text: /*
   * Serial Attached SCSI (SAS) class SCSI Host glue.
   *
   * Copyright (C) 2005 Adaptec, Inc.  All rights reserved.
   * Copyright (C) 2005 Luben Tuikov <luben_tuikov@adaptec.com>
   *
   * This file is licensed under GPLv2.
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License as
   * published by the Free Software Foundation; either version 2 of the
   * License, or (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
   * USA
   *
   */
  
  #include <linux/kthread.h>
  #include <linux/firmware.h>
  #include <linux/export.h>
  #include <linux/ctype.h>
  #include <linux/kernel.h>
  
  #include "sas_internal.h"
  
  #include <scsi/scsi_host.h>
  #include <scsi/scsi_device.h>
  #include <scsi/scsi_tcq.h>
  #include <scsi/scsi.h>
  #include <scsi/scsi_eh.h>
  #include <scsi/scsi_transport.h>
  #include <scsi/scsi_transport_sas.h>
  #include <scsi/sas_ata.h>
  #include "../scsi_sas_internal.h"
  #include "../scsi_transport_api.h"
  #include "../scsi_priv.h"
  
  #include <linux/err.h>
  #include <linux/blkdev.h>
  #include <linux/freezer.h>
  #include <linux/gfp.h>
  #include <linux/scatterlist.h>
  #include <linux/libata.h>
  
  /* record final status and free the task */
  static void sas_end_task(struct scsi_cmnd *sc, struct sas_task *task)
  {
  	struct task_status_struct *ts = &task->task_status;
  	int hs = 0, stat = 0;
  
  	if (ts->resp == SAS_TASK_UNDELIVERED) {
  		/* transport error */
  		hs = DID_NO_CONNECT;
  	} else { /* ts->resp == SAS_TASK_COMPLETE */
  		/* task delivered, what happened afterwards? */
  		switch (ts->stat) {
  		case SAS_DEV_NO_RESPONSE:
  		case SAS_INTERRUPTED:
  		case SAS_PHY_DOWN:
  		case SAS_NAK_R_ERR:
  		case SAS_OPEN_TO:
  			hs = DID_NO_CONNECT;
  			break;
  		case SAS_DATA_UNDERRUN:
  			scsi_set_resid(sc, ts->residual);
  			if (scsi_bufflen(sc) - scsi_get_resid(sc) < sc->underflow)
  				hs = DID_ERROR;
  			break;
  		case SAS_DATA_OVERRUN:
  			hs = DID_ERROR;
  			break;
  		case SAS_QUEUE_FULL:
  			hs = DID_SOFT_ERROR; /* retry */
  			break;
  		case SAS_DEVICE_UNKNOWN:
  			hs = DID_BAD_TARGET;
  			break;
  		case SAS_SG_ERR:
  			hs = DID_PARITY;
  			break;
  		case SAS_OPEN_REJECT:
  			if (ts->open_rej_reason == SAS_OREJ_RSVD_RETRY)
  				hs = DID_SOFT_ERROR; /* retry */
  			else
  				hs = DID_ERROR;
  			break;
  		case SAS_PROTO_RESPONSE:
  			pr_notice("LLDD:%s sent SAS_PROTO_RESP for an SSP task; please report this\n",
  				  task->dev->port->ha->sas_ha_name);
  			break;
  		case SAS_ABORTED_TASK:
  			hs = DID_ABORT;
  			break;
  		case SAM_STAT_CHECK_CONDITION:
  			memcpy(sc->sense_buffer, ts->buf,
  			       min(SCSI_SENSE_BUFFERSIZE, ts->buf_valid_size));
  			stat = SAM_STAT_CHECK_CONDITION;
  			break;
  		default:
  			stat = ts->stat;
  			break;
  		}
  	}
  
  	sc->result = (hs << 16) | stat;
  	ASSIGN_SAS_TASK(sc, NULL);
  	sas_free_task(task);
  }
  
  static void sas_scsi_task_done(struct sas_task *task)
  {
  	struct scsi_cmnd *sc = task->uldd_task;
  	struct domain_device *dev = task->dev;
  	struct sas_ha_struct *ha = dev->port->ha;
  	unsigned long flags;
  
  	spin_lock_irqsave(&dev->done_lock, flags);
  	if (test_bit(SAS_HA_FROZEN, &ha->state))
  		task = NULL;
  	else
  		ASSIGN_SAS_TASK(sc, NULL);
  	spin_unlock_irqrestore(&dev->done_lock, flags);
  
  	if (unlikely(!task)) {
  		/* task will be completed by the error handler */
  		pr_debug("task done but aborted\n");
  		return;
  	}
  
  	if (unlikely(!sc)) {
  		pr_debug("task_done called with non existing SCSI cmnd!\n");
  		sas_free_task(task);
  		return;
  	}
  
  	sas_end_task(sc, task);
  	sc->scsi_done(sc);
  }
  
  static struct sas_task *sas_create_task(struct scsi_cmnd *cmd,
  					       struct domain_device *dev,
  					       gfp_t gfp_flags)
  {
  	struct sas_task *task = sas_alloc_task(gfp_flags);
  	struct scsi_lun lun;
  
  	if (!task)
  		return NULL;
  
  	task->uldd_task = cmd;
  	ASSIGN_SAS_TASK(cmd, task);
  
  	task->dev = dev;
  	task->task_proto = task->dev->tproto; /* BUG_ON(!SSP) */
  
  	task->ssp_task.retry_count = 1;
  	int_to_scsilun(cmd->device->lun, &lun);
  	memcpy(task->ssp_task.LUN, &lun.scsi_lun, 8);
  	task->ssp_task.task_attr = TASK_ATTR_SIMPLE;
  	task->ssp_task.cmd = cmd;
  
  	task->scatter = scsi_sglist(cmd);
  	task->num_scatter = scsi_sg_count(cmd);
  	task->total_xfer_len = scsi_bufflen(cmd);
  	task->data_dir = cmd->sc_data_direction;
  
  	task->task_done = sas_scsi_task_done;
  
  	return task;
  }
  
  int sas_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)
  {
  	struct sas_internal *i = to_sas_internal(host->transportt);
  	struct domain_device *dev = cmd_to_domain_dev(cmd);
  	struct sas_task *task;
  	int res = 0;
  
  	/* If the device fell off, no sense in issuing commands */
  	if (test_bit(SAS_DEV_GONE, &dev->state)) {
  		cmd->result = DID_BAD_TARGET << 16;
  		goto out_done;
  	}
  
  	if (dev_is_sata(dev)) {
  		spin_lock_irq(dev->sata_dev.ap->lock);
  		res = ata_sas_queuecmd(cmd, dev->sata_dev.ap);
  		spin_unlock_irq(dev->sata_dev.ap->lock);
  		return res;
  	}
  
  	task = sas_create_task(cmd, dev, GFP_ATOMIC);
  	if (!task)
  		return SCSI_MLQUEUE_HOST_BUSY;
  
  	res = i->dft->lldd_execute_task(task, GFP_ATOMIC);
  	if (res)
  		goto out_free_task;
  	return 0;
  
  out_free_task:
  	pr_debug("lldd_execute_task returned: %d\n", res);
  	ASSIGN_SAS_TASK(cmd, NULL);
  	sas_free_task(task);
  	if (res == -SAS_QUEUE_FULL)
  		cmd->result = DID_SOFT_ERROR << 16; /* retry */
  	else
  		cmd->result = DID_ERROR << 16;
  out_done:
  	cmd->scsi_done(cmd);
  	return 0;
  }
  
  static void sas_eh_finish_cmd(struct scsi_cmnd *cmd)
  {
  	struct sas_ha_struct *sas_ha = SHOST_TO_SAS_HA(cmd->device->host);
  	struct domain_device *dev = cmd_to_domain_dev(cmd);
  	struct sas_task *task = TO_SAS_TASK(cmd);
  
  	/* At this point, we only get called following an actual abort
  	 * of the task, so we should be guaranteed not to be racing with
  	 * any completions from the LLD.  Task is freed after this.
  	 */
  	sas_end_task(cmd, task);
  
  	if (dev_is_sata(dev)) {
  		/* defer commands to libata so that libata EH can
  		 * handle ata qcs correctly
  		 */
  		list_move_tail(&cmd->eh_entry, &sas_ha->eh_ata_q);
  		return;
  	}
  
  	/* now finish the command and move it on to the error
  	 * handler done list, this also takes it off the
  	 * error handler pending list.
  	 */
  	scsi_eh_finish_cmd(cmd, &sas_ha->eh_done_q);
  }
  
  static void sas_scsi_clear_queue_lu(struct list_head *error_q, struct scsi_cmnd *my_cmd)
  {
  	struct scsi_cmnd *cmd, *n;
  
  	list_for_each_entry_safe(cmd, n, error_q, eh_entry) {
  		if (cmd->device->sdev_target == my_cmd->device->sdev_target &&
  		    cmd->device->lun == my_cmd->device->lun)
  			sas_eh_finish_cmd(cmd);
  	}
  }
  
  static void sas_scsi_clear_queue_I_T(struct list_head *error_q,
  				     struct domain_device *dev)
  {
  	struct scsi_cmnd *cmd, *n;
  
  	list_for_each_entry_safe(cmd, n, error_q, eh_entry) {
  		struct domain_device *x = cmd_to_domain_dev(cmd);
  
  		if (x == dev)
  			sas_eh_finish_cmd(cmd);
  	}
  }
  
  static void sas_scsi_clear_queue_port(struct list_head *error_q,
  				      struct asd_sas_port *port)
  {
  	struct scsi_cmnd *cmd, *n;
  
  	list_for_each_entry_safe(cmd, n, error_q, eh_entry) {
  		struct domain_device *dev = cmd_to_domain_dev(cmd);
  		struct asd_sas_port *x = dev->port;
  
  		if (x == port)
  			sas_eh_finish_cmd(cmd);
  	}
  }
  
  enum task_disposition {
  	TASK_IS_DONE,
  	TASK_IS_ABORTED,
  	TASK_IS_AT_LU,
  	TASK_IS_NOT_AT_LU,
  	TASK_ABORT_FAILED,
  };
  
  static enum task_disposition sas_scsi_find_task(struct sas_task *task)
  {
  	unsigned long flags;
  	int i, res;
  	struct sas_internal *si =
  		to_sas_internal(task->dev->port->ha->core.shost->transportt);
  
  	for (i = 0; i < 5; i++) {
  		pr_notice("%s: aborting task 0x%p\n", __func__, task);
  		res = si->dft->lldd_abort_task(task);
  
  		spin_lock_irqsave(&task->task_state_lock, flags);
  		if (task->task_state_flags & SAS_TASK_STATE_DONE) {
  			spin_unlock_irqrestore(&task->task_state_lock, flags);
  			pr_debug("%s: task 0x%p is done\n", __func__, task);
  			return TASK_IS_DONE;
  		}
  		spin_unlock_irqrestore(&task->task_state_lock, flags);
  
  		if (res == TMF_RESP_FUNC_COMPLETE) {
  			pr_notice("%s: task 0x%p is aborted\n",
  				  __func__, task);
  			return TASK_IS_ABORTED;
  		} else if (si->dft->lldd_query_task) {
  			pr_notice("%s: querying task 0x%p\n", __func__, task);
  			res = si->dft->lldd_query_task(task);
  			switch (res) {
  			case TMF_RESP_FUNC_SUCC:
  				pr_notice("%s: task 0x%p at LU\n", __func__,
  					  task);
  				return TASK_IS_AT_LU;
  			case TMF_RESP_FUNC_COMPLETE:
  				pr_notice("%s: task 0x%p not at LU\n",
  					  __func__, task);
  				return TASK_IS_NOT_AT_LU;
  			case TMF_RESP_FUNC_FAILED:
  				pr_notice("%s: task 0x%p failed to abort\n",
  					  __func__, task);
  				return TASK_ABORT_FAILED;
  			}
  
  		}
  	}
  	return res;
  }
  
  static int sas_recover_lu(struct domain_device *dev, struct scsi_cmnd *cmd)
  {
  	int res = TMF_RESP_FUNC_FAILED;
  	struct scsi_lun lun;
  	struct sas_internal *i =
  		to_sas_internal(dev->port->ha->core.shost->transportt);
  
  	int_to_scsilun(cmd->device->lun, &lun);
  
  	pr_notice("eh: device %llx LUN %llx has the task\n",
  		  SAS_ADDR(dev->sas_addr),
  		  cmd->device->lun);
  
  	if (i->dft->lldd_abort_task_set)
  		res = i->dft->lldd_abort_task_set(dev, lun.scsi_lun);
  
  	if (res == TMF_RESP_FUNC_FAILED) {
  		if (i->dft->lldd_clear_task_set)
  			res = i->dft->lldd_clear_task_set(dev, lun.scsi_lun);
  	}
  
  	if (res == TMF_RESP_FUNC_FAILED) {
  		if (i->dft->lldd_lu_reset)
  			res = i->dft->lldd_lu_reset(dev, lun.scsi_lun);
  	}
  
  	return res;
  }
  
  static int sas_recover_I_T(struct domain_device *dev)
  {
  	int res = TMF_RESP_FUNC_FAILED;
  	struct sas_internal *i =
  		to_sas_internal(dev->port->ha->core.shost->transportt);
  
  	pr_notice("I_T nexus reset for dev %016llx\n",
  		  SAS_ADDR(dev->sas_addr));
  
  	if (i->dft->lldd_I_T_nexus_reset)
  		res = i->dft->lldd_I_T_nexus_reset(dev);
  
  	return res;
  }
  
  /* take a reference on the last known good phy for this device */
  struct sas_phy *sas_get_local_phy(struct domain_device *dev)
  {
  	struct sas_ha_struct *ha = dev->port->ha;
  	struct sas_phy *phy;
  	unsigned long flags;
  
  	/* a published domain device always has a valid phy, it may be
  	 * stale, but it is never NULL
  	 */
  	BUG_ON(!dev->phy);
  
  	spin_lock_irqsave(&ha->phy_port_lock, flags);
  	phy = dev->phy;
  	get_device(&phy->dev);
  	spin_unlock_irqrestore(&ha->phy_port_lock, flags);
  
  	return phy;
  }
  EXPORT_SYMBOL_GPL(sas_get_local_phy);
  
  static void sas_wait_eh(struct domain_device *dev)
  {
  	struct sas_ha_struct *ha = dev->port->ha;
  	DEFINE_WAIT(wait);
  
  	if (dev_is_sata(dev)) {
  		ata_port_wait_eh(dev->sata_dev.ap);
  		return;
  	}
   retry:
  	spin_lock_irq(&ha->lock);
  
  	while (test_bit(SAS_DEV_EH_PENDING, &dev->state)) {
  		prepare_to_wait(&ha->eh_wait_q, &wait, TASK_UNINTERRUPTIBLE);
  		spin_unlock_irq(&ha->lock);
  		schedule();
  		spin_lock_irq(&ha->lock);
  	}
  	finish_wait(&ha->eh_wait_q, &wait);
  
  	spin_unlock_irq(&ha->lock);
  
  	/* make sure SCSI EH is complete */
  	if (scsi_host_in_recovery(ha->core.shost)) {
  		msleep(10);
  		goto retry;
  	}
  }
  EXPORT_SYMBOL(sas_wait_eh);
  
  static int sas_queue_reset(struct domain_device *dev, int reset_type,
  			   u64 lun, int wait)
  {
  	struct sas_ha_struct *ha = dev->port->ha;
  	int scheduled = 0, tries = 100;
  
  	/* ata: promote lun reset to bus reset */
  	if (dev_is_sata(dev)) {
  		sas_ata_schedule_reset(dev);
  		if (wait)
  			sas_ata_wait_eh(dev);
  		return SUCCESS;
  	}
  
  	while (!scheduled && tries--) {
  		spin_lock_irq(&ha->lock);
  		if (!test_bit(SAS_DEV_EH_PENDING, &dev->state) &&
  		    !test_bit(reset_type, &dev->state)) {
  			scheduled = 1;
  			ha->eh_active++;
  			list_add_tail(&dev->ssp_dev.eh_list_node, &ha->eh_dev_q);
  			set_bit(SAS_DEV_EH_PENDING, &dev->state);
  			set_bit(reset_type, &dev->state);
  			int_to_scsilun(lun, &dev->ssp_dev.reset_lun);
  			scsi_schedule_eh(ha->core.shost);
  		}
  		spin_unlock_irq(&ha->lock);
  
  		if (wait)
  			sas_wait_eh(dev);
  
  		if (scheduled)
  			return SUCCESS;
  	}
  
  	pr_warn("%s reset of %s failed\n",
  		reset_type == SAS_DEV_LU_RESET ? "LUN" : "Bus",
  		dev_name(&dev->rphy->dev));
  
  	return FAILED;
  }
  
  int sas_eh_abort_handler(struct scsi_cmnd *cmd)
  {
  	int res = TMF_RESP_FUNC_FAILED;
  	struct sas_task *task = TO_SAS_TASK(cmd);
  	struct Scsi_Host *host = cmd->device->host;
  	struct domain_device *dev = cmd_to_domain_dev(cmd);
  	struct sas_internal *i = to_sas_internal(host->transportt);
  	unsigned long flags;
  
  	if (!i->dft->lldd_abort_task)
  		return FAILED;
  
  	spin_lock_irqsave(host->host_lock, flags);
  	/* We cannot do async aborts for SATA devices */
  	if (dev_is_sata(dev) && !host->host_eh_scheduled) {
  		spin_unlock_irqrestore(host->host_lock, flags);
  		return FAILED;
  	}
  	spin_unlock_irqrestore(host->host_lock, flags);
  
  	if (task)
  		res = i->dft->lldd_abort_task(task);
  	else
  		pr_notice("no task to abort\n");
  	if (res == TMF_RESP_FUNC_SUCC || res == TMF_RESP_FUNC_COMPLETE)
  		return SUCCESS;
  
  	return FAILED;
  }
  EXPORT_SYMBOL_GPL(sas_eh_abort_handler);
  
  /* Attempt to send a LUN reset message to a device */
  int sas_eh_device_reset_handler(struct scsi_cmnd *cmd)
  {
  	int res;
  	struct scsi_lun lun;
  	struct Scsi_Host *host = cmd->device->host;
  	struct domain_device *dev = cmd_to_domain_dev(cmd);
  	struct sas_internal *i = to_sas_internal(host->transportt);
  
  	if (current != host->ehandler)
  		return sas_queue_reset(dev, SAS_DEV_LU_RESET, cmd->device->lun, 0);
  
  	int_to_scsilun(cmd->device->lun, &lun);
  
  	if (!i->dft->lldd_lu_reset)
  		return FAILED;
  
  	res = i->dft->lldd_lu_reset(dev, lun.scsi_lun);
  	if (res == TMF_RESP_FUNC_SUCC || res == TMF_RESP_FUNC_COMPLETE)
  		return SUCCESS;
  
  	return FAILED;
  }
  
  int sas_eh_target_reset_handler(struct scsi_cmnd *cmd)
  {
  	int res;
  	struct Scsi_Host *host = cmd->device->host;
  	struct domain_device *dev = cmd_to_domain_dev(cmd);
  	struct sas_internal *i = to_sas_internal(host->transportt);
  
  	if (current != host->ehandler)
  		return sas_queue_reset(dev, SAS_DEV_RESET, 0, 0);
  
  	if (!i->dft->lldd_I_T_nexus_reset)
  		return FAILED;
  
  	res = i->dft->lldd_I_T_nexus_reset(dev);
  	if (res == TMF_RESP_FUNC_SUCC || res == TMF_RESP_FUNC_COMPLETE ||
  	    res == -ENODEV)
  		return SUCCESS;
  
  	return FAILED;
  }
  
  /* Try to reset a device */
  static int try_to_reset_cmd_device(struct scsi_cmnd *cmd)
  {
  	int res;
  	struct Scsi_Host *shost = cmd->device->host;
  
  	if (!shost->hostt->eh_device_reset_handler)
  		goto try_target_reset;
  
  	res = shost->hostt->eh_device_reset_handler(cmd);
  	if (res == SUCCESS)
  		return res;
  
  try_target_reset:
  	if (shost->hostt->eh_target_reset_handler)
  		return shost->hostt->eh_target_reset_handler(cmd);
  
  	return FAILED;
  }
  
  static void sas_eh_handle_sas_errors(struct Scsi_Host *shost, struct list_head *work_q)
  {
  	struct scsi_cmnd *cmd, *n;
  	enum task_disposition res = TASK_IS_DONE;
  	int tmf_resp, need_reset;
  	struct sas_internal *i = to_sas_internal(shost->transportt);
  	unsigned long flags;
  	struct sas_ha_struct *ha = SHOST_TO_SAS_HA(shost);
  	LIST_HEAD(done);
  
  	/* clean out any commands that won the completion vs eh race */
  	list_for_each_entry_safe(cmd, n, work_q, eh_entry) {
  		struct domain_device *dev = cmd_to_domain_dev(cmd);
  		struct sas_task *task;
  
  		spin_lock_irqsave(&dev->done_lock, flags);
  		/* by this point the lldd has either observed
  		 * SAS_HA_FROZEN and is leaving the task alone, or has
  		 * won the race with eh and decided to complete it
  		 */
  		task = TO_SAS_TASK(cmd);
  		spin_unlock_irqrestore(&dev->done_lock, flags);
  
  		if (!task)
  			list_move_tail(&cmd->eh_entry, &done);
  	}
  
   Again:
  	list_for_each_entry_safe(cmd, n, work_q, eh_entry) {
  		struct sas_task *task = TO_SAS_TASK(cmd);
  
  		list_del_init(&cmd->eh_entry);
  
  		spin_lock_irqsave(&task->task_state_lock, flags);
  		need_reset = task->task_state_flags & SAS_TASK_NEED_DEV_RESET;
  		spin_unlock_irqrestore(&task->task_state_lock, flags);
  
  		if (need_reset) {
  			pr_notice("%s: task 0x%p requests reset\n",
  				  __func__, task);
  			goto reset;
  		}
  
  		pr_debug("trying to find task 0x%p\n", task);
  		res = sas_scsi_find_task(task);
  
  		switch (res) {
  		case TASK_IS_DONE:
  			pr_notice("%s: task 0x%p is done\n", __func__,
  				    task);
  			sas_eh_finish_cmd(cmd);
  			continue;
  		case TASK_IS_ABORTED:
  			pr_notice("%s: task 0x%p is aborted\n",
  				  __func__, task);
  			sas_eh_finish_cmd(cmd);
  			continue;
  		case TASK_IS_AT_LU:
  			pr_info("task 0x%p is at LU: lu recover\n", task);
   reset:
  			tmf_resp = sas_recover_lu(task->dev, cmd);
  			if (tmf_resp == TMF_RESP_FUNC_COMPLETE) {
  				pr_notice("dev %016llx LU %llx is recovered\n",
  					  SAS_ADDR(task->dev),
  					  cmd->device->lun);
  				sas_eh_finish_cmd(cmd);
  				sas_scsi_clear_queue_lu(work_q, cmd);
  				goto Again;
  			}
  			/* fallthrough */
  		case TASK_IS_NOT_AT_LU:
  		case TASK_ABORT_FAILED:
  			pr_notice("task 0x%p is not at LU: I_T recover\n",
  				  task);
  			tmf_resp = sas_recover_I_T(task->dev);
  			if (tmf_resp == TMF_RESP_FUNC_COMPLETE ||
  			    tmf_resp == -ENODEV) {
  				struct domain_device *dev = task->dev;
  				pr_notice("I_T %016llx recovered\n",
  					  SAS_ADDR(task->dev->sas_addr));
  				sas_eh_finish_cmd(cmd);
  				sas_scsi_clear_queue_I_T(work_q, dev);
  				goto Again;
  			}
  			/* Hammer time :-) */
  			try_to_reset_cmd_device(cmd);
  			if (i->dft->lldd_clear_nexus_port) {
  				struct asd_sas_port *port = task->dev->port;
  				pr_debug("clearing nexus for port:%d\n",
  					  port->id);
  				res = i->dft->lldd_clear_nexus_port(port);
  				if (res == TMF_RESP_FUNC_COMPLETE) {
  					pr_notice("clear nexus port:%d succeeded\n",
  						  port->id);
  					sas_eh_finish_cmd(cmd);
  					sas_scsi_clear_queue_port(work_q,
  								  port);
  					goto Again;
  				}
  			}
  			if (i->dft->lldd_clear_nexus_ha) {
  				pr_debug("clear nexus ha\n");
  				res = i->dft->lldd_clear_nexus_ha(ha);
  				if (res == TMF_RESP_FUNC_COMPLETE) {
  					pr_notice("clear nexus ha succeeded\n");
  					sas_eh_finish_cmd(cmd);
  					goto clear_q;
  				}
  			}
  			/* If we are here -- this means that no amount
  			 * of effort could recover from errors.  Quite
  			 * possibly the HA just disappeared.
  			 */
  			pr_err("error from  device %llx, LUN %llx couldn't be recovered in any way\n",
  			       SAS_ADDR(task->dev->sas_addr),
  			       cmd->device->lun);
  
  			sas_eh_finish_cmd(cmd);
  			goto clear_q;
  		}
  	}
   out:
  	list_splice_tail(&done, work_q);
  	list_splice_tail_init(&ha->eh_ata_q, work_q);
  	return;
  
   clear_q:
  	pr_debug("--- Exit %s -- clear_q\n", __func__);
  	list_for_each_entry_safe(cmd, n, work_q, eh_entry)
  		sas_eh_finish_cmd(cmd);
  	goto out;
  }
  
  static void sas_eh_handle_resets(struct Scsi_Host *shost)
  {
  	struct sas_ha_struct *ha = SHOST_TO_SAS_HA(shost);
  	struct sas_internal *i = to_sas_internal(shost->transportt);
  
  	/* handle directed resets to sas devices */
  	spin_lock_irq(&ha->lock);
  	while (!list_empty(&ha->eh_dev_q)) {
  		struct domain_device *dev;
  		struct ssp_device *ssp;
  
  		ssp = list_entry(ha->eh_dev_q.next, typeof(*ssp), eh_list_node);
  		list_del_init(&ssp->eh_list_node);
  		dev = container_of(ssp, typeof(*dev), ssp_dev);
  		kref_get(&dev->kref);
  		WARN_ONCE(dev_is_sata(dev), "ssp reset to ata device?\n");
  
  		spin_unlock_irq(&ha->lock);
  
  		if (test_and_clear_bit(SAS_DEV_LU_RESET, &dev->state))
  			i->dft->lldd_lu_reset(dev, ssp->reset_lun.scsi_lun);
  
  		if (test_and_clear_bit(SAS_DEV_RESET, &dev->state))
  			i->dft->lldd_I_T_nexus_reset(dev);
  
  		sas_put_device(dev);
  		spin_lock_irq(&ha->lock);
  		clear_bit(SAS_DEV_EH_PENDING, &dev->state);
  		ha->eh_active--;
  	}
  	spin_unlock_irq(&ha->lock);
  }
  
  
  void sas_scsi_recover_host(struct Scsi_Host *shost)
  {
  	struct sas_ha_struct *ha = SHOST_TO_SAS_HA(shost);
  	LIST_HEAD(eh_work_q);
  	int tries = 0;
  	bool retry;
  
  retry:
  	tries++;
  	retry = true;
  	spin_lock_irq(shost->host_lock);
  	list_splice_init(&shost->eh_cmd_q, &eh_work_q);
  	spin_unlock_irq(shost->host_lock);
  
  	pr_notice("Enter %s busy: %d failed: %d\n",
  		  __func__, scsi_host_busy(shost), shost->host_failed);
  	/*
  	 * Deal with commands that still have SAS tasks (i.e. they didn't
  	 * complete via the normal sas_task completion mechanism),
  	 * SAS_HA_FROZEN gives eh dominion over all sas_task completion.
  	 */
  	set_bit(SAS_HA_FROZEN, &ha->state);
  	sas_eh_handle_sas_errors(shost, &eh_work_q);
  	clear_bit(SAS_HA_FROZEN, &ha->state);
  	if (list_empty(&eh_work_q))
  		goto out;
  
  	/*
  	 * Now deal with SCSI commands that completed ok but have a an error
  	 * code (and hopefully sense data) attached.  This is roughly what
  	 * scsi_unjam_host does, but we skip scsi_eh_abort_cmds because any
  	 * command we see here has no sas_task and is thus unknown to the HA.
  	 */
  	sas_ata_eh(shost, &eh_work_q, &ha->eh_done_q);
  	if (!scsi_eh_get_sense(&eh_work_q, &ha->eh_done_q))
  		scsi_eh_ready_devs(shost, &eh_work_q, &ha->eh_done_q);
  
  out:
  	sas_eh_handle_resets(shost);
  
  	/* now link into libata eh --- if we have any ata devices */
  	sas_ata_strategy_handler(shost);
  
  	scsi_eh_flush_done_q(&ha->eh_done_q);
  
  	/* check if any new eh work was scheduled during the last run */
  	spin_lock_irq(&ha->lock);
  	if (ha->eh_active == 0) {
  		shost->host_eh_scheduled = 0;
  		retry = false;
  	}
  	spin_unlock_irq(&ha->lock);
  
  	if (retry)
  		goto retry;
  
  	pr_notice("--- Exit %s: busy: %d failed: %d tries: %d\n",
  		  __func__, scsi_host_busy(shost),
  		  shost->host_failed, tries);
  }
  
  int sas_ioctl(struct scsi_device *sdev, unsigned int cmd, void __user *arg)
  {
  	struct domain_device *dev = sdev_to_domain_dev(sdev);
  
  	if (dev_is_sata(dev))
  		return ata_sas_scsi_ioctl(dev->sata_dev.ap, sdev, cmd, arg);
  
  	return -EINVAL;
  }
  
  struct domain_device *sas_find_dev_by_rphy(struct sas_rphy *rphy)
  {
  	struct Scsi_Host *shost = dev_to_shost(rphy->dev.parent);
  	struct sas_ha_struct *ha = SHOST_TO_SAS_HA(shost);
  	struct domain_device *found_dev = NULL;
  	int i;
  	unsigned long flags;
  
  	spin_lock_irqsave(&ha->phy_port_lock, flags);
  	for (i = 0; i < ha->num_phys; i++) {
  		struct asd_sas_port *port = ha->sas_port[i];
  		struct domain_device *dev;
  
  		spin_lock(&port->dev_list_lock);
  		list_for_each_entry(dev, &port->dev_list, dev_list_node) {
  			if (rphy == dev->rphy) {
  				found_dev = dev;
  				spin_unlock(&port->dev_list_lock);
  				goto found;
  			}
  		}
  		spin_unlock(&port->dev_list_lock);
  	}
   found:
  	spin_unlock_irqrestore(&ha->phy_port_lock, flags);
  
  	return found_dev;
  }
  
  int sas_target_alloc(struct scsi_target *starget)
  {
  	struct sas_rphy *rphy = dev_to_rphy(starget->dev.parent);
  	struct domain_device *found_dev = sas_find_dev_by_rphy(rphy);
  
  	if (!found_dev)
  		return -ENODEV;
  
  	kref_get(&found_dev->kref);
  	starget->hostdata = found_dev;
  	return 0;
  }
  
  #define SAS_DEF_QD 256
  
  int sas_slave_configure(struct scsi_device *scsi_dev)
  {
  	struct domain_device *dev = sdev_to_domain_dev(scsi_dev);
  
  	BUG_ON(dev->rphy->identify.device_type != SAS_END_DEVICE);
  
  	if (dev_is_sata(dev)) {
  		ata_sas_slave_configure(scsi_dev, dev->sata_dev.ap);
  		return 0;
  	}
  
  	sas_read_port_mode_page(scsi_dev);
  
  	if (scsi_dev->tagged_supported) {
  		scsi_change_queue_depth(scsi_dev, SAS_DEF_QD);
  	} else {
  		pr_notice("device %llx, LUN %llx doesn't support TCQ\n",
  			  SAS_ADDR(dev->sas_addr), scsi_dev->lun);
  		scsi_change_queue_depth(scsi_dev, 1);
  	}
  
  	scsi_dev->allow_restart = 1;
  
  	return 0;
  }
  
  int sas_change_queue_depth(struct scsi_device *sdev, int depth)
  {
  	struct domain_device *dev = sdev_to_domain_dev(sdev);
  
  	if (dev_is_sata(dev))
  		return __ata_change_queue_depth(dev->sata_dev.ap, sdev, depth);
  
  	if (!sdev->tagged_supported)
  		depth = 1;
  	return scsi_change_queue_depth(sdev, depth);
  }
  
  int sas_bios_param(struct scsi_device *scsi_dev,
  			  struct block_device *bdev,
  			  sector_t capacity, int *hsc)
  {
  	hsc[0] = 255;
  	hsc[1] = 63;
  	sector_div(capacity, 255*63);
  	hsc[2] = capacity;
  
  	return 0;
  }
  
  /*
   * Tell an upper layer that it needs to initiate an abort for a given task.
   * This should only ever be called by an LLDD.
   */
  void sas_task_abort(struct sas_task *task)
  {
  	struct scsi_cmnd *sc = task->uldd_task;
  
  	/* Escape for libsas internal commands */
  	if (!sc) {
  		struct sas_task_slow *slow = task->slow_task;
  
  		if (!slow)
  			return;
  		if (!del_timer(&slow->timer))
  			return;
  		slow->timer.function(&slow->timer);
  		return;
  	}
  
  	if (dev_is_sata(task->dev))
  		sas_ata_task_abort(task);
  	else
  		blk_abort_request(sc->request);
  }
  
  void sas_target_destroy(struct scsi_target *starget)
  {
  	struct domain_device *found_dev = starget->hostdata;
  
  	if (!found_dev)
  		return;
  
  	starget->hostdata = NULL;
  	sas_put_device(found_dev);
  }
  
  #define SAS_STRING_ADDR_SIZE	16
  
  int sas_request_addr(struct Scsi_Host *shost, u8 *addr)
  {
  	int res;
  	const struct firmware *fw;
  
  	res = request_firmware(&fw, "sas_addr", &shost->shost_gendev);
  	if (res)
  		return res;
  
  	if (fw->size < SAS_STRING_ADDR_SIZE) {
  		res = -ENODEV;
  		goto out;
  	}
  
  	res = hex2bin(addr, fw->data, strnlen(fw->data, SAS_ADDR_SIZE * 2) / 2);
  	if (res)
  		goto out;
  
  out:
  	release_firmware(fw);
  	return res;
  }
  EXPORT_SYMBOL_GPL(sas_request_addr);
  
  EXPORT_SYMBOL_GPL(sas_queuecommand);
  EXPORT_SYMBOL_GPL(sas_target_alloc);
  EXPORT_SYMBOL_GPL(sas_slave_configure);
  EXPORT_SYMBOL_GPL(sas_change_queue_depth);
  EXPORT_SYMBOL_GPL(sas_bios_param);
  EXPORT_SYMBOL_GPL(sas_task_abort);
  EXPORT_SYMBOL_GPL(sas_phy_reset);
  EXPORT_SYMBOL_GPL(sas_eh_device_reset_handler);
  EXPORT_SYMBOL_GPL(sas_eh_target_reset_handler);
  EXPORT_SYMBOL_GPL(sas_target_destroy);
  EXPORT_SYMBOL_GPL(sas_ioctl);
  