmc->dyn_id_set = 1;
  		bmc->dyn_guid_set = guid_set;
  		bmc->guid = *guid;
  		bmc->dyn_id_expiry = jiffies + IPMI_DYN_DEV_ID_EXPIRY;
  
  		bmc->pdev.name = "ipmi_bmc";
  
  		rv = ida_simple_get(&ipmi_bmc_ida, 0, 0, GFP_KERNEL);
  		if (rv < 0)
  			goto out;
  		bmc->pdev.dev.driver = &ipmidriver.driver;
  		bmc->pdev.id = rv;
  		bmc->pdev.dev.release = release_bmc_device;
  		bmc->pdev.dev.type = &bmc_device_type;
  		kref_init(&bmc->usecount);
  
  		intf->bmc = bmc;
  		mutex_lock(&bmc->dyn_mutex);
  		list_add_tail(&intf->bmc_link, &bmc->intfs);
  		mutex_unlock(&bmc->dyn_mutex);
  
  		rv = platform_device_register(&bmc->pdev);
  		if (rv) {
  			dev_err(intf->si_dev,
  				"Unable to register bmc device: %d\n",
  				rv);
  			goto out_list_del;
  		}
  
  		dev_info(intf->si_dev,
  			 "Found new BMC (man_id: 0x%6.6x, prod_id: 0x%4.4x, dev_id: 0x%2.2x)\n",
  			 bmc->id.manufacturer_id,
  			 bmc->id.product_id,
  			 bmc->id.device_id);
  	}
  
  	/*
  	 * create symlink from system interface device to bmc device
  	 * and back.
  	 */
  	rv = sysfs_create_link(&intf->si_dev->kobj, &bmc->pdev.dev.kobj, "bmc");
  	if (rv) {
  		dev_err(intf->si_dev, "Unable to create bmc symlink: %d\n", rv);
  		goto out_put_bmc;
  	}
  
  	if (intf_num == -1)
  		intf_num = intf->intf_num;
  	intf->my_dev_name = kasprintf(GFP_KERNEL, "ipmi%d", intf_num);
  	if (!intf->my_dev_name) {
  		rv = -ENOMEM;
  		dev_err(intf->si_dev, "Unable to allocate link from BMC: %d\n",
  			rv);
  		goto out_unlink1;
  	}
  
  	rv = sysfs_create_link(&bmc->pdev.dev.kobj, &intf->si_dev->kobj,
  			       intf->my_dev_name);
  	if (rv) {
  		kfree(intf->my_dev_name);
  		intf->my_dev_name = NULL;
  		dev_err(intf->si_dev, "Unable to create symlink to bmc: %d\n",
  			rv);
  		goto out_free_my_dev_name;
  	}
  
  	intf->bmc_registered = true;
  
  out:
  	mutex_unlock(&ipmidriver_mutex);
  	mutex_lock(&intf->bmc_reg_mutex);
  	intf->in_bmc_register = false;
  	return rv;
  
  
  out_free_my_dev_name:
  	kfree(intf->my_dev_name);
  	intf->my_dev_name = NULL;
  
  out_unlink1:
  	sysfs_remove_link(&intf->si_dev->kobj, "bmc");
  
  out_put_bmc:
  	mutex_lock(&bmc->dyn_mutex);
  	list_del(&intf->bmc_link);
  	mutex_unlock(&bmc->dyn_mutex);
  	intf->bmc = &intf->tmp_bmc;
  	kref_put(&bmc->usecount, cleanup_bmc_device);
  	goto out;
  
  out_list_del:
  	mutex_lock(&bmc->dyn_mutex);
  	list_del(&intf->bmc_link);
  	mutex_unlock(&bmc->dyn_mutex);
  	intf->bmc = &intf->tmp_bmc;
  	put_device(&bmc->pdev.dev);
  	goto out;
  }
  
  static int
  send_guid_cmd(struct ipmi_smi *intf, int chan)
  {
  	struct kernel_ipmi_msg            msg;
  	struct ipmi_system_interface_addr si;
  
  	si.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
  	si.channel = IPMI_BMC_CHANNEL;
  	si.lun = 0;
  
  	msg.netfn = IPMI_NETFN_APP_REQUEST;
  	msg.cmd = IPMI_GET_DEVICE_GUID_CMD;
  	msg.data = NULL;
  	msg.data_len = 0;
  	return i_ipmi_request(NULL,
  			      intf,
  			      (struct ipmi_addr *) &si,
  			      0,
  			      &msg,
  			      intf,
  			      NULL,
  			      NULL,
  			      0,
  			      intf->addrinfo[0].address,
  			      intf->addrinfo[0].lun,
  			      -1, 0);
  }
  
  static void guid_handler(struct ipmi_smi *intf, struct ipmi_recv_msg *msg)
  {
  	struct bmc_device *bmc = intf->bmc;
  
  	if ((msg->addr.addr_type != IPMI_SYSTEM_INTERFACE_ADDR_TYPE)
  	    || (msg->msg.netfn != IPMI_NETFN_APP_RESPONSE)
  	    || (msg->msg.cmd != IPMI_GET_DEVICE_GUID_CMD))
  		/* Not for me */
  		return;
  
  	if (msg->msg.data[0] != 0) {
  		/* Error from getting the GUID, the BMC doesn't have one. */
  		bmc->dyn_guid_set = 0;
  		goto out;
  	}
  
  	if (msg->msg.data_len < UUID_SIZE + 1) {
  		bmc->dyn_guid_set = 0;
  		dev_warn(intf->si_dev,
  			 "The GUID response from the BMC was too short, it was %d but should have been %d.  Assuming GUID is not available.\n",
  			 msg->msg.data_len, UUID_SIZE + 1);
  		goto out;
  	}
  
  	guid_copy(&bmc->fetch_guid, (guid_t *)(msg->msg.data + 1));
  	/*
  	 * Make sure the guid data is available before setting
  	 * dyn_guid_set.
  	 */
  	smp_wmb();
  	bmc->dyn_guid_set = 1;
   out:
  	wake_up(&intf->waitq);
  }
  
  static void __get_guid(struct ipmi_smi *intf)
  {
  	int rv;
  	struct bmc_device *bmc = intf->bmc;
  
  	bmc->dyn_guid_set = 2;
  	intf->null_user_handler = guid_handler;
  	rv = send_guid_cmd(intf, 0);
  	if (rv)
  		/* Send failed, no GUID available. */
  		bmc->dyn_guid_set = 0;
  
  	wait_event(intf->waitq, bmc->dyn_guid_set != 2);
  
  	/* dyn_guid_set makes the guid data available. */
  	smp_rmb();
  
  	intf->null_user_handler = NULL;
  }
  
  static int
  send_channel_info_cmd(struct ipmi_smi *intf, int chan)
  {
  	struct kernel_ipmi_msg            msg;
  	unsigned char                     data[1];
  	struct ipmi_system_interface_addr si;
  
  	si.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
  	si.channel = IPMI_BMC_CHANNEL;
  	si.lun = 0;
  
  	msg.netfn = IPMI_NETFN_APP_REQUEST;
  	msg.cmd = IPMI_GET_CHANNEL_INFO_CMD;
  	msg.data = data;
  	msg.data_len = 1;
  	data[0] = chan;
  	return i_ipmi_request(NULL,
  			      intf,
  			      (struct ipmi_addr *) &si,
  			      0,
  			      &msg,
  			      intf,
  			      NULL,
  			      NULL,
  			      0,
  			      intf->addrinfo[0].address,
  			      intf->addrinfo[0].lun,
  			      -1, 0);
  }
  
  static void
  channel_handler(struct ipmi_smi *intf, struct ipmi_recv_msg *msg)
  {
  	int rv = 0;
  	int ch;
  	unsigned int set = intf->curr_working_cset;
  	struct ipmi_channel *chans;
  
  	if ((msg->addr.addr_type == IPMI_SYSTEM_INTERFACE_ADDR_TYPE)
  	    && (msg->msg.netfn == IPMI_NETFN_APP_RESPONSE)
  	    && (msg->msg.cmd == IPMI_GET_CHANNEL_INFO_CMD)) {
  		/* It's the one we want */
  		if (msg->msg.data[0] != 0) {
  			/* Got an error from the channel, just go on. */
  
  			if (msg->msg.data[0] == IPMI_INVALID_COMMAND_ERR) {
  				/*
  				 * If the MC does not support this
  				 * command, that is legal.  We just
  				 * assume it has one IPMB at channel
  				 * zero.
  				 */
  				intf->wchannels[set].c[0].medium
  					= IPMI_CHANNEL_MEDIUM_IPMB;
  				intf->wchannels[set].c[0].protocol
  					= IPMI_CHANNEL_PROTOCOL_IPMB;
  
  				intf->channel_list = intf->wchannels + set;
  				intf->channels_ready = true;
  				wake_up(&intf->waitq);
  				goto out;
  			}
  			goto next_channel;
  		}
  		if (msg->msg.data_len < 4) {
  			/* Message not big enough, just go on. */
  			goto next_channel;
  		}
  		ch = intf->curr_channel;
  		chans = intf->wchannels[set].c;
  		chans[ch].medium = msg->msg.data[2] & 0x7f;
  		chans[ch].protocol = msg->msg.data[3] & 0x1f;
  
   next_channel:
  		intf->curr_channel++;
  		if (intf->curr_channel >= IPMI_MAX_CHANNELS) {
  			intf->channel_list = intf->wchannels + set;
  			intf->channels_ready = true;
  			wake_up(&intf->waitq);
  		} else {
  			intf->channel_list = intf->wchannels + set;
  			intf->channels_ready = true;
  			rv = send_channel_info_cmd(intf, intf->curr_channel);
  		}
  
  		if (rv) {
  			/* Got an error somehow, just give up. */
  			dev_warn(intf->si_dev,
  				 "Error sending channel information for channel %d: %d\n",
  				 intf->curr_channel, rv);
  
  			intf->channel_list = intf->wchannels + set;
  			intf->channels_ready = true;
  			wake_up(&intf->waitq);
  		}
  	}
   out:
  	return;
  }
  
  /*
   * Must be holding intf->bmc_reg_mutex to call this.
   */
  static int __scan_channels(struct ipmi_smi *intf, struct ipmi_device_id *id)
  {
  	int rv;
  
  	if (ipmi_version_major(id) > 1
  			|| (ipmi_version_major(id) == 1
  			    && ipmi_version_minor(id) >= 5)) {
  		unsigned int set;
  
  		/*
  		 * Start scanning the channels to see what is
  		 * available.
  		 */
  		set = !intf->curr_working_cset;
  		intf->curr_working_cset = set;
  		memset(&intf->wchannels[set], 0,
  		       sizeof(struct ipmi_channel_set));
  
  		intf->null_user_handler = channel_handler;
  		intf->curr_channel = 0;
  		rv = send_channel_info_cmd(intf, 0);
  		if (rv) {
  			dev_warn(intf->si_dev,
  				 "Error sending channel information for channel 0, %d\n",
  				 rv);
  			return -EIO;
  		}
  
  		/* Wait for the channel info to be read. */
  		wait_event(intf->waitq, intf->channels_ready);
  		intf->null_user_handler = NULL;
  	} else {
  		unsigned int set = intf->curr_working_cset;
  
  		/* Assume a single IPMB channel at zero. */
  		intf->wchannels[set].c[0].medium = IPMI_CHANNEL_MEDIUM_IPMB;
  		intf->wchannels[set].c[0].protocol = IPMI_CHANNEL_PROTOCOL_IPMB;
  		intf->channel_list = intf->wchannels + set;
  		intf->channels_ready = true;
  	}
  
  	return 0;
  }
  
  static void ipmi_poll(struct ipmi_smi *intf)
  {
  	if (intf->handlers->poll)
  		intf->handlers->poll(intf->send_info);
  	/* In case something came in */
  	handle_new_recv_msgs(intf);
  }
  
  void ipmi_poll_interface(struct ipmi_user *user)
  {
  	ipmi_poll(user->intf);
  }
  EXPORT_SYMBOL(ipmi_poll_interface);
  
  static void redo_bmc_reg(struct work_struct *work)
  {
  	struct ipmi_smi *intf = container_of(work, struct ipmi_smi,
  					     bmc_reg_work);
  
  	if (!intf->in_shutdown)
  		bmc_get_device_id(intf, NULL, NULL, NULL, NULL);
  
  	kref_put(&intf->refcount, intf_free);
  }
  
  int ipmi_register_smi(const struct ipmi_smi_handlers *handlers,
  		      void		       *send_info,
  		      struct device            *si_dev,
  		      unsigned char            slave_addr)
  {
  	int              i, j;
  	int              rv;
  	struct ipmi_smi *intf, *tintf;
  	struct list_head *link;
  	struct ipmi_device_id id;
  
  	/*
  	 * Make sure the driver is actually initialized, this handles
  	 * problems with initialization order.
  	 */
  	rv = ipmi_init_msghandler();
  	if (rv)
  		return rv;
  
  	intf = kzalloc(sizeof(*intf), GFP_KERNEL);
  	if (!intf)
  		return -ENOMEM;
  
  	rv = init_srcu_struct(&intf->users_srcu);
  	if (rv) {
  		kfree(intf);
  		return rv;
  	}
  
  
  	intf->bmc = &intf->tmp_bmc;
  	INIT_LIST_HEAD(&intf->bmc->intfs);
  	mutex_init(&intf->bmc->dyn_mutex);
  	INIT_LIST_HEAD(&intf->bmc_link);
  	mutex_init(&intf->bmc_reg_mutex);
  	intf->intf_num = -1; /* Mark it invalid for now. */
  	kref_init(&intf->refcount);
  	INIT_WORK(&intf->bmc_reg_work, redo_bmc_reg);
  	intf->si_dev = si_dev;
  	for (j = 0; j < IPMI_MAX_CHANNELS; j++) {
  		intf->addrinfo[j].address = IPMI_BMC_SLAVE_ADDR;
  		intf->addrinfo[j].lun = 2;
  	}
  	if (slave_addr != 0)
  		intf->addrinfo[0].address = slave_addr;
  	INIT_LIST_HEAD(&intf->users);
  	intf->handlers = handlers;
  	intf->send_info = send_info;
  	spin_lock_init(&intf->seq_lock);
  	for (j = 0; j < IPMI_IPMB_NUM_SEQ; j++) {
  		intf->seq_table[j].inuse = 0;
  		intf->seq_table[j].seqid = 0;
  	}
  	intf->curr_seq = 0;
  	spin_lock_init(&intf->waiting_rcv_msgs_lock);
  	INIT_LIST_HEAD(&intf->waiting_rcv_msgs);
  	tasklet_init(&intf->recv_tasklet,
  		     smi_recv_tasklet,
  		     (unsigned long) intf);
  	atomic_set(&intf->watchdog_pretimeouts_to_deliver, 0);
  	spin_lock_init(&intf->xmit_msgs_lock);
  	INIT_LIST_HEAD(&intf->xmit_msgs);
  	INIT_LIST_HEAD(&intf->hp_xmit_msgs);
  	spin_lock_init(&intf->events_lock);
  	spin_lock_init(&intf->watch_lock);
  	atomic_set(&intf->event_waiters, 0);
  	intf->ticks_to_req_ev = IPMI_REQUEST_EV_TIME;
  	INIT_LIST_HEAD(&intf->waiting_events);
  	intf->waiting_events_count = 0;
  	mutex_init(&intf->cmd_rcvrs_mutex);
  	spin_lock_init(&intf->maintenance_mode_lock);
  	INIT_LIST_HEAD(&intf->cmd_rcvrs);
  	init_waitqueue_head(&intf->waitq);
  	for (i = 0; i < IPMI_NUM_STATS; i++)
  		atomic_set(&intf->stats[i], 0);
  
  	mutex_lock(&ipmi_interfaces_mutex);
  	/* Look for a hole in the numbers. */
  	i = 0;
  	link = &ipmi_interfaces;
  	list_for_each_entry_rcu(tintf, &ipmi_interfaces, link) {
  		if (tintf->intf_num != i) {
  			link = &tintf->link;
  			break;
  		}
  		i++;
  	}
  	/* Add the new interface in numeric order. */
  	if (i == 0)
  		list_add_rcu(&intf->link, &ipmi_interfaces);
  	else
  		list_add_tail_rcu(&intf->link, link);
  
  	rv = handlers->start_processing(send_info, intf);
  	if (rv)
  		goto out_err;
  
  	rv = __bmc_get_device_id(intf, NULL, &id, NULL, NULL, i);
  	if (rv) {
  		dev_err(si_dev, "Unable to get the device id: %d\n", rv);
  		goto out_err_started;
  	}
  
  	mutex_lock(&intf->bmc_reg_mutex);
  	rv = __scan_channels(intf, &id);
  	mutex_unlock(&intf->bmc_reg_mutex);
  	if (rv)
  		goto out_err_bmc_reg;
  
  	/*
  	 * Keep memory order straight for RCU readers.  Make
  	 * sure everything else is committed to memory before
  	 * setting intf_num to mark the interface valid.
  	 */
  	smp_wmb();
  	intf->intf_num = i;
  	mutex_unlock(&ipmi_interfaces_mutex);
  
  	/* After this point the interface is legal to use. */
  	call_smi_watchers(i, intf->si_dev);
  
  	return 0;
  
   out_err_bmc_reg:
  	ipmi_bmc_unregister(intf);
   out_err_started:
  	if (intf->handlers->shutdown)
  		intf->handlers->shutdown(intf->send_info);
   out_err:
  	list_del_rcu(&intf->link);
  	mutex_unlock(&ipmi_interfaces_mutex);
  	synchronize_srcu(&ipmi_interfaces_srcu);
  	cleanup_srcu_struct(&intf->users_srcu);
  	kref_put(&intf->refcount, intf_free);
  
  	return rv;
  }
  EXPORT_SYMBOL(ipmi_register_smi);
  
  static void deliver_smi_err_response(struct ipmi_smi *intf,
  				     struct ipmi_smi_msg *msg,
  				     unsigned char err)
  {
  	msg->rsp[0] = msg->data[0] | 4;
  	msg->rsp[1] = msg->data[1];
  	msg->rsp[2] = err;
  	msg->rsp_size = 3;
  	/* It's an error, so it will never requeue, no need to check return. */
  	handle_one_recv_msg(intf, msg);
  }
  
  static void cleanup_smi_msgs(struct ipmi_smi *intf)
  {
  	int              i;
  	struct seq_table *ent;
  	struct ipmi_smi_msg *msg;
  	struct list_head *entry;
  	struct list_head tmplist;
  
  	/* Clear out our transmit queues and hold the messages. */
  	INIT_LIST_HEAD(&tmplist);
  	list_splice_tail(&intf->hp_xmit_msgs, &tmplist);
  	list_splice_tail(&intf->xmit_msgs, &tmplist);
  
  	/* Current message first, to preserve order */
  	while (intf->curr_msg && !list_empty(&intf->waiting_rcv_msgs)) {
  		/* Wait for the message to clear out. */
  		schedule_timeout(1);
  	}
  
  	/* No need for locks, the interface is down. */
  
  	/*
  	 * Return errors for all pending messages in queue and in the
  	 * tables waiting for remote responses.
  	 */
  	while (!list_empty(&tmplist)) {
  		entry = tmplist.next;
  		list_del(entry);
  		msg = list_entry(entry, struct ipmi_smi_msg, link);
  		deliver_smi_err_response(intf, msg, IPMI_ERR_UNSPECIFIED);
  	}
  
  	for (i = 0; i < IPMI_IPMB_NUM_SEQ; i++) {
  		ent = &intf->seq_table[i];
  		if (!ent->inuse)
  			continue;
  		deliver_err_response(intf, ent->recv_msg, IPMI_ERR_UNSPECIFIED);
  	}
  }
  
  void ipmi_unregister_smi(struct ipmi_smi *intf)
  {
  	struct ipmi_smi_watcher *w;
  	int intf_num = intf->intf_num, index;
  
  	mutex_lock(&ipmi_interfaces_mutex);
  	intf->intf_num = -1;
  	intf->in_shutdown = true;
  	list_del_rcu(&intf->link);
  	mutex_unlock(&ipmi_interfaces_mutex);
  	synchronize_srcu(&ipmi_interfaces_srcu);
  
  	/* At this point no users can be added to the interface. */
  
  	/*
  	 * Call all the watcher interfaces to tell them that
  	 * an interface is going away.
  	 */
  	mutex_lock(&smi_watchers_mutex);
  	list_for_each_entry(w, &smi_watchers, link)
  		w->smi_gone(intf_num);
  	mutex_unlock(&smi_watchers_mutex);
  
  	index = srcu_read_lock(&intf->users_srcu);
  	while (!list_empty(&intf->users)) {
  		struct ipmi_user *user =
  			container_of(list_next_rcu(&intf->users),
  				     struct ipmi_user, link);
  
  		_ipmi_destroy_user(user);
  	}
  	srcu_read_unlock(&intf->users_srcu, index);
  
  	if (intf->handlers->shutdown)
  		intf->handlers->shutdown(intf->send_info);
  
  	cleanup_smi_msgs(intf);
  
  	ipmi_bmc_unregister(intf);
  
  	cleanup_srcu_struct(&intf->users_srcu);
  	kref_put(&intf->refcount, intf_free);
  }
  EXPORT_SYMBOL(ipmi_unregister_smi);
  
  static int handle_ipmb_get_msg_rsp(struct ipmi_smi *intf,
  				   struct ipmi_smi_msg *msg)
  {
  	struct ipmi_ipmb_addr ipmb_addr;
  	struct ipmi_recv_msg  *recv_msg;
  
  	/*
  	 * This is 11, not 10, because the response must contain a
  	 * completion code.
  	 */
  	if (msg->rsp_size < 11) {
  		/* Message not big enough, just ignore it. */
  		ipmi_inc_stat(intf, invalid_ipmb_responses);
  		return 0;
  	}
  
  	if (msg->rsp[2] != 0) {
  		/* An error getting the response, just ignore it. */
  		return 0;
  	}
  
  	ipmb_addr.addr_type = IPMI_IPMB_ADDR_TYPE;
  	ipmb_addr.slave_addr = msg->rsp[6];
  	ipmb_addr.channel = msg->rsp[3] & 0x0f;
  	ipmb_addr.lun = msg->rsp[7] & 3;
  
  	/*
  	 * It's a response from a remote entity.  Look up the sequence
  	 * number and handle the response.
  	 */
  	if (intf_find_seq(intf,
  			  msg->rsp[7] >> 2,
  			  msg->rsp[3] & 0x0f,
  			  msg->rsp[8],
  			  (msg->rsp[4] >> 2) & (~1),
  			  (struct ipmi_addr *) &ipmb_addr,
  			  &recv_msg)) {
  		/*
  		 * We were unable to find the sequence number,
  		 * so just nuke the message.
  		 */
  		ipmi_inc_stat(intf, unhandled_ipmb_responses);
  		return 0;
  	}
  
  	memcpy(recv_msg->msg_data, &msg->rsp[9], msg->rsp_size - 9);
  	/*
  	 * The other fields matched, so no need to set them, except
  	 * for netfn, which needs to be the response that was
  	 * returned, not the request value.
  	 */
  	recv_msg->msg.netfn = msg->rsp[4] >> 2;
  	recv_msg->msg.data = recv_msg->msg_data;
  	recv_msg->msg.data_len = msg->rsp_size - 10;
  	recv_msg->recv_type = IPMI_RESPONSE_RECV_TYPE;
  	if (deliver_response(intf, recv_msg))
  		ipmi_inc_stat(intf, unhandled_ipmb_responses);
  	else
  		ipmi_inc_stat(intf, handled_ipmb_responses);
  
  	return 0;
  }
  
  static int handle_ipmb_get_msg_cmd(struct ipmi_smi *intf,
  				   struct ipmi_smi_msg *msg)
  {
  	struct cmd_rcvr          *rcvr;
  	int                      rv = 0;
  	unsigned char            netfn;
  	unsigned char            cmd;
  	unsigned char            chan;
  	struct ipmi_user         *user = NULL;
  	struct ipmi_ipmb_addr    *ipmb_addr;
  	struct ipmi_recv_msg     *recv_msg;
  
  	if (msg->rsp_size < 10) {
  		/* Message not big enough, just ignore it. */
  		ipmi_inc_stat(intf, invalid_commands);
  		return 0;
  	}
  
  	if (msg->rsp[2] != 0) {
  		/* An error getting the response, just ignore it. */
  		return 0;
  	}
  
  	netfn = msg->rsp[4] >> 2;
  	cmd = msg->rsp[8];
  	chan = msg->rsp[3] & 0xf;
  
  	rcu_read_lock();
  	rcvr = find_cmd_rcvr(intf, netfn, cmd, chan);
  	if (rcvr) {
  		user = rcvr->user;
  		kref_get(&user->refcount);
  	} else
  		user = NULL;
  	rcu_read_unlock();
  
  	if (user == NULL) {
  		/* We didn't find a user, deliver an error response. */
  		ipmi_inc_stat(intf, unhandled_commands);
  
  		msg->data[0] = (IPMI_NETFN_APP_REQUEST << 2);
  		msg->data[1] = IPMI_SEND_MSG_CMD;
  		msg->data[2] = msg->rsp[3];
  		msg->data[3] = msg->rsp[6];
  		msg->data[4] = ((netfn + 1) << 2) | (msg->rsp[7] & 0x3);
  		msg->data[5] = ipmb_checksum(&msg->data[3], 2);
  		msg->data[6] = intf->addrinfo[msg->rsp[3] & 0xf].address;
  		/* rqseq/lun */
  		msg->data[7] = (msg->rsp[7] & 0xfc) | (msg->rsp[4] & 0x3);
  		msg->data[8] = msg->rsp[8]; /* cmd */
  		msg->data[9] = IPMI_INVALID_CMD_COMPLETION_CODE;
  		msg->data[10] = ipmb_checksum(&msg->data[6], 4);
  		msg->data_size = 11;
  
  		ipmi_debug_msg("Invalid command:", msg->data, msg->data_size);
  
  		rcu_read_lock();
  		if (!intf->in_shutdown) {
  			smi_send(intf, intf->handlers, msg, 0);
  			/*
  			 * We used the message, so return the value
  			 * that causes it to not be freed or
  			 * queued.
  			 */
  			rv = -1;
  		}
  		rcu_read_unlock();
  	} else {
  		recv_msg = ipmi_alloc_recv_msg();
  		if (!recv_msg) {
  			/*
  			 * We couldn't allocate memory for the
  			 * message, so requeue it for handling
  			 * later.
  			 */
  			rv = 1;
  			kref_put(&user->refcount, free_user);
  		} else {
  			/* Extract the source address from the data. */
  			ipmb_addr = (struct ipmi_ipmb_addr *) &recv_msg->addr;
  			ipmb_addr->addr_type = IPMI_IPMB_ADDR_TYPE;
  			ipmb_addr->slave_addr = msg->rsp[6];
  			ipmb_addr->lun = msg->rsp[7] & 3;
  			ipmb_addr->channel = msg->rsp[3] & 0xf;
  
  			/*
  			 * Extract the rest of the message information
  			 * from the IPMB header.
  			 */
  			recv_msg->user = user;
  			recv_msg->recv_type = IPMI_CMD_RECV_TYPE;
  			recv_msg->msgid = msg->rsp[7] >> 2;
  			recv_msg->msg.netfn = msg->rsp[4] >> 2;
  			recv_msg->msg.cmd = msg->rsp[8];
  			recv_msg->msg.data = recv_msg->msg_data;
  
  			/*
  			 * We chop off 10, not 9 bytes because the checksum
  			 * at the end also needs to be removed.
  			 */
  			recv_msg->msg.data_len = msg->rsp_size - 10;
  			memcpy(recv_msg->msg_data, &msg->rsp[9],
  			       msg->rsp_size - 10);
  			if (deliver_response(intf, recv_msg))
  				ipmi_inc_stat(intf, unhandled_commands);
  			else
  				ipmi_inc_stat(intf, handled_commands);
  		}
  	}
  
  	return rv;
  }
  
  static int handle_lan_get_msg_rsp(struct ipmi_smi *intf,
  				  struct ipmi_smi_msg *msg)
  {
  	struct ipmi_lan_addr  lan_addr;
  	struct ipmi_recv_msg  *recv_msg;
  
  
  	/*
  	 * This is 13, not 12, because the response must contain a
  	 * completion code.
  	 */
  	if (msg->rsp_size < 13) {
  		/* Message not big enough, just ignore it. */
  		ipmi_inc_stat(intf, invalid_lan_responses);
  		return 0;
  	}
  
  	if (msg->rsp[2] != 0) {
  		/* An error getting the response, just ignore it. */
  		return 0;
  	}
  
  	lan_addr.addr_type = IPMI_LAN_ADDR_TYPE;
  	lan_addr.session_handle = msg->rsp[4];
  	lan_addr.remote_SWID = msg->rsp[8];
  	lan_addr.local_SWID = msg->rsp[5];
  	lan_addr.channel = msg->rsp[3] & 0x0f;
  	lan_addr.privilege = msg->rsp[3] >> 4;
  	lan_addr.lun = msg->rsp[9] & 3;
  
  	/*
  	 * It's a response from a remote entity.  Look up the sequence
  	 * number and handle the response.
  	 */
  	if (intf_find_seq(intf,
  			  msg->rsp[9] >> 2,
  			  msg->rsp[3] & 0x0f,
  			  msg->rsp[10],
  			  (msg->rsp[6] >> 2) & (~1),
  			  (struct ipmi_addr *) &lan_addr,
  			  &recv_msg)) {
  		/*
  		 * We were unable to find the sequence number,
  		 * so just nuke the message.
  		 */
  		ipmi_inc_stat(intf, unhandled_lan_responses);
  		return 0;
  	}
  
  	memcpy(recv_msg->msg_data, &msg->rsp[11], msg->rsp_size - 11);
  	/*
  	 * The other fields matched, so no need to set them, except
  	 * for netfn, which needs to be the response that was
  	 * returned, not the request value.
  	 */
  	recv_msg->msg.netfn = msg->rsp[6] >> 2;
  	recv_msg->msg.data = recv_msg->msg_data;
  	recv_msg->msg.data_len = msg->rsp_size - 12;
  	recv_msg->recv_type = IPMI_RESPONSE_RECV_TYPE;
  	if (deliver_response(intf, recv_msg))
  		ipmi_inc_stat(intf, unhandled_lan_responses);
  	else
  		ipmi_inc_stat(intf, handled_lan_responses);
  
  	return 0;
  }
  
  static int handle_lan_get_msg_cmd(struct ipmi_smi *intf,
  				  struct ipmi_smi_msg *msg)
  {
  	struct cmd_rcvr          *rcvr;
  	int                      rv = 0;
  	unsigned char            netfn;
  	unsigned char            cmd;
  	unsigned char            chan;
  	struct ipmi_user         *user = NULL;
  	struct ipmi_lan_addr     *lan_addr;
  	struct ipmi_recv_msg     *recv_msg;
  
  	if (msg->rsp_size < 12) {
  		/* Message not big enough, just ignore it. */
  		ipmi_inc_stat(intf, invalid_commands);
  		return 0;
  	}
  
  	if (msg->rsp[2] != 0) {
  		/* An error getting the response, just ignore it. */
  		return 0;
  	}
  
  	netfn = msg->rsp[6] >> 2;
  	cmd = msg->rsp[10];
  	chan = msg->rsp[3] & 0xf;
  
  	rcu_read_lock();
  	rcvr = find_cmd_rcvr(intf, netfn, cmd, chan);
  	if (rcvr) {
  		user = rcvr->user;
  		kref_get(&user->refcount);
  	} else
  		user = NULL;
  	rcu_read_unlock();
  
  	if (user == NULL) {
  		/* We didn't find a user, just give up. */
  		ipmi_inc_stat(intf, unhandled_commands);
  
  		/*
  		 * Don't do anything with these messages, just allow
  		 * them to be freed.
  		 */
  		rv = 0;
  	} else {
  		recv_msg = ipmi_alloc_recv_msg();
  		if (!recv_msg) {
  			/*
  			 * We couldn't allocate memory for the
  			 * message, so requeue it for handling later.
  			 */
  			rv = 1;
  			kref_put(&user->refcount, free_user);
  		} else {
  			/* Extract the source address from the data. */
  			lan_addr = (struct ipmi_lan_addr *) &recv_msg->addr;
  			lan_addr->addr_type = IPMI_LAN_ADDR_TYPE;
  			lan_addr->session_handle = msg->rsp[4];
  			lan_addr->remote_SWID = msg->rsp[8];
  			lan_addr->local_SWID = msg->rsp[5];
  			lan_addr->lun = msg->rsp[9] & 3;
  			lan_addr->channel = msg->rsp[3] & 0xf;
  			lan_addr->privilege = msg->rsp[3] >> 4;
  
  			/*
  			 * Extract the rest of the message information
  			 * from the IPMB header.
  			 */
  			recv_msg->user = user;
  			recv_msg->recv_type = IPMI_CMD_RECV_TYPE;
  			recv_msg->msgid = msg->rsp[9] >> 2;
  			recv_msg->msg.netfn = msg->rsp[6] >> 2;
  			recv_msg->msg.cmd = msg->rsp[10];
  			recv_msg->msg.data = recv_msg->msg_data;
  
  			/*
  			 * We chop off 12, not 11 bytes because the checksum
  			 * at the end also needs to be removed.
  			 */
  			recv_msg->msg.data_len = msg->rsp_size - 12;
  			memcpy(recv_msg->msg_data, &msg->rsp[11],
  			       msg->rsp_size - 12);
  			if (deliver_response(intf, recv_msg))
  				ipmi_inc_stat(intf, unhandled_commands);
  			else
  				ipmi_inc_stat(intf, handled_commands);
  		}
  	}
  
  	return rv;
  }
  
  /*
   * This routine will handle "Get Message" command responses with
   * channels that use an OEM Medium. The message format belongs to
   * the OEM.  See IPMI 2.0 specification, Chapter 6 and
   * Chapter 22, sections 22.6 and 22.24 for more details.
   */
  static int handle_oem_get_msg_cmd(struct ipmi_smi *intf,
  				  struct ipmi_smi_msg *msg)
  {
  	struct cmd_rcvr       *rcvr;
  	int                   rv = 0;
  	unsigned char         netfn;
  	unsigned char         cmd;
  	unsigned char         chan;
  	struct ipmi_user *user = NULL;
  	struct ipmi_system_interface_addr *smi_addr;
  	struct ipmi_recv_msg  *recv_msg;
  
  	/*
  	 * We expect the OEM SW to perform error checking
  	 * so we just do some basic sanity checks
  	 */
  	if (msg->rsp_size < 4) {
  		/* Message not big enough, just ignore it. */
  		ipmi_inc_stat(intf, invalid_commands);
  		return 0;
  	}
  
  	if (msg->rsp[2] != 0) {
  		/* An error getting the response, just ignore it. */
  		return 0;
  	}
  
  	/*
  	 * This is an OEM Message so the OEM needs to know how
  	 * handle the message. We do no interpretation.
  	 */
  	netfn = msg->rsp[0] >> 2;
  	cmd = msg->rsp[1];
  	chan = msg->rsp[3] & 0xf;
  
  	rcu_read_lock();
  	rcvr = find_cmd_rcvr(intf, netfn, cmd, chan);
  	if (rcvr) {
  		user = rcvr->user;
  		kref_get(&user->refcount);
  	} else
  		user = NULL;
  	rcu_read_unlock();
  
  	if (user == NULL) {
  		/* We didn't find a user, just give up. */
  		ipmi_inc_stat(intf, unhandled_commands);
  
  		/*
  		 * Don't do anything with these messages, just allow
  		 * them to be freed.
  		 */
  
  		rv = 0;
  	} else {
  		recv_msg = ipmi_alloc_recv_msg();
  		if (!recv_msg) {
  			/*
  			 * We couldn't allocate memory for the
  			 * message, so requeue it for handling
  			 * later.
  			 */
  			rv = 1;
  			kref_put(&user->refcount, free_user);
  		} else {
  			/*
  			 * OEM Messages are expected to be delivered via
  			 * the system interface to SMS software.  We might
  			 * need to visit this again depending on OEM
  			 * requirements
  			 */
  			smi_addr = ((struct ipmi_system_interface_addr *)
  				    &recv_msg->addr);
  			smi_addr->addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
  			smi_addr->channel = IPMI_BMC_CHANNEL;
  			smi_addr->lun = msg->rsp[0] & 3;
  
  			recv_msg->user = user;
  			recv_msg->user_msg_data = NULL;
  			recv_msg->recv_type = IPMI_OEM_RECV_TYPE;
  			recv_msg->msg.netfn = msg->rsp[0] >> 2;
  			recv_msg->msg.cmd = msg->rsp[1];
  			recv_msg->msg.data = recv_msg->msg_data;
  
  			/*
  			 * The message starts at byte 4 which follows the
  			 * the Channel Byte in the "GET MESSAGE" command
  			 */
  			recv_msg->msg.data_len = msg->rsp_size - 4;
  			memcpy(recv_msg->msg_data, &msg->rsp[4],
  			       msg->rsp_size - 4);
  			if (deliver_response(intf, recv_msg))
  				ipmi_inc_stat(intf, unhandled_commands);
  			else
  				ipmi_inc_stat(intf, handled_commands);
  		}
  	}
  
  	return rv;
  }
  
  static void copy_event_into_recv_msg(struct ipmi_recv_msg *recv_msg,
  				     struct ipmi_smi_msg  *msg)
  {
  	struct ipmi_system_interface_addr *smi_addr;
  
  	recv_msg->msgid = 0;
  	smi_addr = (struct ipmi_system_interface_addr *) &recv_msg->addr;
  	smi_addr->addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
  	smi_addr->channel = IPMI_BMC_CHANNEL;
  	smi_addr->lun = msg->rsp[0] & 3;
  	recv_msg->recv_type = IPMI_ASYNC_EVENT_RECV_TYPE;
  	recv_msg->msg.netfn = msg->rsp[0] >> 2;
  	recv_msg->msg.cmd = msg->rsp[1];
  	memcpy(recv_msg->msg_data, &msg->rsp[3], msg->rsp_size - 3);
  	recv_msg->msg.data = recv_msg->msg_data;
  	recv_msg->msg.data_len = msg->rsp_size - 3;
  }
  
  static int handle_read_event_rsp(struct ipmi_smi *intf,
  				 struct ipmi_smi_msg *msg)
  {
  	struct ipmi_recv_msg *recv_msg, *recv_msg2;
  	struct list_head     msgs;
  	struct ipmi_user     *user;
  	int rv = 0, deliver_count = 0, index;
  	unsigned long        flags;
  
  	if (msg->rsp_size < 19) {
  		/* Message is too small to be an IPMB event. */
  		ipmi_inc_stat(intf, invalid_events);
  		return 0;
  	}
  
  	if (msg->rsp[2] != 0) {
  		/* An error getting the event, just ignore it. */
  		return 0;
  	}
  
  	INIT_LIST_HEAD(&msgs);
  
  	spin_lock_irqsave(&intf->events_lock, flags);
  
  	ipmi_inc_stat(intf, events);
  
  	/*
  	 * Allocate and fill in one message for every user that is
  	 * getting events.
  	 */
  	index = srcu_read_lock(&intf->users_srcu);
  	list_for_each_entry_rcu(user, &intf->users, link) {
  		if (!user->gets_events)
  			continue;
  
  		recv_msg = ipmi_alloc_recv_msg();
  		if (!recv_msg) {
  			rcu_read_unlock();
  			list_for_each_entry_safe(recv_msg, recv_msg2, &msgs,
  						 link) {
  				list_del(&recv_msg->link);
  				ipmi_free_recv_msg(recv_msg);
  			}
  			/*
  			 * We couldn't allocate memory for the
  			 * message, so requeue it for handling
  			 * later.
  			 */
  			rv = 1;
  			goto out;
  		}
  
  		deliver_count++;
  
  		copy_event_into_recv_msg(recv_msg, msg);
  		recv_msg->user = user;
  		kref_get(&user->refcount);
  		list_add_tail(&recv_msg->link, &msgs);
  	}
  	srcu_read_unlock(&intf->users_srcu, index);
  
  	if (deliver_count) {
  		/* Now deliver all the messages. */
  		list_for_each_entry_safe(recv_msg, recv_msg2, &msgs, link) {
  			list_del(&recv_msg->link);
  			deliver_local_response(intf, recv_msg);
  		}
  	} else if (intf->waiting_events_count < MAX_EVENTS_IN_QUEUE) {
  		/*
  		 * No one to receive the message, put it in queue if there's
  		 * not already too many things in the queue.
  		 */
  		recv_msg = ipmi_alloc_recv_msg();
  		if (!recv_msg) {
  			/*
  			 * We couldn't allocate memory for the
  			 * message, so requeue it for handling
  			 * later.
  			 */
  			rv = 1;
  			goto out;
  		}
  
  		copy_event_into_recv_msg(recv_msg, msg);
  		list_add_tail(&recv_msg->link, &intf->waiting_events);
  		intf->waiting_events_count++;
  	} else if (!intf->event_msg_printed) {
  		/*
  		 * There's too many things in the queue, discard this
  		 * message.
  		 */
  		dev_warn(intf->si_dev,
  			 "Event queue full, discarding incoming events\n");
  		intf->event_msg_printed = 1;
  	}
  
   out:
  	spin_unlock_irqrestore(&intf->events_lock, flags);
  
  	return rv;
  }
  
  static int handle_bmc_rsp(struct ipmi_smi *intf,
  			  struct ipmi_smi_msg *msg)
  {
  	struct ipmi_recv_msg *recv_msg;
  	struct ipmi_system_interface_addr *smi_addr;
  
  	recv_msg = (struct ipmi_recv_msg *) msg->user_data;
  	if (recv_msg == NULL) {
  		dev_warn(intf->si_dev,
  			 "IPMI message received with no owner. This could be because of a malformed message, or because of a hardware error.  Contact your hardware vendor for assistance.\n");
  		return 0;
  	}
  
  	recv_msg->recv_type = IPMI_RESPONSE_RECV_TYPE;
  	recv_msg->msgid = msg->msgid;
  	smi_addr = ((struct ipmi_system_interface_addr *)
  		    &recv_msg->addr);
  	smi_addr->addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
  	smi_addr->channel = IPMI_BMC_CHANNEL;
  	smi_addr->lun = msg->rsp[0] & 3;
  	recv_msg->msg.netfn = msg->rsp[0] >> 2;
  	recv_msg->msg.cmd = msg->rsp[1];
  	memcpy(recv_msg->msg_data, &msg->rsp[2], msg->rsp_size - 2);
  	recv_msg->msg.data = recv_msg->msg_data;
  	recv_msg->msg.data_len = msg->rsp_size - 2;
  	deliver_local_response(intf, recv_msg);
  
  	return 0;
  }
  
  /*
   * Handle a received message.  Return 1 if the message should be requeued,
   * 0 if the message should be freed, or -1 if the message should not
   * be freed or requeued.
   */
  static int handle_one_recv_msg(struct ipmi_smi *intf,
  			       struct ipmi_smi_msg *msg)
  {
  	int requeue;
  	int chan;
  
  	ipmi_debug_msg("Recv:", msg->rsp, msg->rsp_size);
  
  	if ((msg->data_size >= 2)
  	    && (msg->data[0] == (IPMI_NETFN_APP_REQUEST << 2))
  	    && (msg->data[1] == IPMI_SEND_MSG_CMD)
  	    && (msg->user_data == NULL)) {
  
  		if (intf->in_shutdown)
  			goto free_msg;
  
  		/*
  		 * This is the local response to a command send, start
  		 * the timer for these.  The user_data will not be
  		 * NULL if this is a response send, and we will let
  		 * response sends just go through.
  		 */
  
  		/*
  		 * Check for errors, if we get certain errors (ones
  		 * that mean basically we can try again later), we
  		 * ignore them and start the timer.  Otherwise we
  		 * report the error immediately.
  		 */
  		if ((msg->rsp_size >= 3) && (msg->rsp[2] != 0)
  		    && (msg->rsp[2] != IPMI_NODE_BUSY_ERR)
  		    && (msg->rsp[2] != IPMI_LOST_ARBITRATION_ERR)
  		    && (msg->rsp[2] != IPMI_BUS_ERR)
  		    && (msg->rsp[2] != IPMI_NAK_ON_WRITE_ERR)) {
  			int ch = msg->rsp[3] & 0xf;
  			struct ipmi_channel *chans;
  
  			/* Got an error sending the message, handle it. */
  
  			chans = READ_ONCE(intf->channel_list)->c;
  			if ((chans[ch].medium == IPMI_CHANNEL_MEDIUM_8023LAN)
  			    || (chans[ch].medium == IPMI_CHANNEL_MEDIUM_ASYNC))
  				ipmi_inc_stat(intf, sent_lan_command_errs);
  			else
  				ipmi_inc_stat(intf, sent_ipmb_command_errs);
  			intf_err_seq(intf, msg->msgid, msg->rsp[2]);
  		} else
  			/* The message was sent, start the timer. */
  			intf_start_seq_timer(intf, msg->msgid);
  free_msg:
  		requeue = 0;
  		goto out;
  
  	} else if (msg->rsp_size < 2) {
  		/* Message is too small to be correct. */
  		dev_warn(intf->si_dev,
  			 "BMC returned too small a message for netfn %x cmd %x, got %d bytes\n",
  			 (msg->data[0] >> 2) | 1, msg->data[1], msg->rsp_size);
  
  		/* Generate an error response for the message. */
  		msg->rsp[0] = msg->data[0] | (1 << 2);
  		msg->rsp[1] = msg->data[1];
  		msg->rsp[2] = IPMI_ERR_UNSPECIFIED;
  		msg->rsp_size = 3;
  	} else if (((msg->rsp[0] >> 2) != ((msg->data[0] >> 2) | 1))
  		   || (msg->rsp[1] != msg->data[1])) {
  		/*
  		 * The NetFN and Command in the response is not even
  		 * marginally correct.
  		 */
  		dev_warn(intf->si_dev,
  			 "BMC returned incorrect response, expected netfn %x cmd %x, got netfn %x cmd %x\n",
  			 (msg->data[0] >> 2) | 1, msg->data[1],
  			 msg->rsp[0] >> 2, msg->rsp[1]);
  
  		/* Generate an error response for the message. */
  		msg->rsp[0] = msg->data[0] | (1 << 2);
  		msg->rsp[1] = msg->data[1];
  		msg->rsp[2] = IPMI_ERR_UNSPECIFIED;
  		msg->rsp_size = 3;
  	}
  
  	if ((msg->rsp[0] == ((IPMI_NETFN_APP_REQUEST|1) << 2))
  	    && (msg->rsp[1] == IPMI_SEND_MSG_CMD)
  	    && (msg->user_data != NULL)) {
  		/*
  		 * It's a response to a response we sent.  For this we
  		 * deliver a send message response to the user.
  		 */
  		struct ipmi_recv_msg *recv_msg = msg->user_data;
  
  		requeue = 0;
  		if (msg->rsp_size < 2)
  			/* Message is too small to be correct. */
  			goto out;
  
  		chan = msg->data[2] & 0x0f;
  		if (chan >= IPMI_MAX_CHANNELS)
  			/* Invalid channel number */
  			goto out;
  
  		if (!recv_msg)
  			goto out;
  
  		recv_msg->recv_type = IPMI_RESPONSE_RESPONSE_TYPE;
  		recv_msg->msg.data = recv_msg->msg_data;
  		recv_msg->msg.data_len = 1;
  		recv_msg->msg_data[0] = msg->rsp[2];
  		deliver_local_response(intf, recv_msg);
  	} else if ((msg->rsp[0] == ((IPMI_NETFN_APP_REQUEST|1) << 2))
  		   && (msg->rsp[1] == IPMI_GET_MSG_CMD)) {
  		struct ipmi_channel   *chans;
  
  		/* It's from the receive queue. */
  		chan = msg->rsp[3] & 0xf;
  		if (chan >= IPMI_MAX_CHANNELS) {
  			/* Invalid channel number */
  			requeue = 0;
  			goto out;
  		}
  
  		/*
  		 * We need to make sure the channels have been initialized.
  		 * The channel_handler routine will set the "curr_channel"
  		 * equal to or greater than IPMI_MAX_CHANNELS when all the
  		 * channels for this interface have been initialized.
  		 */
  		if (!intf->channels_ready) {
  			requeue = 0; /* Throw the message away */
  			goto out;
  		}
  
  		chans = READ_ONCE(intf->channel_list)->c;
  
  		switch (chans[chan].medium) {
  		case IPMI_CHANNEL_MEDIUM_IPMB:
  			if (msg->rsp[4] & 0x04) {
  				/*
  				 * It's a response, so find the
  				 * requesting message and send it up.
  				 */
  				requeue = handle_ipmb_get_msg_rsp(intf, msg);
  			} else {
  				/*
  				 * It's a command to the SMS from some other
  				 * entity.  Handle that.
  				 */
  				requeue = handle_ipmb_get_msg_cmd(intf, msg);
  			}
  			break;
  
  		case IPMI_CHANNEL_MEDIUM_8023LAN:
  		case IPMI_CHANNEL_MEDIUM_ASYNC:
  			if (msg->rsp[6] & 0x04) {
  				/*
  				 * It's a response, so find the
  				 * requesting message and send it up.
  				 */
  				requeue = handle_lan_get_msg_rsp(intf, msg);
  			} else {
  				/*
  				 * It's a command to the SMS from some other
  				 * entity.  Handle that.
  				 */
  				requeue = handle_lan_get_msg_cmd(intf, msg);
  			}
  			break;
  
  		default:
  			/* Check for OEM Channels.  Clients had better
  			   register for these commands. */
  			if ((chans[chan].medium >= IPMI_CHANNEL_MEDIUM_OEM_MIN)
  			    && (chans[chan].medium
  				<= IPMI_CHANNEL_MEDIUM_OEM_MAX)) {
  				requeue = handle_oem_get_msg_cmd(intf, msg);
  			} else {
  				/*
  				 * We don't handle the channel type, so just
  				 * free the message.
  				 */
  				requeue = 0;
  			}
  		}
  
  	} else if ((msg->rsp[0] == ((IPMI_NETFN_APP_REQUEST|1) << 2))
  		   && (msg->rsp[1] == IPMI_READ_EVENT_MSG_BUFFER_CMD)) {
  		/* It's an asynchronous event. */
  		requeue = handle_read_event_rsp(intf, msg);
  	} else {
  		/* It's a response from the local BMC. */
  		requeue = handle_bmc_rsp(intf, msg);
  	}
  
   out:
  	return requeue;
  }
  
  /*
   * If there are messages in the queue or pretimeouts, handle them.
   */
  static void handle_new_recv_msgs(struct ipmi_smi *intf)
  {
  	struct ipmi_smi_msg  *smi_msg;
  	unsigned long        flags = 0;
  	int                  rv;
  	int                  run_to_completion = intf->run_to_completion;
  
  	/* See if any waiting messages need to be processed. */
  	if (!run_to_completion)
  		spin_lock_irqsave(&intf->waiting_rcv_msgs_lock, flags);
  	while (!list_empty(&intf->waiting_rcv_msgs)) {
  		smi_msg = list_entry(intf->waiting_rcv_msgs.next,
  				     struct ipmi_smi_msg, link);
  		list_del(&smi_msg->link);
  		if (!run_to_completion)
  			spin_unlock_irqrestore(&intf->waiting_rcv_msgs_lock,
  					       flags);
  		rv = handle_one_recv_msg(intf, smi_msg);
  		if (!run_to_completion)
  			spin_lock_irqsave(&intf->waiting_rcv_msgs_lock, flags);
  		if (rv > 0) {
  			/*
  			 * To preserve message order, quit if we
  			 * can't handle a message.  Add the message
  			 * back at the head, this is safe because this
  			 * tasklet is the only thing that pulls the
  			 * messages.
  			 */
  			list_add(&smi_msg->link, &intf->waiting_rcv_msgs);
  			break;
  		} else {
  			if (rv == 0)
  				/* Message handled */
  				ipmi_free_smi_msg(smi_msg);
  			/* If rv < 0, fatal error, del but don't free. */
  		}
  	}
  	if (!run_to_completion)
  		spin_unlock_irqrestore(&intf->waiting_rcv_msgs_lock, flags);
  
  	/*
  	 * If the pretimout count is non-zero, decrement one from it and
  	 * deliver pretimeouts to all the users.
  	 */
  	if (atomic_add_unless(&intf->watchdog_pretimeouts_to_deliver, -1, 0)) {
  		struct ipmi_user *user;
  		int index;
  
  		index = srcu_read_lock(&intf->users_srcu);
  		list_for_each_entry_rcu(user, &intf->users, link) {
  			if (user->handler->ipmi_watchdog_pretimeout)
  				user->handler->ipmi_watchdog_pretimeout(
  					user->handler_data);
  		}
  		srcu_read_unlock(&intf->users_srcu, index);
  	}
  }
  
  static void smi_recv_tasklet(unsigned long val)
  {
  	unsigned long flags = 0; /* keep us warning-free. */
  	struct ipmi_smi *intf = (struct ipmi_smi *) val;
  	int run_to_completion = intf->run_to_completion;
  	struct ipmi_smi_msg *newmsg = NULL;
  
  	/*
  	 * Start the next message if available.
  	 *
  	 * Do this here, not in the actual receiver, because we may deadlock
  	 * because the lower layer is allowed to hold locks while calling
  	 * message delivery.
  	 */
  
  	rcu_read_lock();
  
  	if (!run_to_completion)
  		spin_lock_irqsave(&intf->xmit_msgs_lock, flags);
  	if (intf->curr_msg == NULL && !intf->in_shutdown) {
  		struct list_head *entry = NULL;
  
  		/* Pick the high priority queue first. */
  		if (!list_empty(&intf->hp_xmit_msgs))
  			entry = intf->hp_xmit_msgs.next;
  		else if (!list_empty(&intf->xmit_msgs))
  			entry = intf->xmit_msgs.next;
  
  		if (entry) {
  			list_del(entry);
  			newmsg = list_entry(entry, struct ipmi_smi_msg, link);
  			intf->curr_msg = newmsg;
  		}
  	}
  
  	if (!run_to_completion)
  		spin_unlock_irqrestore(&intf->xmit_msgs_lock, flags);
  	if (newmsg)
  		intf->handlers->sender(intf->send_info, newmsg);
  
  	rcu_read_unlock();
  
  	handle_new_recv_msgs(intf);
  }
  
  /* Handle a new message from the lower layer. */
  void ipmi_smi_msg_received(struct ipmi_smi *intf,
  			   struct ipmi_smi_msg *msg)
  {
  	unsigned long flags = 0; /* keep us warning-free. */
  	int run_to_completion = intf->run_to_completion;
  
  	/*
  	 * To preserve message order, we keep a queue and deliver from
  	 * a tasklet.
  	 */
  	if (!run_to_completion)
  		spin_lock_irqsave(&intf->waiting_rcv_msgs_lock, flags);
  	list_add_tail(&msg->link, &intf->waiting_rcv_msgs);
  	if (!run_to_completion)
  		spin_unlock_irqrestore(&intf->waiting_rcv_msgs_lock,
  				       flags);
  
  	if (!run_to_completion)
  		spin_lock_irqsave(&intf->xmit_msgs_lock, flags);
  	/*
  	 * We can get an asynchronous event or receive message in addition
  	 * to commands we send.
  	 */
  	if (msg == intf->curr_msg)
  		intf->curr_msg = NULL;
  	if (!run_to_completion)
  		spin_unlock_irqrestore(&intf->xmit_msgs_lock, flags);
  
  	if (run_to_completion)
  		smi_recv_tasklet((unsigned long) intf);
  	else
  		tasklet_schedule(&intf->recv_tasklet);
  }
  EXPORT_SYMBOL(ipmi_smi_msg_received);
  
  void ipmi_smi_watchdog_pretimeout(struct ipmi_smi *intf)
  {
  	if (intf->in_shutdown)
  		return;
  
  	atomic_set(&intf->watchdog_pretimeouts_to_deliver, 1);
  	tasklet_schedule(&intf->recv_tasklet);
  }
  EXPORT_SYMBOL(ipmi_smi_watchdog_pretimeout);
  
  static struct ipmi_smi_msg *
  smi_from_recv_msg(struct ipmi_smi *intf, struct ipmi_recv_msg *recv_msg,
  		  unsigned char seq, long seqid)
  {
  	struct ipmi_smi_msg *smi_msg = ipmi_alloc_smi_msg();
  	if (!smi_msg)
  		/*
  		 * If we can't allocate the message, then just return, we
  		 * get 4 retries, so this should be ok.
  		 */
  		return NULL;
  
  	memcpy(smi_msg->data, recv_msg->msg.data, recv_msg->msg.data_len);
  	smi_msg->data_size = recv_msg->msg.data_len;
  	smi_msg->msgid = STORE_SEQ_IN_MSGID(seq, seqid);
  
  	ipmi_debug_msg("Resend: ", smi_msg->data, smi_msg->data_size);
  
  	return smi_msg;
  }
  
  static void check_msg_timeout(struct ipmi_smi *intf, struct seq_table *ent,
  			      struct list_head *timeouts,
  			      unsigned long timeout_period,
  			      int slot, unsigned long *flags,
  			      bool *need_timer)
  {
  	struct ipmi_recv_msg *msg;
  
  	if (intf->in_shutdown)
  		return;
  
  	if (!ent->inuse)
  		return;
  
  	if (timeout_period < ent->timeout) {
  		ent->timeout -= timeout_period;
  		*need_timer = true;
  		return;
  	}
  
  	if (ent->retries_left == 0) {
  		/* The message has used all its retries. */
  		ent->inuse = 0;
  		smi_remove_watch(intf, IPMI_WATCH_MASK_CHECK_MESSAGES);
  		msg = ent->recv_msg;
  		list_add_tail(&msg->link, timeouts);
  		if (ent->broadcast)
  			ipmi_inc_stat(intf, timed_out_ipmb_broadcasts);
  		else if (is_lan_addr(&ent->recv_msg->addr))
  			ipmi_inc_stat(intf, timed_out_lan_commands);
  		else
  			ipmi_inc_stat(intf, timed_out_ipmb_commands);
  	} else {
  		struct ipmi_smi_msg *smi_msg;
  		/* More retries, send again. */
  
  		*need_timer = true;
  
  		/*
  		 * Start with the max timer, set to normal timer after
  		 * the message is sent.
  		 */
  		ent->timeout = MAX_MSG_TIMEOUT;
  		ent->retries_left--;
  		smi_msg = smi_from_recv_msg(intf, ent->recv_msg, slot,
  					    ent->seqid);
  		if (!smi_msg) {
  			if (is_lan_addr(&ent->recv_msg->addr))
  				ipmi_inc_stat(intf,
  					      dropped_rexmit_lan_commands);
  			else
  				ipmi_inc_stat(intf,
  					      dropped_rexmit_ipmb_commands);
  			return;
  		}
  
  		spin_unlock_irqrestore(&intf->seq_lock, *flags);
  
  		/*
  		 * Send the new message.  We send with a zero
  		 * priority.  It timed out, I doubt time is that
  		 * critical now, and high priority messages are really
  		 * only for messages to the local MC, which don't get
  		 * resent.
  		 */
  		if (intf->handlers) {
  			if (is_lan_addr(&ent->recv_msg->addr))
  				ipmi_inc_stat(intf,
  					      retransmitted_lan_commands);
  			else
  				ipmi_inc_stat(intf,
  					      retransmitted_ipmb_commands);
  
  			smi_send(intf, intf->handlers, smi_msg, 0);
  		} else
  			ipmi_free_smi_msg(smi_msg);
  
  		spin_lock_irqsave(&intf->seq_lock, *flags);
  	}
  }
  
  static bool ipmi_timeout_handler(struct ipmi_smi *intf,
  				 unsigned long timeout_period)
  {
  	struct list_head     timeouts;
  	struct ipmi_recv_msg *msg, *msg2;
  	unsigned long        flags;
  	int                  i;
  	bool                 need_timer = false;
  
  	if (!intf->bmc_registered) {
  		kref_get(&intf->refcount);
  		if (!schedule_work(&intf->bmc_reg_work)) {
  			kref_put(&intf->refcount, intf_free);
  			need_timer = true;
  		}
  	}
  
  	/*
  	 * Go through the seq table and find any messages that
  	 * have timed out, putting them in the timeouts
  	 * list.
  	 */
  	INIT_LIST_HEAD(&timeouts);
  	spin_lock_irqsave(&intf->seq_lock, flags);
  	if (intf->ipmb_maintenance_mode_timeout) {
  		if (intf->ipmb_maintenance_mode_timeout <= timeout_period)
  			intf->ipmb_maintenance_mode_timeout = 0;
  		else
  			intf->ipmb_maintenance_mode_timeout -= timeout_period;
  	}
  	for (i = 0; i < IPMI_IPMB_NUM_SEQ; i++)
  		check_msg_timeout(intf, &intf->seq_table[i],
  				  &timeouts, timeout_period, i,
  				  &flags, &need_timer);
  	spin_unlock_irqrestore(&intf->seq_lock, flags);
  
  	list_for_each_entry_safe(msg, msg2, &timeouts, link)
  		deliver_err_response(intf, msg, IPMI_TIMEOUT_COMPLETION_CODE);
  
  	/*
  	 * Maintenance mode handling.  Check the timeout
  	 * optimistically before we claim the lock.  It may
  	 * mean a timeout gets missed occasionally, but that
  	 * only means the timeout gets extended by one period
  	 * in that case.  No big deal, and it avoids the lock
  	 * most of the time.
  	 */
  	if (intf->auto_maintenance_timeout > 0) {
  		spin_lock_irqsave(&intf->maintenance_mode_lock, flags);
  		if (intf->auto_maintenance_timeout > 0) {
  			intf->auto_maintenance_timeout
  				-= timeout_period;
  			if (!intf->maintenance_mode
  			    && (intf->auto_maintenance_timeout <= 0)) {
  				intf->maintenance_mode_enable = false;
  				maintenance_mode_update(intf);
  			}
  		}
  		spin_unlock_irqrestore(&intf->maintenance_mode_lock,
  				       flags);
  	}
  
  	tasklet_schedule(&intf->recv_tasklet);
  
  	return need_timer;
  }
  
  static void ipmi_request_event(struct ipmi_smi *intf)
  {
  	/* No event requests when in maintenance mode. */
  	if (intf->maintenance_mode_enable)
  		return;
  
  	if (!intf->in_shutdown)
  		intf->handlers->request_events(intf->send_info);
  }
  
  static struct timer_list ipmi_timer;
  
  static atomic_t stop_operation;
  
  static void ipmi_timeout(struct timer_list *unused)
  {
  	struct ipmi_smi *intf;
  	bool need_timer = false;
  	int index;
  
  	if (atomic_read(&stop_operation))
  		return;
  
  	index = srcu_read_lock(&ipmi_interfaces_srcu);
  	list_for_each_entry_rcu(intf, &ipmi_interfaces, link) {
  		if (atomic_read(&intf->event_waiters)) {
  			intf->ticks_to_req_ev--;
  			if (intf->ticks_to_req_ev == 0) {
  				ipmi_request_event(intf);
  				intf->ticks_to_req_ev = IPMI_REQUEST_EV_TIME;
  			}
  			need_timer = true;
  		}
  
  		need_timer |= ipmi_timeout_handler(intf, IPMI_TIMEOUT_TIME);
  	}
  	srcu_read_unlock(&ipmi_interfaces_srcu, index);
  
  	if (need_timer)
  		mod_timer(&ipmi_timer, jiffies + IPMI_TIMEOUT_JIFFIES);
  }
  
  static void need_waiter(struct ipmi_smi *intf)
  {
  	/* Racy, but worst case we start the timer twice. */
  	if (!timer_pending(&ipmi_timer))
  		mod_timer(&ipmi_timer, jiffies + IPMI_TIMEOUT_JIFFIES);
  }
  
  static atomic_t smi_msg_inuse_count = ATOMIC_INIT(0);
  static atomic_t recv_msg_inuse_count = ATOMIC_INIT(0);
  
  static void free_smi_msg(struct ipmi_smi_msg *msg)
  {
  	atomic_dec(&smi_msg_inuse_count);
  	kfree(msg);
  }
  
  struct ipmi_smi_msg *ipmi_alloc_smi_msg(void)
  {
  	struct ipmi_smi_msg *rv;
  	rv = kmalloc(sizeof(struct ipmi_smi_msg), GFP_ATOMIC);
  	if (rv) {
  		rv->done = free_smi_msg;
  		rv->user_data = NULL;
  		atomic_inc(&smi_msg_inuse_count);
  	}
  	return rv;
  }
  EXPORT_SYMBOL(ipmi_alloc_smi_msg);
  
  static void free_recv_msg(struct ipmi_recv_msg *msg)
  {
  	atomic_dec(&recv_msg_inuse_count);
  	kfree(msg);
  }
  
  static struct ipmi_recv_msg *ipmi_alloc_recv_msg(void)
  {
  	struct ipmi_recv_msg *rv;
  
  	rv = kmalloc(sizeof(struct ipmi_recv_msg), GFP_ATOMIC);
  	if (rv) {
  		rv->user = NULL;
  		rv->done = free_recv_msg;
  		atomic_inc(&recv_msg_inuse_count);
  	}
  	return rv;
  }
  
  void ipmi_free_recv_msg(struct ipmi_recv_msg *msg)
  {
  	if (msg->user)
  		kref_put(&msg->user->refcount, free_user);
  	msg->done(msg);
  }
  EXPORT_SYMBOL(ipmi_free_recv_msg);
  
  static atomic_t panic_done_count = ATOMIC_INIT(0);
  
  static void dummy_smi_done_handler(struct ipmi_smi_msg *msg)
  {
  	atomic_dec(&panic_done_count);
  }
  
  static void dummy_recv_done_handler(struct ipmi_recv_msg *msg)
  {
  	atomic_dec(&panic_done_count);
  }
  
  /*
   * Inside a panic, send a message and wait for a response.
   */
  static void ipmi_panic_request_and_wait(struct ipmi_smi *intf,
  					struct ipmi_addr *addr,
  					struct kernel_ipmi_msg *msg)
  {
  	struct ipmi_smi_msg  smi_msg;
  	struct ipmi_recv_msg recv_msg;
  	int rv;
  
  	smi_msg.done = dummy_smi_done_handler;
  	recv_msg.done = dummy_recv_done_handler;
  	atomic_add(2, &panic_done_count);
  	rv = i_ipmi_request(NULL,
  			    intf,
  			    addr,
  			    0,
  			    msg,
  			    intf,
  			    &smi_msg,
  			    &recv_msg,
  			    0,
  			    intf->addrinfo[0].address,
  			    intf->addrinfo[0].lun,
  			    0, 1); /* Don't retry, and don't wait. */
  	if (rv)
  		atomic_sub(2, &panic_done_count);
  	else if (intf->handlers->flush_messages)
  		intf->handlers->flush_messages(intf->send_info);
  
  	while (atomic_read(&panic_done_count) != 0)
  		ipmi_poll(intf);
  }
  
  static void event_receiver_fetcher(struct ipmi_smi *intf,
  				   struct ipmi_recv_msg *msg)
  {
  	if ((msg->addr.addr_type == IPMI_SYSTEM_INTERFACE_ADDR_TYPE)
  	    && (msg->msg.netfn == IPMI_NETFN_SENSOR_EVENT_RESPONSE)
  	    && (msg->msg.cmd == IPMI_GET_EVENT_RECEIVER_CMD)
  	    && (msg->msg.data[0] == IPMI_CC_NO_ERROR)) {
  		/* A get event receiver command, save it. */
  		intf->event_receiver = msg->msg.data[1];
  		intf->event_receiver_lun = msg->msg.data[2] & 0x3;
  	}
  }
  
  static void device_id_fetcher(struct ipmi_smi *intf, struct ipmi_recv_msg *msg)
  {
  	if ((msg->addr.addr_type == IPMI_SYSTEM_INTERFACE_ADDR_TYPE)
  	    && (msg->msg.netfn == IPMI_NETFN_APP_RESPONSE)
  	    && (msg->msg.cmd == IPMI_GET_DEVICE_ID_CMD)
  	    && (msg->msg.data[0] == IPMI_CC_NO_ERROR)) {
  		/*
  		 * A get device id command, save if we are an event
  		 * receiver or generator.
  		 */
  		intf->local_sel_device = (msg->msg.data[6] >> 2) & 1;
  		intf->local_event_generator = (msg->msg.data[6] >> 5) & 1;
  	}
  }
  
  static void send_panic_events(struct ipmi_smi *intf, char *str)
  {
  	struct kernel_ipmi_msg msg;
  	unsigned char data[16];
  	struct ipmi_system_interface_addr *si;
  	struct ipmi_addr addr;
  	char *p = str;
  	struct ipmi_ipmb_addr *ipmb;
  	int j;
  
  	if (ipmi_send_panic_event == IPMI_SEND_PANIC_EVENT_NONE)
  		return;
  
  	si = (struct ipmi_system_interface_addr *) &addr;
  	si->addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
  	si->channel = IPMI_BMC_CHANNEL;
  	si->lun = 0;
  
  	/* Fill in an event telling that we have failed. */
  	msg.netfn = 0x04; /* Sensor or Event. */
  	msg.cmd = 2; /* Platform event command. */
  	msg.data = data;
  	msg.data_len = 8;
  	data[0] = 0x41; /* Kernel generator ID, IPMI table 5-4 */
  	data[1] = 0x03; /* This is for IPMI 1.0. */
  	data[2] = 0x20; /* OS Critical Stop, IPMI table 36-3 */
  	data[4] = 0x6f; /* Sensor specific, IPMI table 36-1 */
  	data[5] = 0xa1; /* Runtime stop OEM bytes 2 & 3. */
  
  	/*
  	 * Put a few breadcrumbs in.  Hopefully later we can add more things
  	 * to make the panic events more useful.
  	 */
  	if (str) {
  		data[3] = str[0];
  		data[6] = str[1];
  		data[7] = str[2];
  	}
  
  	/* Send the event announcing the panic. */
  	ipmi_panic_request_and_wait(intf, &addr, &msg);
  
  	/*
  	 * On every interface, dump a bunch of OEM event holding the
  	 * string.
  	 */
  	if (ipmi_send_panic_event != IPMI_SEND_PANIC_EVENT_STRING || !str)
  		return;
  
  	/*
  	 * intf_num is used as an marker to tell if the
  	 * interface is valid.  Thus we need a read barrier to
  	 * make sure data fetched before checking intf_num
  	 * won't be used.
  	 */
  	smp_rmb();
  
  	/*
  	 * First job here is to figure out where to send the
  	 * OEM events.  There's no way in IPMI to send OEM
  	 * events using an event send command, so we have to
  	 * find the SEL to put them in and stick them in
  	 * there.
  	 */
  
  	/* Get capabilities from the get device id. */
  	intf->local_sel_device = 0;
  	intf->local_event_generator = 0;
  	intf->event_receiver = 0;
  
  	/* Request the device info from the local MC. */
  	msg.netfn = IPMI_NETFN_APP_REQUEST;
  	msg.cmd = IPMI_GET_DEVICE_ID_CMD;
  	msg.data = NULL;
  	msg.data_len = 0;
  	intf->null_user_handler = device_id_fetcher;
  	ipmi_panic_request_and_wait(intf, &addr, &msg);
  
  	if (intf->local_event_generator) {
  		/* Request the event receiver from the local MC. */
  		msg.netfn = IPMI_NETFN_SENSOR_EVENT_REQUEST;
  		msg.cmd = IPMI_GET_EVENT_RECEIVER_CMD;
  		msg.data = NULL;
  		msg.data_len = 0;
  		intf->null_user_handler = event_receiver_fetcher;
  		ipmi_panic_request_and_wait(intf, &addr, &msg);
  	}
  	intf->null_user_handler = NULL;
  
  	/*
  	 * Validate the event receiver.  The low bit must not
  	 * be 1 (it must be a valid IPMB address), it cannot
  	 * be zero, and it must not be my address.
  	 */
  	if (((intf->event_receiver & 1) == 0)
  	    && (intf->event_receiver != 0)
  	    && (intf->event_receiver != intf->addrinfo[0].address)) {
  		/*
  		 * The event receiver is valid, send an IPMB
  		 * message.
  		 */
  		ipmb = (struct ipmi_ipmb_addr *) &addr;
  		ipmb->addr_type = IPMI_IPMB_ADDR_TYPE;
  		ipmb->channel = 0; /* FIXME - is this right? */
  		ipmb->lun = intf->event_receiver_lun;
  		ipmb->slave_addr = intf->event_receiver;
  	} else if (intf->local_sel_device) {
  		/*
  		 * The event receiver was not valid (or was
  		 * me), but I am an SEL device, just dump it
  		 * in my SEL.
  		 */
  		si = (struct ipmi_system_interface_addr *) &addr;
  		si->addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
  		si->channel = IPMI_BMC_CHANNEL;
  		si->lun = 0;
  	} else
  		return; /* No where to send the event. */
  
  	msg.netfn = IPMI_NETFN_STORAGE_REQUEST; /* Storage. */
  	msg.cmd = IPMI_ADD_SEL_ENTRY_CMD;
  	msg.data = data;
  	msg.data_len = 16;
  
  	j = 0;
  	while (*p) {
  		int size = strlen(p);
  
  		if (size > 11)
  			size = 11;
  		data[0] = 0;
  		data[1] = 0;
  		data[2] = 0xf0; /* OEM event without timestamp. */
  		data[3] = intf->addrinfo[0].address;
  		data[4] = j++; /* sequence # */
  		/*
  		 * Always give 11 bytes, so strncpy will fill
  		 * it with zeroes for me.
  		 */
  		strncpy(data+5, p, 11);
  		p += size;
  
  		ipmi_panic_request_and_wait(intf, &addr, &msg);
  	}
  }
  
  static int has_panicked;
  
  static int panic_event(struct notifier_block *this,
  		       unsigned long         event,
  		       void                  *ptr)
  {
  	struct ipmi_smi *intf;
  	struct ipmi_user *user;
  
  	if (has_panicked)
  		return NOTIFY_DONE;
  	has_panicked = 1;
  
  	/* For every registered interface, set it to run to completion. */
  	list_for_each_entry_rcu(intf, &ipmi_interfaces, link) {
  		if (!intf->handlers || intf->intf_num == -1)
  			/* Interface is not ready. */
  			continue;
  
  		if (!intf->handlers->poll)
  			continue;
  
  		/*
  		 * If we were interrupted while locking xmit_msgs_lock or
  		 * waiting_rcv_msgs_lock, the corresponding list may be
  		 * corrupted.  In this case, drop items on the list for
  		 * the safety.
  		 */
  		if (!spin_trylock(&intf->xmit_msgs_lock)) {
  			INIT_LIST_HEAD(&intf->xmit_msgs);
  			INIT_LIST_HEAD(&intf->hp_xmit_msgs);
  		} else
  			spin_unlock(&intf->xmit_msgs_lock);
  
  		if (!spin_trylock(&intf->waiting_rcv_msgs_lock))
  			INIT_LIST_HEAD(&intf->waiting_rcv_msgs);
  		else
  			spin_unlock(&intf->waiting_rcv_msgs_lock);
  
  		intf->run_to_completion = 1;
  		if (intf->handlers->set_run_to_completion)
  			intf->handlers->set_run_to_completion(intf->send_info,
  							      1);
  
  		list_for_each_entry_rcu(user, &intf->users, link) {
  			if (user->handler->ipmi_panic_handler)
  				user->handler->ipmi_panic_handler(
  					user->handler_data);
  		}
  
  		send_panic_events(intf, ptr);
  	}
  
  	return NOTIFY_DONE;
  }
  
  /* Must be called with ipmi_interfaces_mutex held. */
  static int ipmi_register_driver(void)
  {
  	int rv;
  
  	if (drvregistered)
  		return 0;
  
  	rv = driver_register(&ipmidriver.driver);
  	if (rv)
  		pr_err("Could not register IPMI driver\n");
  	else
  		drvregistered = true;
  	return rv;
  }
  
  static struct notifier_block panic_block = {
  	.notifier_call	= panic_event,
  	.next		= NULL,
  	.priority	= 200	/* priority: INT_MAX >= x >= 0 */
  };
  
  static int ipmi_init_msghandler(void)
  {
  	int rv;
  
  	mutex_lock(&ipmi_interfaces_mutex);
  	rv = ipmi_register_driver();
  	if (rv)
  		goto out;
  	if (initialized)
  		goto out;
  
  	init_srcu_struct(&ipmi_interfaces_srcu);
  
  	timer_setup(&ipmi_timer, ipmi_timeout, 0);
  	mod_timer(&ipmi_timer, jiffies + IPMI_TIMEOUT_JIFFIES);
  
  	atomic_notifier_chain_register(&panic_notifier_list, &panic_block);
  
  	initialized = true;
  
  out:
  	mutex_unlock(&ipmi_interfaces_mutex);
  	return rv;
  }
  
  static int __init ipmi_init_msghandler_mod(void)
  {
  	int rv;
  
  	pr_info("version " IPMI_DRIVER_VERSION "\n");
  
  	mutex_lock(&ipmi_interfaces_mutex);
  	rv = ipmi_register_driver();
  	mutex_unlock(&ipmi_interfaces_mutex);
  
  	return rv;
  }
  
  static void __exit cleanup_ipmi(void)
  {
  	int count;
  
  	if (initialized) {
  		atomic_notifier_chain_unregister(&panic_notifier_list,
  						 &panic_block);
  
  		/*
  		 * This can't be called if any interfaces exist, so no worry
  		 * about shutting down the interfaces.
  		 */
  
  		/*
  		 * Tell the timer to stop, then wait for it to stop.  This
  		 * avoids problems with race conditions removing the timer
  		 * here.
  		 */
  		atomic_set(&stop_operation, 1);
  		del_timer_sync(&ipmi_timer);
  
  		initialized = false;
  
  		/* Check for buffer leaks. */
  		count = atomic_read(&smi_msg_inuse_count);
  		if (count != 0)
  			pr_warn("SMI message count %d at exit\n", count);
  		count = atomic_read(&recv_msg_inuse_count);
  		if (count != 0)
  			pr_warn("recv message count %d at exit\n", count);
  
  		cleanup_srcu_struct(&ipmi_interfaces_srcu);
  	}
  	if (drvregistered)
  		driver_unregister(&ipmidriver.driver);
  }
  module_exit(cleanup_ipmi);
  
  module_init(ipmi_init_msghandler_mod);
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Corey Minyard <minyard@mvista.com>");
  MODULE_DESCRIPTION("Incoming and outgoing message routing for an IPMI"
  		   " interface.");
  MODULE_VERSION(IPMI_DRIVER_VERSION);
  MODULE_SOFTDEP("post: ipmi_devintf");
  