OSCL-LXR linux-6.0.1/​drivers/​infiniband/​core/​uverbs_main.c	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 /*
  * 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/sched/mm.h>
 
 #include <linux/uaccess.h>
 
 #include <rdma/ib.h>
 #include <rdma/uverbs_std_types.h>
 #include <rdma/rdma_netlink.h>
 
 #include "uverbs.h"
 #include "core_priv.h"
 #include "rdma_core.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 = RDMA_MAX_PORTS,
     IB_UVERBS_NUM_FIXED_MINOR = 32,
     IB_UVERBS_NUM_DYNAMIC_MINOR = IB_UVERBS_MAX_DEVICES - IB_UVERBS_NUM_FIXED_MINOR,
 };
 
 #define IB_UVERBS_BASE_DEV  MKDEV(IB_UVERBS_MAJOR, IB_UVERBS_BASE_MINOR)
 
 static dev_t dynamic_uverbs_dev;
 static struct class *uverbs_class;
 
 static DEFINE_IDA(uverbs_ida);
 static int ib_uverbs_add_one(struct ib_device *device);
 static void ib_uverbs_remove_one(struct ib_device *device, void *client_data);
 
 /*
  * Must be called with the ufile->device->disassociate_srcu held, and the lock
  * must be held until use of the ucontext is finished.
  */
 struct ib_ucontext *ib_uverbs_get_ucontext_file(struct ib_uverbs_file *ufile)
 {
     /*
      * We do not hold the hw_destroy_rwsem lock for this flow, instead
      * srcu is used. It does not matter if someone races this with
      * get_context, we get NULL or valid ucontext.
      */
     struct ib_ucontext *ucontext = smp_load_acquire(&ufile->ucontext);
 
     if (!srcu_dereference(ufile->device->ib_dev,
                   &ufile->device->disassociate_srcu))
         return ERR_PTR(-EIO);
 
     if (!ucontext)
         return ERR_PTR(-EINVAL);
 
     return ucontext;
 }
 EXPORT_SYMBOL(ib_uverbs_get_ucontext_file);
 
 int uverbs_dealloc_mw(struct ib_mw *mw)
 {
     struct ib_pd *pd = mw->pd;
     int ret;
 
     ret = mw->device->ops.dealloc_mw(mw);
     if (ret)
         return ret;
 
     atomic_dec(&pd->usecnt);
     kfree(mw);
     return ret;
 }
 
 static void ib_uverbs_release_dev(struct device *device)
 {
     struct ib_uverbs_device *dev =
             container_of(device, struct ib_uverbs_device, dev);
 
     uverbs_destroy_api(dev->uapi);
     cleanup_srcu_struct(&dev->disassociate_srcu);
     mutex_destroy(&dev->lists_mutex);
     mutex_destroy(&dev->xrcd_tree_mutex);
     kfree(dev);
 }
 
 void ib_uverbs_release_ucq(struct ib_uverbs_completion_event_file *ev_file,
                struct ib_ucq_object *uobj)
 {
     struct ib_uverbs_event *evt, *tmp;
 
     if (ev_file) {
         spin_lock_irq(&ev_file->ev_queue.lock);
         list_for_each_entry_safe(evt, tmp, &uobj->comp_list, obj_list) {
             list_del(&evt->list);
             kfree(evt);
         }
         spin_unlock_irq(&ev_file->ev_queue.lock);
 
         uverbs_uobject_put(&ev_file->uobj);
     }
 
     ib_uverbs_release_uevent(&uobj->uevent);
 }
 
 void ib_uverbs_release_uevent(struct ib_uevent_object *uobj)
 {
     struct ib_uverbs_async_event_file *async_file = uobj->event_file;
     struct ib_uverbs_event *evt, *tmp;
 
     if (!async_file)
         return;
 
     spin_lock_irq(&async_file->ev_queue.lock);
     list_for_each_entry_safe(evt, tmp, &uobj->event_list, obj_list) {
         list_del(&evt->list);
         kfree(evt);
     }
     spin_unlock_irq(&async_file->ev_queue.lock);
     uverbs_uobject_put(&async_file->uobj);
 }
 
 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 void ib_uverbs_comp_dev(struct ib_uverbs_device *dev)
 {
     complete(&dev->comp);
 }
 
 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;
 
     release_ufile_idr_uobject(file);
 
     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->ops.disassociate_ucontext)
         module_put(ib_dev->ops.owner);
     srcu_read_unlock(&file->device->disassociate_srcu, srcu_key);
 
     if (refcount_dec_and_test(&file->device->refcount))
         ib_uverbs_comp_dev(file->device);
 
     if (file->default_async_file)
         uverbs_uobject_put(&file->default_async_file->uobj);
     put_device(&file->device->dev);
 
     if (file->disassociate_page)
         __free_pages(file->disassociate_page, 0);
     mutex_destroy(&file->umap_lock);
     mutex_destroy(&file->ucontext_lock);
     kfree(file);
 }
 
 static ssize_t ib_uverbs_event_read(struct ib_uverbs_event_queue *ev_queue,
                     struct file *filp, char __user *buf,
                     size_t count, loff_t *pos,
                     size_t eventsz)
 {
     struct ib_uverbs_event *event;
     int ret = 0;
 
     spin_lock_irq(&ev_queue->lock);
 
     while (list_empty(&ev_queue->event_list)) {
         spin_unlock_irq(&ev_queue->lock);
 
         if (filp->f_flags & O_NONBLOCK)
             return -EAGAIN;
 
         if (wait_event_interruptible(ev_queue->poll_wait,
                          (!list_empty(&ev_queue->event_list) ||
                           ev_queue->is_closed)))
             return -ERESTARTSYS;
 
         spin_lock_irq(&ev_queue->lock);
 
         /* If device was disassociated and no event exists set an error */
         if (list_empty(&ev_queue->event_list) && ev_queue->is_closed) {
             spin_unlock_irq(&ev_queue->lock);
             return -EIO;
         }
     }
 
     event = list_entry(ev_queue->event_list.next, struct ib_uverbs_event, list);
 
     if (eventsz > count) {
         ret   = -EINVAL;
         event = NULL;
     } else {
         list_del(ev_queue->event_list.next);
         if (event->counter) {
             ++(*event->counter);
             list_del(&event->obj_list);
         }
     }
 
     spin_unlock_irq(&ev_queue->lock);
 
     if (event) {
         if (copy_to_user(buf, event, eventsz))
             ret = -EFAULT;
         else
             ret = eventsz;
     }
 
     kfree(event);
 
     return ret;
 }
 
 static ssize_t ib_uverbs_async_event_read(struct file *filp, char __user *buf,
                       size_t count, loff_t *pos)
 {
     struct ib_uverbs_async_event_file *file = filp->private_data;
 
     return ib_uverbs_event_read(&file->ev_queue, filp, buf, count, pos,
                     sizeof(struct ib_uverbs_async_event_desc));
 }
 
 static ssize_t ib_uverbs_comp_event_read(struct file *filp, char __user *buf,
                      size_t count, loff_t *pos)
 {
     struct ib_uverbs_completion_event_file *comp_ev_file =
         filp->private_data;
 
     return ib_uverbs_event_read(&comp_ev_file->ev_queue, filp, buf, count,
                     pos,
                     sizeof(struct ib_uverbs_comp_event_desc));
 }
 
 static __poll_t ib_uverbs_event_poll(struct ib_uverbs_event_queue *ev_queue,
                      struct file *filp,
                      struct poll_table_struct *wait)
 {
     __poll_t pollflags = 0;
 
     poll_wait(filp, &ev_queue->poll_wait, wait);
 
     spin_lock_irq(&ev_queue->lock);
     if (!list_empty(&ev_queue->event_list))
         pollflags = EPOLLIN | EPOLLRDNORM;
     else if (ev_queue->is_closed)
         pollflags = EPOLLERR;
     spin_unlock_irq(&ev_queue->lock);
 
     return pollflags;
 }
 
 static __poll_t ib_uverbs_async_event_poll(struct file *filp,
                            struct poll_table_struct *wait)
 {
     struct ib_uverbs_async_event_file *file = filp->private_data;
 
     return ib_uverbs_event_poll(&file->ev_queue, filp, wait);
 }
 
 static __poll_t ib_uverbs_comp_event_poll(struct file *filp,
                           struct poll_table_struct *wait)
 {
     struct ib_uverbs_completion_event_file *comp_ev_file =
         filp->private_data;
 
     return ib_uverbs_event_poll(&comp_ev_file->ev_queue, filp, wait);
 }
 
 static int ib_uverbs_async_event_fasync(int fd, struct file *filp, int on)
 {
     struct ib_uverbs_async_event_file *file = filp->private_data;
 
     return fasync_helper(fd, filp, on, &file->ev_queue.async_queue);
 }
 
 static int ib_uverbs_comp_event_fasync(int fd, struct file *filp, int on)
 {
     struct ib_uverbs_completion_event_file *comp_ev_file =
         filp->private_data;
 
     return fasync_helper(fd, filp, on, &comp_ev_file->ev_queue.async_queue);
 }
 
 const struct file_operations uverbs_event_fops = {
     .owner   = THIS_MODULE,
     .read    = ib_uverbs_comp_event_read,
     .poll    = ib_uverbs_comp_event_poll,
     .release = uverbs_uobject_fd_release,
     .fasync  = ib_uverbs_comp_event_fasync,
     .llseek  = no_llseek,
 };
 
 const struct file_operations uverbs_async_event_fops = {
     .owner   = THIS_MODULE,
     .read    = ib_uverbs_async_event_read,
     .poll    = ib_uverbs_async_event_poll,
     .release = uverbs_async_event_release,
     .fasync  = ib_uverbs_async_event_fasync,
     .llseek  = no_llseek,
 };
 
 void ib_uverbs_comp_handler(struct ib_cq *cq, void *cq_context)
 {
     struct ib_uverbs_event_queue   *ev_queue = cq_context;
     struct ib_ucq_object           *uobj;
     struct ib_uverbs_event         *entry;
     unsigned long           flags;
 
     if (!ev_queue)
         return;
 
     spin_lock_irqsave(&ev_queue->lock, flags);
     if (ev_queue->is_closed) {
         spin_unlock_irqrestore(&ev_queue->lock, flags);
         return;
     }
 
     entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
     if (!entry) {
         spin_unlock_irqrestore(&ev_queue->lock, flags);
         return;
     }
 
     uobj = cq->uobject;
 
     entry->desc.comp.cq_handle = cq->uobject->uevent.uobject.user_handle;
     entry->counter         = &uobj->comp_events_reported;
 
     list_add_tail(&entry->list, &ev_queue->event_list);
     list_add_tail(&entry->obj_list, &uobj->comp_list);
     spin_unlock_irqrestore(&ev_queue->lock, flags);
 
     wake_up_interruptible(&ev_queue->poll_wait);
     kill_fasync(&ev_queue->async_queue, SIGIO, POLL_IN);
 }
 
 void ib_uverbs_async_handler(struct ib_uverbs_async_event_file *async_file,
                  __u64 element, __u64 event,
                  struct list_head *obj_list, u32 *counter)
 {
     struct ib_uverbs_event *entry;
     unsigned long flags;
 
     if (!async_file)
         return;
 
     spin_lock_irqsave(&async_file->ev_queue.lock, flags);
     if (async_file->ev_queue.is_closed) {
         spin_unlock_irqrestore(&async_file->ev_queue.lock, flags);
         return;
     }
 
     entry = kmalloc(sizeof(*entry), GFP_ATOMIC);
     if (!entry) {
         spin_unlock_irqrestore(&async_file->ev_queue.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, &async_file->ev_queue.event_list);
     if (obj_list)
         list_add_tail(&entry->obj_list, obj_list);
     spin_unlock_irqrestore(&async_file->ev_queue.lock, flags);
 
     wake_up_interruptible(&async_file->ev_queue.poll_wait);
     kill_fasync(&async_file->ev_queue.async_queue, SIGIO, POLL_IN);
 }
 
 static void uverbs_uobj_event(struct ib_uevent_object *eobj,
                   struct ib_event *event)
 {
     ib_uverbs_async_handler(eobj->event_file,
                 eobj->uobject.user_handle, event->event,
                 &eobj->event_list, &eobj->events_reported);
 }
 
 void ib_uverbs_cq_event_handler(struct ib_event *event, void *context_ptr)
 {
     uverbs_uobj_event(&event->element.cq->uobject->uevent, event);
 }
 
 void ib_uverbs_qp_event_handler(struct ib_event *event, void *context_ptr)
 {
     /* for XRC target qp's, check that qp is live */
     if (!event->element.qp->uobject)
         return;
 
     uverbs_uobj_event(&event->element.qp->uobject->uevent, event);
 }
 
 void ib_uverbs_wq_event_handler(struct ib_event *event, void *context_ptr)
 {
     uverbs_uobj_event(&event->element.wq->uobject->uevent, event);
 }
 
 void ib_uverbs_srq_event_handler(struct ib_event *event, void *context_ptr)
 {
     uverbs_uobj_event(&event->element.srq->uobject->uevent, event);
 }
 
 static void ib_uverbs_event_handler(struct ib_event_handler *handler,
                     struct ib_event *event)
 {
     ib_uverbs_async_handler(
         container_of(handler, struct ib_uverbs_async_event_file,
                  event_handler),
         event->element.port_num, event->event, NULL, NULL);
 }
 
 void ib_uverbs_init_event_queue(struct ib_uverbs_event_queue *ev_queue)
 {
     spin_lock_init(&ev_queue->lock);
     INIT_LIST_HEAD(&ev_queue->event_list);
     init_waitqueue_head(&ev_queue->poll_wait);
     ev_queue->is_closed   = 0;
     ev_queue->async_queue = NULL;
 }
 
 void ib_uverbs_init_async_event_file(
     struct ib_uverbs_async_event_file *async_file)
 {
     struct ib_uverbs_file *uverbs_file = async_file->uobj.ufile;
     struct ib_device *ib_dev = async_file->uobj.context->device;
 
     ib_uverbs_init_event_queue(&async_file->ev_queue);
 
     /* The first async_event_file becomes the default one for the file. */
     mutex_lock(&uverbs_file->ucontext_lock);
     if (!uverbs_file->default_async_file) {
         /* Pairs with the put in ib_uverbs_release_file */
         uverbs_uobject_get(&async_file->uobj);
         smp_store_release(&uverbs_file->default_async_file, async_file);
     }
     mutex_unlock(&uverbs_file->ucontext_lock);
 
     INIT_IB_EVENT_HANDLER(&async_file->event_handler, ib_dev,
                   ib_uverbs_event_handler);
     ib_register_event_handler(&async_file->event_handler);
 }
 
 static ssize_t verify_hdr(struct ib_uverbs_cmd_hdr *hdr,
               struct ib_uverbs_ex_cmd_hdr *ex_hdr, size_t count,
               const struct uverbs_api_write_method *method_elm)
 {
     if (method_elm->is_ex) {
         count -= sizeof(*hdr) + sizeof(*ex_hdr);
 
         if ((hdr->in_words + ex_hdr->provider_in_words) * 8 != count)
             return -EINVAL;
 
         if (hdr->in_words * 8 < method_elm->req_size)
             return -ENOSPC;
 
         if (ex_hdr->cmd_hdr_reserved)
             return -EINVAL;
 
         if (ex_hdr->response) {
             if (!hdr->out_words && !ex_hdr->provider_out_words)
                 return -EINVAL;
 
             if (hdr->out_words * 8 < method_elm->resp_size)
                 return -ENOSPC;
 
             if (!access_ok(u64_to_user_ptr(ex_hdr->response),
                        (hdr->out_words + ex_hdr->provider_out_words) * 8))
                 return -EFAULT;
         } else {
             if (hdr->out_words || ex_hdr->provider_out_words)
                 return -EINVAL;
         }
 
         return 0;
     }
 
     /* not extended command */
     if (hdr->in_words * 4 != count)
         return -EINVAL;
 
     if (count < method_elm->req_size + sizeof(hdr)) {
         /*
          * rdma-core v18 and v19 have a bug where they send DESTROY_CQ
          * with a 16 byte write instead of 24. Old kernels didn't
          * check the size so they allowed this. Now that the size is
          * checked provide a compatibility work around to not break
          * those userspaces.
          */
         if (hdr->command == IB_USER_VERBS_CMD_DESTROY_CQ &&
             count == 16) {
             hdr->in_words = 6;
             return 0;
         }
         return -ENOSPC;
     }
     if (hdr->out_words * 4 < method_elm->resp_size)
         return -ENOSPC;
 
     return 0;
 }
 
 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;
     const struct uverbs_api_write_method *method_elm;
     struct uverbs_api *uapi = file->device->uapi;
     struct ib_uverbs_ex_cmd_hdr ex_hdr;
     struct ib_uverbs_cmd_hdr hdr;
     struct uverbs_attr_bundle bundle;
     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;
 
     method_elm = uapi_get_method(uapi, hdr.command);
     if (IS_ERR(method_elm))
         return PTR_ERR(method_elm);
 
     if (method_elm->is_ex) {
         if (count < (sizeof(hdr) + sizeof(ex_hdr)))
             return -EINVAL;
         if (copy_from_user(&ex_hdr, buf + sizeof(hdr), sizeof(ex_hdr)))
             return -EFAULT;
     }
 
     ret = verify_hdr(&hdr, &ex_hdr, count, method_elm);
     if (ret)
         return ret;
 
     srcu_key = srcu_read_lock(&file->device->disassociate_srcu);
 
     buf += sizeof(hdr);
 
     memset(bundle.attr_present, 0, sizeof(bundle.attr_present));
     bundle.ufile = file;
     bundle.context = NULL; /* only valid if bundle has uobject */
     bundle.uobject = NULL;
     if (!method_elm->is_ex) {
         size_t in_len = hdr.in_words * 4 - sizeof(hdr);
         size_t out_len = hdr.out_words * 4;
         u64 response = 0;
 
         if (method_elm->has_udata) {
             bundle.driver_udata.inlen =
                 in_len - method_elm->req_size;
             in_len = method_elm->req_size;
             if (bundle.driver_udata.inlen)
                 bundle.driver_udata.inbuf = buf + in_len;
             else
                 bundle.driver_udata.inbuf = NULL;
         } else {
             memset(&bundle.driver_udata, 0,
                    sizeof(bundle.driver_udata));
         }
 
         if (method_elm->has_resp) {
             /*
              * The macros check that if has_resp is set
              * then the command request structure starts
              * with a '__aligned u64 response' member.
              */
             ret = get_user(response, (const u64 __user *)buf);
             if (ret)
                 goto out_unlock;
 
             if (method_elm->has_udata) {
                 bundle.driver_udata.outlen =
                     out_len - method_elm->resp_size;
                 out_len = method_elm->resp_size;
                 if (bundle.driver_udata.outlen)
                     bundle.driver_udata.outbuf =
                         u64_to_user_ptr(response +
                                 out_len);
                 else
                     bundle.driver_udata.outbuf = NULL;
             }
         } else {
             bundle.driver_udata.outlen = 0;
             bundle.driver_udata.outbuf = NULL;
         }
 
         ib_uverbs_init_udata_buf_or_null(
             &bundle.ucore, buf, u64_to_user_ptr(response),
             in_len, out_len);
     } else {
         buf += sizeof(ex_hdr);
 
         ib_uverbs_init_udata_buf_or_null(&bundle.ucore, buf,
                     u64_to_user_ptr(ex_hdr.response),
                     hdr.in_words * 8, hdr.out_words * 8);
 
         ib_uverbs_init_udata_buf_or_null(
             &bundle.driver_udata, buf + bundle.ucore.inlen,
             u64_to_user_ptr(ex_hdr.response) + bundle.ucore.outlen,
             ex_hdr.provider_in_words * 8,
             ex_hdr.provider_out_words * 8);
 
     }
 
     ret = method_elm->handler(&bundle);
     if (bundle.uobject)
         uverbs_finalize_object(bundle.uobject, UVERBS_ACCESS_NEW, true,
                        !ret, &bundle);
 out_unlock:
     srcu_read_unlock(&file->device->disassociate_srcu, srcu_key);
     return (ret) ? : count;
 }
 
 static const struct vm_operations_struct rdma_umap_ops;
 
 static int ib_uverbs_mmap(struct file *filp, struct vm_area_struct *vma)
 {
     struct ib_uverbs_file *file = filp->private_data;
     struct ib_ucontext *ucontext;
     int ret = 0;
     int srcu_key;
 
     srcu_key = srcu_read_lock(&file->device->disassociate_srcu);
     ucontext = ib_uverbs_get_ucontext_file(file);
     if (IS_ERR(ucontext)) {
         ret = PTR_ERR(ucontext);
         goto out;
     }
     vma->vm_ops = &rdma_umap_ops;
     ret = ucontext->device->ops.mmap(ucontext, vma);
 out:
     srcu_read_unlock(&file->device->disassociate_srcu, srcu_key);
     return ret;
 }
 
 /*
  * The VMA has been dup'd, initialize the vm_private_data with a new tracking
  * struct
  */
 static void rdma_umap_open(struct vm_area_struct *vma)
 {
     struct ib_uverbs_file *ufile = vma->vm_file->private_data;
     struct rdma_umap_priv *opriv = vma->vm_private_data;
     struct rdma_umap_priv *priv;
 
     if (!opriv)
         return;
 
     /* We are racing with disassociation */
     if (!down_read_trylock(&ufile->hw_destroy_rwsem))
         goto out_zap;
     /*
      * Disassociation already completed, the VMA should already be zapped.
      */
     if (!ufile->ucontext)
         goto out_unlock;
 
     priv = kzalloc(sizeof(*priv), GFP_KERNEL);
     if (!priv)
         goto out_unlock;
     rdma_umap_priv_init(priv, vma, opriv->entry);
 
     up_read(&ufile->hw_destroy_rwsem);
     return;
 
 out_unlock:
     up_read(&ufile->hw_destroy_rwsem);
 out_zap:
     /*
      * We can't allow the VMA to be created with the actual IO pages, that
      * would break our API contract, and it can't be stopped at this
      * point, so zap it.
      */
     vma->vm_private_data = NULL;
     zap_vma_ptes(vma, vma->vm_start, vma->vm_end - vma->vm_start);
 }
 
 static void rdma_umap_close(struct vm_area_struct *vma)
 {
     struct ib_uverbs_file *ufile = vma->vm_file->private_data;
     struct rdma_umap_priv *priv = vma->vm_private_data;
 
     if (!priv)
         return;
 
     /*
      * The vma holds a reference on the struct file that created it, which
      * in turn means that the ib_uverbs_file is guaranteed to exist at
      * this point.
      */
     mutex_lock(&ufile->umap_lock);
     if (priv->entry)
         rdma_user_mmap_entry_put(priv->entry);
 
     list_del(&priv->list);
     mutex_unlock(&ufile->umap_lock);
     kfree(priv);
 }
 
 /*
  * Once the zap_vma_ptes has been called touches to the VMA will come here and
  * we return a dummy writable zero page for all the pfns.
  */
 static vm_fault_t rdma_umap_fault(struct vm_fault *vmf)
 {
     struct ib_uverbs_file *ufile = vmf->vma->vm_file->private_data;
     struct rdma_umap_priv *priv = vmf->vma->vm_private_data;
     vm_fault_t ret = 0;
 
     if (!priv)
         return VM_FAULT_SIGBUS;
 
     /* Read only pages can just use the system zero page. */
     if (!(vmf->vma->vm_flags & (VM_WRITE | VM_MAYWRITE))) {
         vmf->page = ZERO_PAGE(vmf->address);
         get_page(vmf->page);
         return 0;
     }
 
     mutex_lock(&ufile->umap_lock);
     if (!ufile->disassociate_page)
         ufile->disassociate_page =
             alloc_pages(vmf->gfp_mask | __GFP_ZERO, 0);
 
     if (ufile->disassociate_page) {
         /*
          * This VMA is forced to always be shared so this doesn't have
          * to worry about COW.
          */
         vmf->page = ufile->disassociate_page;
         get_page(vmf->page);
     } else {
         ret = VM_FAULT_SIGBUS;
     }
     mutex_unlock(&ufile->umap_lock);
 
     return ret;
 }
 
 static const struct vm_operations_struct rdma_umap_ops = {
     .open = rdma_umap_open,
     .close = rdma_umap_close,
     .fault = rdma_umap_fault,
 };
 
 void uverbs_user_mmap_disassociate(struct ib_uverbs_file *ufile)
 {
     struct rdma_umap_priv *priv, *next_priv;
 
     lockdep_assert_held(&ufile->hw_destroy_rwsem);
 
     while (1) {
         struct mm_struct *mm = NULL;
 
         /* Get an arbitrary mm pointer that hasn't been cleaned yet */
         mutex_lock(&ufile->umap_lock);
         while (!list_empty(&ufile->umaps)) {
             int ret;
 
             priv = list_first_entry(&ufile->umaps,
                         struct rdma_umap_priv, list);
             mm = priv->vma->vm_mm;
             ret = mmget_not_zero(mm);
             if (!ret) {
                 list_del_init(&priv->list);
                 if (priv->entry) {
                     rdma_user_mmap_entry_put(priv->entry);
                     priv->entry = NULL;
                 }
                 mm = NULL;
                 continue;
             }
             break;
         }
         mutex_unlock(&ufile->umap_lock);
         if (!mm)
             return;
 
         /*
          * The umap_lock is nested under mmap_lock since it used within
          * the vma_ops callbacks, so we have to clean the list one mm
          * at a time to get the lock ordering right. Typically there
          * will only be one mm, so no big deal.
          */
         mmap_read_lock(mm);
         mutex_lock(&ufile->umap_lock);
         list_for_each_entry_safe (priv, next_priv, &ufile->umaps,
                       list) {
             struct vm_area_struct *vma = priv->vma;
 
             if (vma->vm_mm != mm)
                 continue;
             list_del_init(&priv->list);
 
             zap_vma_ptes(vma, vma->vm_start,
                      vma->vm_end - vma->vm_start);
 
             if (priv->entry) {
                 rdma_user_mmap_entry_put(priv->entry);
                 priv->entry = NULL;
             }
         }
         mutex_unlock(&ufile->umap_lock);
         mmap_read_unlock(mm);
         mmput(mm);
     }
 }
 
 /*
  * 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 (!refcount_inc_not_zero(&dev->refcount))
         return -ENXIO;
 
     get_device(&dev->dev);
     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;
     }
 
     if (!rdma_dev_access_netns(ib_dev, current->nsproxy->net_ns)) {
         ret = -EPERM;
         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->ops.disassociate_ucontext);
 
     if (module_dependent) {
         if (!try_module_get(ib_dev->ops.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;
     kref_init(&file->ref);
     mutex_init(&file->ucontext_lock);
 
     spin_lock_init(&file->uobjects_lock);
     INIT_LIST_HEAD(&file->uobjects);
     init_rwsem(&file->hw_destroy_rwsem);
     mutex_init(&file->umap_lock);
     INIT_LIST_HEAD(&file->umaps);
 
     filp->private_data = file;
     list_add_tail(&file->list, &dev->uverbs_file_list);
     mutex_unlock(&dev->lists_mutex);
     srcu_read_unlock(&dev->disassociate_srcu, srcu_key);
 
     setup_ufile_idr_uobject(file);
 
     return stream_open(inode, filp);
 
 err_module:
     module_put(ib_dev->ops.owner);
 
 err:
     mutex_unlock(&dev->lists_mutex);
     srcu_read_unlock(&dev->disassociate_srcu, srcu_key);
     if (refcount_dec_and_test(&dev->refcount))
         ib_uverbs_comp_dev(dev);
 
     put_device(&dev->dev);
     return ret;
 }
 
 static int ib_uverbs_close(struct inode *inode, struct file *filp)
 {
     struct ib_uverbs_file *file = filp->private_data;
 
     uverbs_destroy_ufile_hw(file, RDMA_REMOVE_CLOSE);
 
     mutex_lock(&file->device->lists_mutex);
     list_del_init(&file->list);
     mutex_unlock(&file->device->lists_mutex);
 
     kref_put(&file->ref, ib_uverbs_release_file);
 
     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,
     .unlocked_ioctl = ib_uverbs_ioctl,
     .compat_ioctl = compat_ptr_ioctl,
 };
 
 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,
     .unlocked_ioctl = ib_uverbs_ioctl,
     .compat_ioctl = compat_ptr_ioctl,
 };
 
 static int ib_uverbs_get_nl_info(struct ib_device *ibdev, void *client_data,
                  struct ib_client_nl_info *res)
 {
     struct ib_uverbs_device *uverbs_dev = client_data;
     int ret;
 
     if (res->port != -1)
         return -EINVAL;
 
     res->abi = ibdev->ops.uverbs_abi_ver;
     res->cdev = &uverbs_dev->dev;
 
     /*
      * To support DRIVER_ID binding in userspace some of the driver need
      * upgrading to expose their PCI dependent revision information
      * through get_context instead of relying on modalias matching. When
      * the drivers are fixed they can drop this flag.
      */
     if (!ibdev->ops.uverbs_no_driver_id_binding) {
         ret = nla_put_u32(res->nl_msg, RDMA_NLDEV_ATTR_UVERBS_DRIVER_ID,
                   ibdev->ops.driver_id);
         if (ret)
             return ret;
     }
     return 0;
 }
 
 static struct ib_client uverbs_client = {
     .name   = "uverbs",
     .no_kverbs_req = true,
     .add    = ib_uverbs_add_one,
     .remove = ib_uverbs_remove_one,
     .get_nl_info = ib_uverbs_get_nl_info,
 };
 MODULE_ALIAS_RDMA_CLIENT("uverbs");
 
 static ssize_t ibdev_show(struct device *device, struct device_attribute *attr,
               char *buf)
 {
     struct ib_uverbs_device *dev =
             container_of(device, struct ib_uverbs_device, dev);
     int ret = -ENODEV;
     int srcu_key;
     struct ib_device *ib_dev;
 
     srcu_key = srcu_read_lock(&dev->disassociate_srcu);
     ib_dev = srcu_dereference(dev->ib_dev, &dev->disassociate_srcu);
     if (ib_dev)
         ret = sysfs_emit(buf, "%s\n", dev_name(&ib_dev->dev));
     srcu_read_unlock(&dev->disassociate_srcu, srcu_key);
 
     return ret;
 }
 static DEVICE_ATTR_RO(ibdev);
 
 static ssize_t abi_version_show(struct device *device,
                 struct device_attribute *attr, char *buf)
 {
     struct ib_uverbs_device *dev =
             container_of(device, struct ib_uverbs_device, dev);
     int ret = -ENODEV;
     int srcu_key;
     struct ib_device *ib_dev;
 
     srcu_key = srcu_read_lock(&dev->disassociate_srcu);
     ib_dev = srcu_dereference(dev->ib_dev, &dev->disassociate_srcu);
     if (ib_dev)
         ret = sysfs_emit(buf, "%u\n", ib_dev->ops.uverbs_abi_ver);
     srcu_read_unlock(&dev->disassociate_srcu, srcu_key);
 
     return ret;
 }
 static DEVICE_ATTR_RO(abi_version);
 
 static struct attribute *ib_dev_attrs[] = {
     &dev_attr_abi_version.attr,
     &dev_attr_ibdev.attr,
     NULL,
 };
 
 static const struct attribute_group dev_attr_group = {
     .attrs = ib_dev_attrs,
 };
 
 static CLASS_ATTR_STRING(abi_version, S_IRUGO,
              __stringify(IB_USER_VERBS_ABI_VERSION));
 
 static int ib_uverbs_create_uapi(struct ib_device *device,
                  struct ib_uverbs_device *uverbs_dev)
 {
     struct uverbs_api *uapi;
 
     uapi = uverbs_alloc_api(device);
     if (IS_ERR(uapi))
         return PTR_ERR(uapi);
 
     uverbs_dev->uapi = uapi;
     return 0;
 }
 
 static int ib_uverbs_add_one(struct ib_device *device)
 {
     int devnum;
     dev_t base;
     struct ib_uverbs_device *uverbs_dev;
     int ret;
 
     if (!device->ops.alloc_ucontext)
         return -EOPNOTSUPP;
 
     uverbs_dev = kzalloc(sizeof(*uverbs_dev), GFP_KERNEL);
     if (!uverbs_dev)
         return -ENOMEM;
 
     ret = init_srcu_struct(&uverbs_dev->disassociate_srcu);
     if (ret) {
         kfree(uverbs_dev);
         return -ENOMEM;
     }
 
     device_initialize(&uverbs_dev->dev);
     uverbs_dev->dev.class = uverbs_class;
     uverbs_dev->dev.parent = device->dev.parent;
     uverbs_dev->dev.release = ib_uverbs_release_dev;
     uverbs_dev->groups[0] = &dev_attr_group;
     uverbs_dev->dev.groups = uverbs_dev->groups;
     refcount_set(&uverbs_dev->refcount, 1);
     init_completion(&uverbs_dev->comp);
     uverbs_dev->xrcd_tree = RB_ROOT;
     mutex_init(&uverbs_dev->xrcd_tree_mutex);
     mutex_init(&uverbs_dev->lists_mutex);
     INIT_LIST_HEAD(&uverbs_dev->uverbs_file_list);
     rcu_assign_pointer(uverbs_dev->ib_dev, device);
     uverbs_dev->num_comp_vectors = device->num_comp_vectors;
 
     devnum = ida_alloc_max(&uverbs_ida, IB_UVERBS_MAX_DEVICES - 1,
                    GFP_KERNEL);
     if (devnum < 0) {
         ret = -ENOMEM;
         goto err;
     }
     uverbs_dev->devnum = devnum;
     if (devnum >= IB_UVERBS_NUM_FIXED_MINOR)
         base = dynamic_uverbs_dev + devnum - IB_UVERBS_NUM_FIXED_MINOR;
     else
         base = IB_UVERBS_BASE_DEV + devnum;
 
     ret = ib_uverbs_create_uapi(device, uverbs_dev);
     if (ret)
         goto err_uapi;
 
     uverbs_dev->dev.devt = base;
     dev_set_name(&uverbs_dev->dev, "uverbs%d", uverbs_dev->devnum);
 
     cdev_init(&uverbs_dev->cdev,
           device->ops.mmap ? &uverbs_mmap_fops : &uverbs_fops);
     uverbs_dev->cdev.owner = THIS_MODULE;
 
     ret = cdev_device_add(&uverbs_dev->cdev, &uverbs_dev->dev);
     if (ret)
         goto err_uapi;
 
     ib_set_client_data(device, &uverbs_client, uverbs_dev);
     return 0;
 
 err_uapi:
     ida_free(&uverbs_ida, devnum);
 err:
     if (refcount_dec_and_test(&uverbs_dev->refcount))
         ib_uverbs_comp_dev(uverbs_dev);
     wait_for_completion(&uverbs_dev->comp);
     put_device(&uverbs_dev->dev);
     return ret;
 }
 
 static void ib_uverbs_free_hw_resources(struct ib_uverbs_device *uverbs_dev,
                     struct ib_device *ib_dev)
 {
     struct ib_uverbs_file *file;
 
     /* Pending running commands to terminate */
     uverbs_disassociate_api_pre(uverbs_dev);
 
     mutex_lock(&uverbs_dev->lists_mutex);
     while (!list_empty(&uverbs_dev->uverbs_file_list)) {
         file = list_first_entry(&uverbs_dev->uverbs_file_list,
                     struct ib_uverbs_file, list);
         list_del_init(&file->list);
         kref_get(&file->ref);
 
         /* We must release the mutex before going ahead and calling
          * uverbs_cleanup_ufile, as it might end up indirectly calling
          * uverbs_close, for example due to freeing the resources (e.g
          * mmput).
          */
         mutex_unlock(&uverbs_dev->lists_mutex);
 
         uverbs_destroy_ufile_hw(file, RDMA_REMOVE_DRIVER_REMOVE);
         kref_put(&file->ref, ib_uverbs_release_file);
 
         mutex_lock(&uverbs_dev->lists_mutex);
     }
     mutex_unlock(&uverbs_dev->lists_mutex);
 
     uverbs_disassociate_api(uverbs_dev->uapi);
 }
 
 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;
 
     cdev_device_del(&uverbs_dev->cdev, &uverbs_dev->dev);
     ida_free(&uverbs_ida, uverbs_dev->devnum);
 
     if (device->ops.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.
          */
         ib_uverbs_free_hw_resources(uverbs_dev, device);
         wait_clients = 0;
     }
 
     if (refcount_dec_and_test(&uverbs_dev->refcount))
         ib_uverbs_comp_dev(uverbs_dev);
     if (wait_clients)
         wait_for_completion(&uverbs_dev->comp);
 
     put_device(&uverbs_dev->dev);
 }
 
 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_NUM_FIXED_MINOR,
                      "infiniband_verbs");
     if (ret) {
         pr_err("user_verbs: couldn't register device number\n");
         goto out;
     }
 
     ret = alloc_chrdev_region(&dynamic_uverbs_dev, 0,
                   IB_UVERBS_NUM_DYNAMIC_MINOR,
                   "infiniband_verbs");
     if (ret) {
         pr_err("couldn't register dynamic device number\n");
         goto out_alloc;
     }
 
     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(dynamic_uverbs_dev,
                  IB_UVERBS_NUM_DYNAMIC_MINOR);
 
 out_alloc:
     unregister_chrdev_region(IB_UVERBS_BASE_DEV,
                  IB_UVERBS_NUM_FIXED_MINOR);
 
 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_NUM_FIXED_MINOR);
     unregister_chrdev_region(dynamic_uverbs_dev,
                  IB_UVERBS_NUM_DYNAMIC_MINOR);
     mmu_notifier_synchronize();
 }
 
 module_init(ib_uverbs_init);
 module_exit(ib_uverbs_cleanup);

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