text: /*
   * Copyright (c) 2005 Topspin Communications.  All rights reserved.
   * Copyright (c) 2005, 2006 Cisco Systems.  All rights reserved.
   * Copyright (c) 2005 Mellanox Technologies. All rights reserved.
   * Copyright (c) 2005 Voltaire, Inc. All rights reserved.
   * Copyright (c) 2005 PathScale, Inc. All rights reserved.
   *
   * This software is available to you under a choice of one of two
   * licenses.  You may choose to be licensed under the terms of the GNU
   * General Public License (GPL) Version 2, available from the file
   * COPYING in the main directory of this source tree, or the
   * OpenIB.org BSD license below:
   *
   *     Redistribution and use in source and binary forms, with or
   *     without modification, are permitted provided that the following
   *     conditions are met:
   *
   *      - Redistributions of source code must retain the above
   *        copyright notice, this list of conditions and the following
   *        disclaimer.
   *
   *      - Redistributions in binary form must reproduce the above
   *        copyright notice, this list of conditions and the following
   *        disclaimer in the documentation and/or other materials
   *        provided with the distribution.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
   * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
   * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
   * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
   * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   */
  
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/device.h>
  #include <linux/err.h>
  #include <linux/fs.h>
  #include <linux/poll.h>
  #include <linux/sched.h>
  #include <linux/file.h>
  #include <linux/cdev.h>
  #include <linux/anon_inodes.h>
  #include <linux/slab.h>
  
  #include <linux/uaccess.h>
  
  #include <rdma/ib.h>
  
  #include "uverbs.h"
  #include "core_priv.h"
  
  MODULE_AUTHOR("Roland Dreier");
  MODULE_DESCRIPTION("InfiniBand userspace verbs access");
  MODULE_LICENSE("Dual BSD/GPL");
  
  enum {
  	IB_UVERBS_MAJOR       = 231,
  	IB_UVERBS_BASE_MINOR  = 192,
  	IB_UVERBS_MAX_DEVICES = 32
  };
  
  #define IB_UVERBS_BASE_DEV	MKDEV(IB_UVERBS_MAJOR, IB_UVERBS_BASE_MINOR)
  
  static struct class *uverbs_class;
  
  DEFINE_SPINLOCK(ib_uverbs_idr_lock);
  DEFINE_IDR(ib_uverbs_pd_idr);
  DEFINE_IDR(ib_uverbs_mr_idr);
  DEFINE_IDR(ib_uverbs_mw_idr);
  DEFINE_IDR(ib_uverbs_ah_idr);
  DEFINE_IDR(ib_uverbs_cq_idr);
  DEFINE_IDR(ib_uverbs_qp_idr);
  DEFINE_IDR(ib_uverbs_srq_idr);
  DEFINE_IDR(ib_uverbs_xrcd_idr);
  DEFINE_IDR(ib_uverbs_rule_idr);
  DEFINE_IDR(ib_uverbs_wq_idr);
  DEFINE_IDR(ib_uverbs_rwq_ind_tbl_idr);
  
  static DEFINE_SPINLOCK(map_lock);
  static DECLARE_BITMAP(dev_map, IB_UVERBS_MAX_DEVICES);
  
  static ssize_t (*uverbs_cmd_table[])(struct ib_uverbs_file *file,
  				     struct ib_device *ib_dev,
  				     const char __user *buf, int in_len,
  				     int out_len) = {
  	[IB_USER_VERBS_CMD_GET_CONTEXT]		= ib_uverbs_get_context,
  	[IB_USER_VERBS_CMD_QUERY_DEVICE]	= ib_uverbs_query_device,
  	[IB_USER_VERBS_CMD_QUERY_PORT]		= ib_uverbs_query_port,
  	[IB_USER_VERBS_CMD_ALLOC_PD]		= ib_uverbs_alloc_pd,
  	[IB_USER_VERBS_CMD_DEALLOC_PD]		= ib_uverbs_dealloc_pd,
  	[IB_USER_VERBS_CMD_REG_MR]		= ib_uverbs_reg_mr,
  	[IB_USER_VERBS_CMD_REREG_MR]		= ib_uverbs_rereg_mr,
  	[IB_USER_VERBS_CMD_DEREG_MR]		= ib_uverbs_dereg_mr,
  	[IB_USER_VERBS_CMD_ALLOC_MW]		= ib_uverbs_alloc_mw,
  	[IB_USER_VERBS_CMD_DEALLOC_MW]		= ib_uverbs_dealloc_mw,
  	[IB_USER_VERBS_CMD_CREATE_COMP_CHANNEL] = ib_uverbs_create_comp_channel,
  	[IB_USER_VERBS_CMD_CREATE_CQ]		= ib_uverbs_create_cq,
  	[IB_USER_VERBS_CMD_RESIZE_CQ]		= ib_uverbs_resize_cq,
  	[IB_USER_VERBS_CMD_POLL_CQ]		= ib_uverbs_poll_cq,
  	[IB_USER_VERBS_CMD_REQ_NOTIFY_CQ]	= ib_uverbs_req_notify_cq,
  	[IB_USER_VERBS_CMD_DESTROY_CQ]		= ib_uverbs_destroy_cq,
  	[IB_USER_VERBS_CMD_CREATE_QP]		= ib_uverbs_create_qp,
  	[IB_USER_VERBS_CMD_QUERY_QP]		= ib_uverbs_query_qp,
  	[IB_USER_VERBS_CMD_MODIFY_QP]		= ib_uverbs_modify_qp,
  	[IB_USER_VERBS_CMD_DESTROY_QP]		= ib_uverbs_destroy_qp,
  	[IB_USER_VERBS_CMD_POST_SEND]		= ib_uverbs_post_send,
  	[IB_USER_VERBS_CMD_POST_RECV]		= ib_uverbs_post_recv,
  	[IB_USER_VERBS_CMD_POST_SRQ_RECV]	= ib_uverbs_post_srq_recv,
  	[IB_USER_VERBS_CMD_CREATE_AH]		= ib_uverbs_create_ah,
  	[IB_USER_VERBS_CMD_DESTROY_AH]		= ib_uverbs_destroy_ah,
  	[IB_USER_VERBS_CMD_ATTACH_MCAST]	= ib_uverbs_attach_mcast,
  	[IB_USER_VERBS_CMD_DETACH_MCAST]	= ib_uverbs_detach_mcast,
  	[IB_USER_VERBS_CMD_CREATE_SRQ]		= ib_uverbs_create_srq,
  	[IB_USER_VERBS_CMD_MODIFY_SRQ]		= ib_uverbs_modify_srq,
  	[IB_USER_VERBS_CMD_QUERY_SRQ]		= ib_uverbs_query_srq,
  	[IB_USER_VERBS_CMD_DESTROY_SRQ]		= ib_uverbs_destroy_srq,
  	[IB_USER_VERBS_CMD_OPEN_XRCD]		= ib_uverbs_open_xrcd,
  	[IB_USER_VERBS_CMD_CLOSE_XRCD]		= ib_uverbs_close_xrcd,
  	[IB_USER_VERBS_CMD_CREATE_XSRQ]		= ib_uverbs_create_xsrq,
  	[IB_USER_VERBS_CMD_OPEN_QP]		= ib_uverbs_open_qp,
  };
  
  static int (*uverbs_ex_cmd_table[])(struct ib_uverbs_file *file,
  				    struct ib_device *ib_dev,
  				    struct ib_udata *ucore,
  				    struct ib_udata *uhw) = {
  	[IB_USER_VERBS_EX_CMD_CREATE_FLOW]	= ib_uverbs_ex_create_flow,
  	[IB_USER_VERBS_EX_CMD_DESTROY_FLOW]	= ib_uverbs_ex_destroy_flow,
  	[IB_USER_VERBS_EX_CMD_QUERY_DEVICE]	= ib_uverbs_ex_query_device,
  	[IB_USER_VERBS_EX_CMD_CREATE_CQ]	= ib_uverbs_ex_create_cq,
  	[IB_USER_VERBS_EX_CMD_CREATE_QP]        = ib_uverbs_ex_create_qp,
  	[IB_USER_VERBS_EX_CMD_CREATE_WQ]        = ib_uverbs_ex_create_wq,
  	[IB_USER_VERBS_EX_CMD_MODIFY_WQ]        = ib_uverbs_ex_modify_wq,
  	[IB_USER_VERBS_EX_CMD_DESTROY_WQ]       = ib_uverbs_ex_destroy_wq,
  	[IB_USER_VERBS_EX_CMD_CREATE_RWQ_IND_TBL] = ib_uverbs_ex_create_rwq_ind_table,
  	[IB_USER_VERBS_EX_CMD_DESTROY_RWQ_IND_TBL] = ib_uverbs_ex_destroy_rwq_ind_table,
  	[IB_USER_VERBS_EX_CMD_MODIFY_QP]        = ib_uverbs_ex_modify_qp,
  };
  
  static void ib_uverbs_add_one(struct ib_device *device);
  static void ib_uverbs_remove_one(struct ib_device *device, void *client_data);
  
  int uverbs_dealloc_mw(struct ib_mw *mw)
  {
  	struct ib_pd *pd = mw->pd;
  	int ret;
  
  	ret = mw->device->dealloc_mw(mw);
  	if (!ret)
  		atomic_dec(&pd->usecnt);
  	return ret;
  }
  
  static void ib_uverbs_release_dev(struct kobject *kobj)
  {
  	struct ib_uverbs_device *dev =
  		container_of(kobj, struct ib_uverbs_device, kobj);
  
  	cleanup_srcu_struct(&dev->disassociate_srcu);
  	kfree(dev);
  }
  
  static struct kobj_type ib_uverbs_dev_ktype = {
  	.release = ib_uverbs_release_dev,
  };
  
  static void ib_uverbs_release_event_file(struct kref *ref)
  {
  	struct ib_uverbs_event_file *file =
  		container_of(ref, struct ib_uverbs_event_file, ref);
  
  	kfree(file);
  }
  
  void ib_uverbs_release_ucq(struct ib_uverbs_file *file,
  			  struct ib_uverbs_event_file *ev_file,
  			  struct ib_ucq_object *uobj)
  {
  	struct ib_uverbs_event *evt, *tmp;
  
  	if (ev_file) {
  		spin_lock_irq(&ev_file->lock);
  		list_for_each_entry_safe(evt, tmp, &uobj->comp_list, obj_list) {
  			list_del(&evt->list);
  			kfree(evt);
  		}
  		spin_unlock_irq(&ev_file->lock);
  
  		kref_put(&ev_file->ref, ib_uverbs_release_event_file);
  	}
  
  	spin_lock_irq(&file->async_file->lock);
  	list_for_each_entry_safe(evt, tmp, &uobj->async_list, obj_list) {
  		list_del(&evt->list);
  		kfree(evt);
  	}
  	spin_unlock_irq(&file->async_file->lock);
  }
  
  void ib_uverbs_release_uevent(struct ib_uverbs_file *file,
  			      struct ib_uevent_object *uobj)
  {
  	struct ib_uverbs_event *evt, *tmp;
  
  	spin_lock_irq(&file->async_file->lock);
  	list_for_each_entry_safe(evt, tmp, &uobj->event_list, obj_list) {
  		list_del(&evt->list);
  		kfree(evt);
  	}
  	spin_unlock_irq(&file->async_file->lock);
  }
  
  static void ib_uverbs_detach_umcast(struct ib_qp *qp,
  				    struct ib_uqp_object *uobj)
  {
  	struct ib_uverbs_mcast_entry *mcast, *tmp;
  
  	list_for_each_entry_safe(mcast, tmp, &uobj->mcast_list, list) {
  		ib_detach_mcast(qp, &mcast->gid, mcast->lid);
  		list_del(&mcast->list);
  		kfree(mcast);
  	}
  }
  
  static int ib_uverbs_cleanup_ucontext(struct ib_uverbs_file *file,
  				      struct ib_ucontext *context)
  {
  	struct ib_uobject *uobj, *tmp;
  
  	context->closing = 1;
  
  	list_for_each_entry_safe(uobj, tmp, &context->ah_list, list) {
  		struct ib_ah *ah = uobj->object;
  
  		idr_remove_uobj(&ib_uverbs_ah_idr, uobj);
  		ib_destroy_ah(ah);
  		ib_rdmacg_uncharge(&uobj->cg_obj, context->device,
  				   RDMACG_RESOURCE_HCA_OBJECT);
  		kfree(uobj);
  	}
  
  	/* Remove MWs before QPs, in order to support type 2A MWs. */
  	list_for_each_entry_safe(uobj, tmp, &context->mw_list, list) {
  		struct ib_mw *mw = uobj->object;
  
  		idr_remove_uobj(&ib_uverbs_mw_idr, uobj);
  		uverbs_dealloc_mw(mw);
  		ib_rdmacg_uncharge(&uobj->cg_obj, context->device,
  				   RDMACG_RESOURCE_HCA_OBJECT);
  		kfree(uobj);
  	}
  
  	list_for_each_entry_safe(uobj, tmp, &context->rule_list, list) {
  		struct ib_flow *flow_id = uobj->object;
  
  		idr_remove_uobj(&ib_uverbs_rule_idr, uobj);
  		ib_destroy_flow(flow_id);
  		ib_rdmacg_uncharge(&uobj->cg_obj, context->device,
  				   RDMACG_RESOURCE_HCA_OBJECT);
  		kfree(uobj);
  	}
  
  	list_for_each_entry_safe(uobj, tmp, &context->qp_list, list) {
  		struct ib_qp *qp = uobj->object;
  		struct ib_uqp_object *uqp =
  			container_of(uobj, struct ib_uqp_object, uevent.uobject);
  
  		idr_remove_uobj(&ib_uverbs_qp_idr, uobj);
  		if (qp == qp->real_qp)
  			ib_uverbs_detach_umcast(qp, uqp);
  		ib_destroy_qp(qp);
  		ib_rdmacg_uncharge(&uobj->cg_obj, context->device,
  				   RDMACG_RESOURCE_HCA_OBJECT);
  		ib_uverbs_release_uevent(file, &uqp->uevent);
  		kfree(uqp);
  	}
  
  	list_for_each_entry_safe(uobj, tmp, &context->rwq_ind_tbl_list, list) {
  		struct ib_rwq_ind_table *rwq_ind_tbl = uobj->object;
  		struct ib_wq **ind_tbl = rwq_ind_tbl->ind_tbl;
  
  		idr_remove_uobj(&ib_uverbs_rwq_ind_tbl_idr, uobj);
  		ib_destroy_rwq_ind_table(rwq_ind_tbl);
  		kfree(ind_tbl);
  		kfree(uobj);
  	}
  
  	list_for_each_entry_safe(uobj, tmp, &context->wq_list, list) {
  		struct ib_wq *wq = uobj->object;
  		struct ib_uwq_object *uwq =
  			container_of(uobj, struct ib_uwq_object, uevent.uobject);
  
  		idr_remove_uobj(&ib_uverbs_wq_idr, uobj);
  		ib_destroy_wq(wq);
  		ib_uverbs_release_uevent(file, &uwq->uevent);
  		kfree(uwq);
  	}
  
  	list_for_each_entry_safe(uobj, tmp, &context->srq_list, list) {
  		struct ib_srq *srq = uobj->object;
  		struct ib_uevent_object *uevent =
  			container_of(uobj, struct ib_uevent_object, uobject);
  
  		idr_remove_uobj(&ib_uverbs_srq_idr, uobj);
  		ib_destroy_srq(srq);
  		ib_rdmacg_uncharge(&uobj->cg_obj, context->device,
  				   RDMACG_RESOURCE_HCA_OBJECT);
  		ib_uverbs_release_uevent(file, uevent);
  		kfree(uevent);
  	}
  
  	list_for_each_entry_safe(uobj, tmp, &context->cq_list, list) {
  		struct ib_cq *cq = uobj->object;
  		struct ib_uverbs_event_file *ev_file = cq->cq_context;
  		struct ib_ucq_object *ucq =
  			container_of(uobj, struct ib_ucq_object, uobject);
  
  		idr_remove_uobj(&ib_uverbs_cq_idr, uobj);
  		ib_destroy_cq(cq);
  		ib_rdmacg_uncharge(&uobj->cg_obj, context->device,
  				   RDMACG_RESOURCE_HCA_OBJECT);
  		ib_uverbs_release_ucq(file, ev_file, ucq);
  		kfree(ucq);
  	}
  
  	list_for_each_entry_safe(uobj, tmp, &context->mr_list, list) {
  		struct ib_mr *mr = uobj->object;
  
  		idr_remove_uobj(&ib_uverbs_mr_idr, uobj);
  		ib_dereg_mr(mr);
  		ib_rdmacg_uncharge(&uobj->cg_obj, context->device,
  				   RDMACG_RESOURCE_HCA_OBJECT);
  		kfree(uobj);
  	}
  
  	mutex_lock(&file->device->xrcd_tree_mutex);
  	list_for_each_entry_safe(uobj, tmp, &context->xrcd_list, list) {
  		struct ib_xrcd *xrcd = uobj->object;
  		struct ib_uxrcd_object *uxrcd =
  			container_of(uobj, struct ib_uxrcd_object, uobject);
  
  		idr_remove_uobj(&ib_uverbs_xrcd_idr, uobj);
  		ib_uverbs_dealloc_xrcd(file->device, xrcd);
  		kfree(uxrcd);
  	}
  	mutex_unlock(&file->device->xrcd_tree_mutex);
  
  	list_for_each_entry_safe(uobj, tmp, &context->pd_list, list) {
  		struct ib_pd *pd = uobj->object;
  
  		idr_remove_uobj(&ib_uverbs_pd_idr, uobj);
  		ib_dealloc_pd(pd);
  		ib_rdmacg_uncharge(&uobj->cg_obj, context->device,
  				   RDMACG_RESOURCE_HCA_OBJECT);
  		kfree(uobj);
  	}
  
  	put_pid(context->tgid);
  
  	ib_rdmacg_uncharge(&context->cg_obj, context->device,
  			   RDMACG_RESOURCE_HCA_HANDLE);
  
  	return context->device->dealloc_ucontext(context);
  }
  
  static void ib_uverbs_comp_dev(struct ib_uverbs_device *dev)
  {
  	complete(&dev->comp);
  }
  
  static void ib_uverbs_release_file(struct kref *ref)
  {
  	struct ib_uverbs_file *file =
  		container_of(ref, struct ib_uverbs_file, ref);
  	struct ib_device *ib_dev;
  	int srcu_key;
  
  	srcu_key = srcu_read_lock(&file->device->disassociate_srcu);
  	ib_dev = srcu_dereference(file->device->ib_dev,
  				  &file->device->disassociate_srcu);
  	if (ib_dev && !ib_dev->disassociate_ucontext)
  		module_put(ib_dev->owner);
  	srcu_read_unlock(&file->device->disassociate_srcu, srcu_key);
  
  	if (atomic_dec_and_test(&file->device->refcount))
  		ib_uverbs_comp_dev(file->device);
  
  	kfree(file);
  }
  
  static ssize_t ib_uverbs_event_read(struct file *filp, char __user *buf,
  				    size_t count, loff_t *pos)
  {
  	struct ib_uverbs_event_file *file = filp->private_data;
  	struct ib_uverbs_event *event;
  	int eventsz;
  	int ret = 0;
  
  	spin_lock_irq(&file->lock);
  
  	while (list_empty(&file->event_list)) {
  		spin_unlock_irq(&file->lock);
  
  		if (filp->f_flags & O_NONBLOCK)
  			return -EAGAIN;
  
  		if (wait_event_interruptible(file->poll_wait,
  					     (!list_empty(&file->event_list) ||
  			/* The barriers built into wait_event_interruptible()
  			 * and wake_up() guarentee this will see the null set
  			 * without using RCU
  			 */
  					     !file->uverbs_file->device->ib_dev)))
  			return -ERESTARTSYS;
  
  		/* If device was disassociated and no event exists set an error */
  		if (list_empty(&file->event_list) &&
  		    !file->uverbs_file->device->ib_dev)
  			return -EIO;
  
  		spin_lock_irq(&file->lock);
  	}
  
  	event = list_entry(file->event_list.next, struct ib_uverbs_event, list);
  
  	if (file->is_async)
  		eventsz = sizeof (struct ib_uverbs_async_event_desc);
  	else
  		eventsz = sizeof (struct ib_uverbs_comp_event_desc);
  
  	if (eventsz > count) {
  		ret   = -EINVAL;
  		event = NULL;
  	} else {
  		list_del(file->event_list.next);
  		if (event->counter) {
  			++(*event->counter);
  			list_del(&event->obj_list);
  		}
  	}
  
  	spin_unlock_irq(&file->lock);
  
  	if (event) {
  		if (copy_to_user(buf, event, eventsz))
  			ret = -EFAULT;
  		else
  			ret = eventsz;
  	}
  
  	kfree(event);
  
  	return ret;
  }
  
  static unsigned int ib_uverbs_event_poll(struct file *filp,
  					 struct poll_table_struct *wait)
  {
  	unsigned int pollflags = 0;
  	struct ib_uverbs_event_file *file = filp->private_data;
  
  	poll_wait(filp, &file->poll_wait, wait);
  
  	spin_lock_irq(&file->lock);
  	if (!list_empty(&file->event_list))
  		pollflags = POLLIN | POLLRDNORM;
  	spin_unlock_irq(&file->lock);
  
  	return pollflags;
  }
  
  static int ib_uverbs_event_fasync(int fd, struct file *filp, int on)
  {
  	struct ib_uverbs_event_file *file = filp->private_data;
  
  	return fasync_helper(fd, filp, on, &file->async_queue);
  }
  
  static int ib_uverbs_event_close(struct inode *inode, struct file *filp)
  {
  	struct ib_uverbs_event_file *file = filp->private_data;
  	struct ib_uverbs_event *entry, *tmp;
  	int closed_already = 0;
  
  	mutex_lock(&file->uverbs_file->device->lists_mutex);
  	spin_lock_irq(&file->lock);
  	closed_already = file->is_closed;
  	file->is_closed = 1;
  	list_for_each_entry_safe(entry, tmp, &file->event_list, list) {
  		if (entry->counter)
  			list_del(&entry->obj_list);
  		kfree(entry);
  	}
  	spin_unlock_irq(&file->lock);
  	if (!closed_already) {
  		list_del(&file->list);
  		if (file->is_async)
  			ib_unregister_event_handler(&file->uverbs_file->
  				event_handler);
  	}
  	mutex_unlock(&file->uverbs_file->device->lists_mutex);
  
  	kref_put(&file->uverbs_file->ref, ib_uverbs_release_file);
  	kref_put(&file->ref, ib_uverbs_release_event_file);
  
  	return 0;
  }
  
  static const struct file_operations uverbs_event_fops = {
  	.owner	 = THIS_MODULE,
  	.read	 = ib_uverbs_event_read,
  	.poll    = ib_uverbs_event_poll,
  	.release = ib_uverbs_event_close,
  	.fasync  = ib_uverbs_event_fasync,
  	.llseek	 = no_llseek,
  };
  
  void ib_uverbs_comp_handler(struct ib_cq *cq, void *cq_context)
  {
  	struct ib_uverbs_event_file    *file = cq_context;
  	struct ib_ucq_object	       *uobj;
  	struct ib_uverbs_event	       *entry;
  	unsigned long			flags;
  
  	if (!file)
  		return;
  
  	spin_lock_irqsave(&file->lock, flags);
  	if (file->is_closed) {
  		spin_unlock_irqrestore(&file->lock, flags);
  		return;
  	}
  
  	entry = kmalloc(sizeof *entry, GFP_ATOMIC);
  	if (!entry) {
  		spin_unlock_irqrestore(&file->lock, flags);
  		return;
  	}
  
  	uobj = container_of(cq->uobject, struct ib_ucq_object, uobject);
  
  	entry->desc.comp.cq_handle = cq->uobject->user_handle;
  	entry->counter		   = &uobj->comp_events_reported;
  
  	list_add_tail(&entry->list, &file->event_list);
  	list_add_tail(&entry->obj_list, &uobj->comp_list);
  	spin_unlock_irqrestore(&file->lock, flags);
  
  	wake_up_interruptible(&file->poll_wait);
  	kill_fasync(&file->async_queue, SIGIO, POLL_IN);
  }
  
  static void ib_uverbs_async_handler(struct ib_uverbs_file *file,
  				    __u64 element, __u64 event,
  				    struct list_head *obj_list,
  				    u32 *counter)
  {
  	struct ib_uverbs_event *entry;
  	unsigned long flags;
  
  	spin_lock_irqsave(&file->async_file->lock, flags);
  	if (file->async_file->is_closed) {
  		spin_unlock_irqrestore(&file->async_file->lock, flags);
  		return;
  	}
  
  	entry = kmalloc(sizeof *entry, GFP_ATOMIC);
  	if (!entry) {
  		spin_unlock_irqrestore(&file->async_file->lock, flags);
  		return;
  	}
  
  	entry->desc.async.element    = element;
  	entry->desc.async.event_type = event;
  	entry->desc.async.reserved   = 0;
  	entry->counter               = counter;
  
  	list_add_tail(&entry->list, &file->async_file->event_list);
  	if (obj_list)
  		list_add_tail(&entry->obj_list, obj_list);
  	spin_unlock_irqrestore(&file->async_file->lock, flags);
  
  	wake_up_interruptible(&file->async_file->poll_wait);
  	kill_fasync(&file->async_file->async_queue, SIGIO, POLL_IN);
  }
  
  void ib_uverbs_cq_event_handler(struct ib_event *event, void *context_ptr)
  {
  	struct ib_ucq_object *uobj = container_of(event->element.cq->uobject,
  						  struct ib_ucq_object, uobject);
  
  	ib_uverbs_async_handler(uobj->uverbs_file, uobj->uobject.user_handle,
  				event->event, &uobj->async_list,
  				&uobj->async_events_reported);
  }
  
  void ib_uverbs_qp_event_handler(struct ib_event *event, void *context_ptr)
  {
  	struct ib_uevent_object *uobj;
  
  	/* for XRC target qp's, check that qp is live */
  	if (!event->element.qp->uobject || !event->element.qp->uobject->live)
  		return;
  
  	uobj = container_of(event->element.qp->uobject,
  			    struct ib_uevent_object, uobject);
  
  	ib_uverbs_async_handler(context_ptr, uobj->uobject.user_handle,
  				event->event, &uobj->event_list,
  				&uobj->events_reported);
  }
  
  void ib_uverbs_wq_event_handler(struct ib_event *event, void *context_ptr)
  {
  	struct ib_uevent_object *uobj = container_of(event->element.wq->uobject,
  						  struct ib_uevent_object, uobject);
  
  	ib_uverbs_async_handler(context_ptr, uobj->uobject.user_handle,
  				event->event, &uobj->event_list,
  				&uobj->events_reported);
  }
  
  void ib_uverbs_srq_event_handler(struct ib_event *event, void *context_ptr)
  {
  	struct ib_uevent_object *uobj;
  
  	uobj = container_of(event->element.srq->uobject,
  			    struct ib_uevent_object, uobject);
  
  	ib_uverbs_async_handler(context_ptr, uobj->uobject.user_handle,
  				event->event, &uobj->event_list,
  				&uobj->events_reported);
  }
  
  void ib_uverbs_event_handler(struct ib_event_handler *handler,
  			     struct ib_event *event)
  {
  	struct ib_uverbs_file *file =
  		container_of(handler, struct ib_uverbs_file, event_handler);
  
  	ib_uverbs_async_handler(file, event->element.port_num, event->event,
  				NULL, NULL);
  }
  
  void ib_uverbs_free_async_event_file(struct ib_uverbs_file *file)
  {
  	kref_put(&file->async_file->ref, ib_uverbs_release_event_file);
  	file->async_file = NULL;
  }
  
  struct file *ib_uverbs_alloc_event_file(struct ib_uverbs_file *uverbs_file,
  					struct ib_device	*ib_dev,
  					int is_async)
  {
  	struct ib_uverbs_event_file *ev_file;
  	struct file *filp;
  	int ret;
  
  	ev_file = kzalloc(sizeof(*ev_file), GFP_KERNEL);
  	if (!ev_file)
  		return ERR_PTR(-ENOMEM);
  
  	kref_init(&ev_file->ref);
  	spin_lock_init(&ev_file->lock);
  	INIT_LIST_HEAD(&ev_file->event_list);
  	init_waitqueue_head(&ev_file->poll_wait);
  	ev_file->uverbs_file = uverbs_file;
  	kref_get(&ev_file->uverbs_file->ref);
  	ev_file->async_queue = NULL;
  	ev_file->is_closed   = 0;
  
  	filp = anon_inode_getfile("[infinibandevent]", &uverbs_event_fops,
  				  ev_file, O_RDONLY);
  	if (IS_ERR(filp))
  		goto err_put_refs;
  
  	mutex_lock(&uverbs_file->device->lists_mutex);
  	list_add_tail(&ev_file->list,
  		      &uverbs_file->device->uverbs_events_file_list);
  	mutex_unlock(&uverbs_file->device->lists_mutex);
  
  	if (is_async) {
  		WARN_ON(uverbs_file->async_file);
  		uverbs_file->async_file = ev_file;
  		kref_get(&uverbs_file->async_file->ref);
  		INIT_IB_EVENT_HANDLER(&uverbs_file->event_handler,
  				      ib_dev,
  				      ib_uverbs_event_handler);
  		ret = ib_register_event_handler(&uverbs_file->event_handler);
  		if (ret)
  			goto err_put_file;
  
  		/* At that point async file stuff was fully set */
  		ev_file->is_async = 1;
  	}
  
  	return filp;
  
  err_put_file:
  	fput(filp);
  	kref_put(&uverbs_file->async_file->ref, ib_uverbs_release_event_file);
  	uverbs_file->async_file = NULL;
  	return ERR_PTR(ret);
  
  err_put_refs:
  	kref_put(&ev_file->uverbs_file->ref, ib_uverbs_release_file);
  	kref_put(&ev_file->ref, ib_uverbs_release_event_file);
  	return filp;
  }
  
  /*
   * Look up a completion event file by FD.  If lookup is successful,
   * takes a ref to the event file struct that it returns; if
   * unsuccessful, returns NULL.
   */
  struct ib_uverbs_event_file *ib_uverbs_lookup_comp_file(int fd)
  {
  	struct ib_uverbs_event_file *ev_file = NULL;
  	struct fd f = fdget(fd);
  
  	if (!f.file)
  		return NULL;
  
  	if (f.file->f_op != &uverbs_event_fops)
  		goto out;
  
  	ev_file = f.file->private_data;
  	if (ev_file->is_async) {
  		ev_file = NULL;
  		goto out;
  	}
  
  	kref_get(&ev_file->ref);
  
  out:
  	fdput(f);
  	return ev_file;
  }
  
  static int verify_command_mask(struct ib_device *ib_dev, __u32 command)
  {
  	u64 mask;
  
  	if (command <= IB_USER_VERBS_CMD_OPEN_QP)
  		mask = ib_dev->uverbs_cmd_mask;
  	else
  		mask = ib_dev->uverbs_ex_cmd_mask;
  
  	if (mask & ((u64)1 << command))
  		return 0;
  
  	return -1;
  }
  
  static ssize_t ib_uverbs_write(struct file *filp, const char __user *buf,
  			     size_t count, loff_t *pos)
  {
  	struct ib_uverbs_file *file = filp->private_data;
  	struct ib_device *ib_dev;
  	struct ib_uverbs_cmd_hdr hdr;
  	__u32 command;
  	__u32 flags;
  	int srcu_key;
  	ssize_t ret;
  
  	if (!ib_safe_file_access(filp)) {
  		pr_err_once("uverbs_write: process %d (%s) changed security contexts after opening file descriptor, this is not allowed.\n",
  			    task_tgid_vnr(current), current->comm);
  		return -EACCES;
  	}
  
  	if (count < sizeof hdr)
  		return -EINVAL;
  
  	if (copy_from_user(&hdr, buf, sizeof hdr))
  		return -EFAULT;
  
  	srcu_key = srcu_read_lock(&file->device->disassociate_srcu);
  	ib_dev = srcu_dereference(file->device->ib_dev,
  				  &file->device->disassociate_srcu);
  	if (!ib_dev) {
  		ret = -EIO;
  		goto out;
  	}
  
  	if (hdr.command & ~(__u32)(IB_USER_VERBS_CMD_FLAGS_MASK |
  				   IB_USER_VERBS_CMD_COMMAND_MASK)) {
  		ret = -EINVAL;
  		goto out;
  	}
  
  	command = hdr.command & IB_USER_VERBS_CMD_COMMAND_MASK;
  	if (verify_command_mask(ib_dev, command)) {
  		ret = -EOPNOTSUPP;
  		goto out;
  	}
  
  	if (!file->ucontext &&
  	    command != IB_USER_VERBS_CMD_GET_CONTEXT) {
  		ret = -EINVAL;
  		goto out;
  	}
  
  	flags = (hdr.command &
  		 IB_USER_VERBS_CMD_FLAGS_MASK) >> IB_USER_VERBS_CMD_FLAGS_SHIFT;
  
  	if (!flags) {
  		if (command >= ARRAY_SIZE(uverbs_cmd_table) ||
  		    !uverbs_cmd_table[command]) {
  			ret = -EINVAL;
  			goto out;
  		}
  
  		if (hdr.in_words * 4 != count) {
  			ret = -EINVAL;
  			goto out;
  		}
  
  		ret = uverbs_cmd_table[command](file, ib_dev,
  						 buf + sizeof(hdr),
  						 hdr.in_words * 4,
  						 hdr.out_words * 4);
  
  	} else if (flags == IB_USER_VERBS_CMD_FLAG_EXTENDED) {
  		struct ib_uverbs_ex_cmd_hdr ex_hdr;
  		struct ib_udata ucore;
  		struct ib_udata uhw;
  		size_t written_count = count;
  
  		if (command >= ARRAY_SIZE(uverbs_ex_cmd_table) ||
  		    !uverbs_ex_cmd_table[command]) {
  			ret = -ENOSYS;
  			goto out;
  		}
  
  		if (!file->ucontext) {
  			ret = -EINVAL;
  			goto out;
  		}
  
  		if (count < (sizeof(hdr) + sizeof(ex_hdr))) {
  			ret = -EINVAL;
  			goto out;
  		}
  
  		if (copy_from_user(&ex_hdr, buf + sizeof(hdr), sizeof(ex_hdr))) {
  			ret = -EFAULT;
  			goto out;
  		}
  
  		count -= sizeof(hdr) + sizeof(ex_hdr);
  		buf += sizeof(hdr) + sizeof(ex_hdr);
  
  		if ((hdr.in_words + ex_hdr.provider_in_words) * 8 != count) {
  			ret = -EINVAL;
  			goto out;
  		}
  
  		if (ex_hdr.cmd_hdr_reserved) {
  			ret = -EINVAL;
  			goto out;
  		}
  
  		if (ex_hdr.response) {
  			if (!hdr.out_words && !ex_hdr.provider_out_words) {
  				ret = -EINVAL;
  				goto out;
  			}
  
  			if (!access_ok(VERIFY_WRITE,
  				       (void __user *) (unsigned long) ex_hdr.response,
  				       (hdr.out_words + ex_hdr.provider_out_words) * 8)) {
  				ret = -EFAULT;
  				goto out;
  			}
  		} else {
  			if (hdr.out_words || ex_hdr.provider_out_words) {
  				ret = -EINVAL;
  				goto out;
  			}
  		}
  
  		INIT_UDATA_BUF_OR_NULL(&ucore, buf, (unsigned long) ex_hdr.response,
  				       hdr.in_words * 8, hdr.out_words * 8);
  
  		INIT_UDATA_BUF_OR_NULL(&uhw,
  				       buf + ucore.inlen,
  				       (unsigned long) ex_hdr.response + ucore.outlen,
  				       ex_hdr.provider_in_words * 8,
  				       ex_hdr.provider_out_words * 8);
  
  		ret = uverbs_ex_cmd_table[command](file,
  						   ib_dev,
  						   &ucore,
  						   &uhw);
  		if (!ret)
  			ret = written_count;
  	} else {
  		ret = -ENOSYS;
  	}
  
  out:
  	srcu_read_unlock(&file->device->disassociate_srcu, srcu_key);
  	return ret;
  }
  
  static int ib_uverbs_mmap(struct file *filp, struct vm_area_struct *vma)
  {
  	struct ib_uverbs_file *file = filp->private_data;
  	struct ib_device *ib_dev;
  	int ret = 0;
  	int srcu_key;
  
  	srcu_key = srcu_read_lock(&file->device->disassociate_srcu);
  	ib_dev = srcu_dereference(file->device->ib_dev,
  				  &file->device->disassociate_srcu);
  	if (!ib_dev) {
  		ret = -EIO;
  		goto out;
  	}
  
  	if (!file->ucontext)
  		ret = -ENODEV;
  	else
  		ret = ib_dev->mmap(file->ucontext, vma);
  out:
  	srcu_read_unlock(&file->device->disassociate_srcu, srcu_key);
  	return ret;
  }
  
  /*
   * ib_uverbs_open() does not need the BKL:
   *
   *  - the ib_uverbs_device structures are properly reference counted and
   *    everything else is purely local to the file being created, so
   *    races against other open calls are not a problem;
   *  - there is no ioctl method to race against;
   *  - the open method will either immediately run -ENXIO, or all
   *    required initialization will be done.
   */
  static int ib_uverbs_open(struct inode *inode, struct file *filp)
  {
  	struct ib_uverbs_device *dev;
  	struct ib_uverbs_file *file;
  	struct ib_device *ib_dev;
  	int ret;
  	int module_dependent;
  	int srcu_key;
  
  	dev = container_of(inode->i_cdev, struct ib_uverbs_device, cdev);
  	if (!atomic_inc_not_zero(&dev->refcount))
  		return -ENXIO;
  
  	srcu_key = srcu_read_lock(&dev->disassociate_srcu);
  	mutex_lock(&dev->lists_mutex);
  	ib_dev = srcu_dereference(dev->ib_dev,
  				  &dev->disassociate_srcu);
  	if (!ib_dev) {
  		ret = -EIO;
  		goto err;
  	}
  
  	/* In case IB device supports disassociate ucontext, there is no hard
  	 * dependency between uverbs device and its low level device.
  	 */
  	module_dependent = !(ib_dev->disassociate_ucontext);
  
  	if (module_dependent) {
  		if (!try_module_get(ib_dev->owner)) {
  			ret = -ENODEV;
  			goto err;
  		}
  	}
  
  	file = kzalloc(sizeof(*file), GFP_KERNEL);
  	if (!file) {
  		ret = -ENOMEM;
  		if (module_dependent)
  			goto err_module;
  
  		goto err;
  	}
  
  	file->device	 = dev;
  	file->ucontext	 = NULL;
  	file->async_file = NULL;
  	kref_init(&file->ref);
  	mutex_init(&file->mutex);
  	mutex_init(&file->cleanup_mutex);
  
  	filp->private_data = file;
  	kobject_get(&dev->kobj);
  	list_add_tail(&file->list, &dev->uverbs_file_list);
  	mutex_unlock(&dev->lists_mutex);
  	srcu_read_unlock(&dev->disassociate_srcu, srcu_key);
  
  	return nonseekable_open(inode, filp);
  
  err_module:
  	module_put(ib_dev->owner);
  
  err:
  	mutex_unlock(&dev->lists_mutex);
  	srcu_read_unlock(&dev->disassociate_srcu, srcu_key);
  	if (atomic_dec_and_test(&dev->refcount))
  		ib_uverbs_comp_dev(dev);
  
  	return ret;
  }
  
  static int ib_uverbs_close(struct inode *inode, struct file *filp)
  {
  	struct ib_uverbs_file *file = filp->private_data;
  	struct ib_uverbs_device *dev = file->device;
  
  	mutex_lock(&file->cleanup_mutex);
  	if (file->ucontext) {
  		ib_uverbs_cleanup_ucontext(file, file->ucontext);
  		file->ucontext = NULL;
  	}
  	mutex_unlock(&file->cleanup_mutex);
  
  	mutex_lock(&file->device->lists_mutex);
  	if (!file->is_closed) {
  		list_del(&file->list);
  		file->is_closed = 1;
  	}
  	mutex_unlock(&file->device->lists_mutex);
  
  	if (file->async_file)
  		kref_put(&file->async_file->ref, ib_uverbs_release_event_file);
  
  	kref_put(&file->ref, ib_uverbs_release_file);
  	kobject_put(&dev->kobj);
  
  	return 0;
  }
  
  static const struct file_operations uverbs_fops = {
  	.owner	 = THIS_MODULE,
  	.write	 = ib_uverbs_write,
  	.open	 = ib_uverbs_open,
  	.release = ib_uverbs_close,
  	.llseek	 = no_llseek,
  };
  
  static const struct file_operations uverbs_mmap_fops = {
  	.owner	 = THIS_MODULE,
  	.write	 = ib_uverbs_write,
  	.mmap    = ib_uverbs_mmap,
  	.open	 = ib_uverbs_open,
  	.release = ib_uverbs_close,
  	.llseek	 = no_llseek,
  };
  
  static struct ib_client uverbs_client = {
  	.name   = "uverbs",
  	.add    = ib_uverbs_add_one,
  	.remove = ib_uverbs_remove_one
  };
  
  static ssize_t show_ibdev(struct device *device, struct device_attribute *attr,
  			  char *buf)
  {
  	int ret = -ENODEV;
  	int srcu_key;
  	struct ib_uverbs_device *dev = dev_get_drvdata(device);
  	struct ib_device *ib_dev;
  
  	if (!dev)
  		return -ENODEV;
  
  	srcu_key = srcu_read_lock(&dev->disassociate_srcu);
  	ib_dev = srcu_dereference(dev->ib_dev, &dev->disassociate_srcu);
  	if (ib_dev)
  		ret = sprintf(buf, "%s\n", ib_dev->name);
  	srcu_read_unlock(&dev->disassociate_srcu, srcu_key);
  
  	return ret;
  }
  static DEVICE_ATTR(ibdev, S_IRUGO, show_ibdev, NULL);
  
  static ssize_t show_dev_abi_version(struct device *device,
  				    struct device_attribute *attr, char *buf)
  {
  	struct ib_uverbs_device *dev = dev_get_drvdata(device);
  	int ret = -ENODEV;
  	int srcu_key;
  	struct ib_device *ib_dev;
  
  	if (!dev)
  		return -ENODEV;
  	srcu_key = srcu_read_lock(&dev->disassociate_srcu);
  	ib_dev = srcu_dereference(dev->ib_dev, &dev->disassociate_srcu);
  	if (ib_dev)
  		ret = sprintf(buf, "%d\n", ib_dev->uverbs_abi_ver);
  	srcu_read_unlock(&dev->disassociate_srcu, srcu_key);
  
  	return ret;
  }
  static DEVICE_ATTR(abi_version, S_IRUGO, show_dev_abi_version, NULL);
  
  static CLASS_ATTR_STRING(abi_version, S_IRUGO,
  			 __stringify(IB_USER_VERBS_ABI_VERSION));
  
  static dev_t overflow_maj;
  static DECLARE_BITMAP(overflow_map, IB_UVERBS_MAX_DEVICES);
  
  /*
   * If we have more than IB_UVERBS_MAX_DEVICES, dynamically overflow by
   * requesting a new major number and doubling the number of max devices we
   * support. It's stupid, but simple.
   */
  static int find_overflow_devnum(void)
  {
  	int ret;
  
  	if (!overflow_maj) {
  		ret = alloc_chrdev_region(&overflow_maj, 0, IB_UVERBS_MAX_DEVICES,
  					  "infiniband_verbs");
  		if (ret) {
  			pr_err("user_verbs: couldn't register dynamic device number\n");
  			return ret;
  		}
  	}
  
  	ret = find_first_zero_bit(overflow_map, IB_UVERBS_MAX_DEVICES);
  	if (ret >= IB_UVERBS_MAX_DEVICES)
  		return -1;
  
  	return ret;
  }
  
  static void ib_uverbs_add_one(struct ib_device *device)
  {
  	int devnum;
  	dev_t base;
  	struct ib_uverbs_device *uverbs_dev;
  	int ret;
  
  	if (!device->alloc_ucontext)
  		return;
  
  	uverbs_dev = kzalloc(sizeof *uverbs_dev, GFP_KERNEL);
  	if (!uverbs_dev)
  		return;
  
  	ret = init_srcu_struct(&uverbs_dev->disassociate_srcu);
  	if (ret) {
  		kfree(uverbs_dev);
  		return;
  	}
  
  	atomic_set(&uverbs_dev->refcount, 1);
  	init_completion(&uverbs_dev->comp);
  	uverbs_dev->xrcd_tree = RB_ROOT;
  	mutex_init(&uverbs_dev->xrcd_tree_mutex);
  	kobject_init(&uverbs_dev->kobj, &ib_uverbs_dev_ktype);
  	mutex_init(&uverbs_dev->lists_mutex);
  	INIT_LIST_HEAD(&uverbs_dev->uverbs_file_list);
  	INIT_LIST_HEAD(&uverbs_dev->uverbs_events_file_list);
  
  	spin_lock(&map_lock);
  	devnum = find_first_zero_bit(dev_map, IB_UVERBS_MAX_DEVICES);
  	if (devnum >= IB_UVERBS_MAX_DEVICES) {
  		spin_unlock(&map_lock);
  		devnum = find_overflow_devnum();
  		if (devnum < 0)
  			goto err;
  
  		spin_lock(&map_lock);
  		uverbs_dev->devnum = devnum + IB_UVERBS_MAX_DEVICES;
  		base = devnum + overflow_maj;
  		set_bit(devnum, overflow_map);
  	} else {
  		uverbs_dev->devnum = devnum;
  		base = devnum + IB_UVERBS_BASE_DEV;
  		set_bit(devnum, dev_map);
  	}
  	spin_unlock(&map_lock);
  
  	rcu_assign_pointer(uverbs_dev->ib_dev, device);
  	uverbs_dev->num_comp_vectors = device->num_comp_vectors;
  
  	cdev_init(&uverbs_dev->cdev, NULL);
  	uverbs_dev->cdev.owner = THIS_MODULE;
  	uverbs_dev->cdev.ops = device->mmap ? &uverbs_mmap_fops : &uverbs_fops;
  	uverbs_dev->cdev.kobj.parent = &uverbs_dev->kobj;
  	kobject_set_name(&uverbs_dev->cdev.kobj, "uverbs%d", uverbs_dev->devnum);
  	if (cdev_add(&uverbs_dev->cdev, base, 1))
  		goto err_cdev;
  
  	uverbs_dev->dev = device_create(uverbs_class, device->dev.parent,
  					uverbs_dev->cdev.dev, uverbs_dev,
  					"uverbs%d", uverbs_dev->devnum);
  	if (IS_ERR(uverbs_dev->dev))
  		goto err_cdev;
  
  	if (device_create_file(uverbs_dev->dev, &dev_attr_ibdev))
  		goto err_class;
  	if (device_create_file(uverbs_dev->dev, &dev_attr_abi_version))
  		goto err_class;
  
  	ib_set_client_data(device, &uverbs_client, uverbs_dev);
  
  	return;
  
  err_class:
  	device_destroy(uverbs_class, uverbs_dev->cdev.dev);
  
  err_cdev:
  	cdev_del(&uverbs_dev->cdev);
  	if (uverbs_dev->devnum < IB_UVERBS_MAX_DEVICES)
  		clear_bit(devnum, dev_map);
  	else
  		clear_bit(devnum, overflow_map);
  
  err:
  	if (atomic_dec_and_test(&uverbs_dev->refcount))
  		ib_uverbs_comp_dev(uverbs_dev);
  	wait_for_completion(&uverbs_dev->comp);
  	kobject_put(&uverbs_dev->kobj);
  	return;
  }
  
  static void ib_uverbs_free_hw_resources(struct ib_uverbs_device *uverbs_dev,
  					struct ib_device *ib_dev)
  {
  	struct ib_uverbs_file *file;
  	struct ib_uverbs_event_file *event_file;
  	struct ib_event event;
  
  	/* Pending running commands to terminate */
  	synchronize_srcu(&uverbs_dev->disassociate_srcu);
  	event.event = IB_EVENT_DEVICE_FATAL;
  	event.element.port_num = 0;
  	event.device = ib_dev;
  
  	mutex_lock(&uverbs_dev->lists_mutex);
  	while (!list_empty(&uverbs_dev->uverbs_file_list)) {
  		struct ib_ucontext *ucontext;
  		file = list_first_entry(&uverbs_dev->uverbs_file_list,
  					struct ib_uverbs_file, list);
  		file->is_closed = 1;
  		list_del(&file->list);
  		kref_get(&file->ref);
  		mutex_unlock(&uverbs_dev->lists_mutex);
  
  		ib_uverbs_event_handler(&file->event_handler, &event);
  
  		mutex_lock(&file->cleanup_mutex);
  		ucontext = file->ucontext;
  		file->ucontext = NULL;
  		mutex_unlock(&file->cleanup_mutex);
  
  		/* At this point ib_uverbs_close cannot be running
  		 * ib_uverbs_cleanup_ucontext
  		 */
  		if (ucontext) {
  			/* We must release the mutex before going ahead and
  			 * calling disassociate_ucontext. disassociate_ucontext
  			 * might end up indirectly calling uverbs_close,
  			 * for example due to freeing the resources
  			 * (e.g mmput).
  			 */
  			ib_dev->disassociate_ucontext(ucontext);
  			ib_uverbs_cleanup_ucontext(file, ucontext);
  		}
  
  		mutex_lock(&uverbs_dev->lists_mutex);
  		kref_put(&file->ref, ib_uverbs_release_file);
  	}
  
  	while (!list_empty(&uverbs_dev->uverbs_events_file_list)) {
  		event_file = list_first_entry(&uverbs_dev->
  					      uverbs_events_file_list,
  					      struct ib_uverbs_event_file,
  					      list);
  		spin_lock_irq(&event_file->lock);
  		event_file->is_closed = 1;
  		spin_unlock_irq(&event_file->lock);
  
  		list_del(&event_file->list);
  		if (event_file->is_async) {
  			ib_unregister_event_handler(&event_file->uverbs_file->
  						    event_handler);
  			event_file->uverbs_file->event_handler.device = NULL;
  		}
  
  		wake_up_interruptible(&event_file->poll_wait);
  		kill_fasync(&event_file->async_queue, SIGIO, POLL_IN);
  	}
  	mutex_unlock(&uverbs_dev->lists_mutex);
  }
  
  static void ib_uverbs_remove_one(struct ib_device *device, void *client_data)
  {
  	struct ib_uverbs_device *uverbs_dev = client_data;
  	int wait_clients = 1;
  
  	if (!uverbs_dev)
  		return;
  
  	dev_set_drvdata(uverbs_dev->dev, NULL);
  	device_destroy(uverbs_class, uverbs_dev->cdev.dev);
  	cdev_del(&uverbs_dev->cdev);
  
  	if (uverbs_dev->devnum < IB_UVERBS_MAX_DEVICES)
  		clear_bit(uverbs_dev->devnum, dev_map);
  	else
  		clear_bit(uverbs_dev->devnum - IB_UVERBS_MAX_DEVICES, overflow_map);
  
  	if (device->disassociate_ucontext) {
  		/* We disassociate HW resources and immediately return.
  		 * Userspace will see a EIO errno for all future access.
  		 * Upon returning, ib_device may be freed internally and is not
  		 * valid any more.
  		 * uverbs_device is still available until all clients close
  		 * their files, then the uverbs device ref count will be zero
  		 * and its resources will be freed.
  		 * Note: At this point no more files can be opened since the
  		 * cdev was deleted, however active clients can still issue
  		 * commands and close their open files.
  		 */
  		rcu_assign_pointer(uverbs_dev->ib_dev, NULL);
  		ib_uverbs_free_hw_resources(uverbs_dev, device);
  		wait_clients = 0;
  	}
  
  	if (atomic_dec_and_test(&uverbs_dev->refcount))
  		ib_uverbs_comp_dev(uverbs_dev);
  	if (wait_clients)
  		wait_for_completion(&uverbs_dev->comp);
  	kobject_put(&uverbs_dev->kobj);
  }
  
  static char *uverbs_devnode(struct device *dev, umode_t *mode)
  {
  	if (mode)
  		*mode = 0666;
  	return kasprintf(GFP_KERNEL, "infiniband/%s", dev_name(dev));
  }
  
  static int __init ib_uverbs_init(void)
  {
  	int ret;
  
  	ret = register_chrdev_region(IB_UVERBS_BASE_DEV, IB_UVERBS_MAX_DEVICES,
  				     "infiniband_verbs");
  	if (ret) {
  		pr_err("user_verbs: couldn't register device number\n");
  		goto out;
  	}
  
  	uverbs_class = class_create(THIS_MODULE, "infiniband_verbs");
  	if (IS_ERR(uverbs_class)) {
  		ret = PTR_ERR(uverbs_class);
  		pr_err("user_verbs: couldn't create class infiniband_verbs\n");
  		goto out_chrdev;
  	}
  
  	uverbs_class->devnode = uverbs_devnode;
  
  	ret = class_create_file(uverbs_class, &class_attr_abi_version.attr);
  	if (ret) {
  		pr_err("user_verbs: couldn't create abi_version attribute\n");
  		goto out_class;
  	}
  
  	ret = ib_register_client(&uverbs_client);
  	if (ret) {
  		pr_err("user_verbs: couldn't register client\n");
  		goto out_class;
  	}
  
  	return 0;
  
  out_class:
  	class_destroy(uverbs_class);
  
  out_chrdev:
  	unregister_chrdev_region(IB_UVERBS_BASE_DEV, IB_UVERBS_MAX_DEVICES);
  
  out:
  	return ret;
  }
  
  static void __exit ib_uverbs_cleanup(void)
  {
  	ib_unregister_client(&uverbs_client);
  	class_destroy(uverbs_class);
  	unregister_chrdev_region(IB_UVERBS_BASE_DEV, IB_UVERBS_MAX_DEVICES);
  	if (overflow_maj)
  		unregister_chrdev_region(overflow_maj, IB_UVERBS_MAX_DEVICES);
  	idr_destroy(&ib_uverbs_pd_idr);
  	idr_destroy(&ib_uverbs_mr_idr);
  	idr_destroy(&ib_uverbs_mw_idr);
  	idr_destroy(&ib_uverbs_ah_idr);
  	idr_destroy(&ib_uverbs_cq_idr);
  	idr_destroy(&ib_uverbs_qp_idr);
  	idr_destroy(&ib_uverbs_srq_idr);
  }
  
  module_init(ib_uverbs_init);
  module_exit(ib_uverbs_cleanup);
  