[IB] uverbs: ABI-breaking fixes for userspace verbs

Introduce new userspace verbs ABI version 3.  This eliminates some
unneeded commands, and adds support for user-created completion
channels.  This cleans up problems with file leaks on error paths, and
also makes sure that file descriptors are always installed into the
correct process.

Signed-off-by: Roland Dreier <rolandd@cisco.com>

3 files changed, 244 insertions, 252 deletions

diff --git a/drivers/infiniband/core/uverbs.h b/drivers/infiniband/core/uverbs.h
index cc124344dd2c..475153e510a9 100644
--- a/drivers/infiniband/core/uverbs.h
+++ b/drivers/infiniband/core/uverbs.h
@@ -53,14 +53,14 @@ struct ib_uverbs_device {
         struct cdev                             dev;
         struct class_device                     class_dev;
         struct ib_device                       *ib_dev;
-        int                                     num_comp;
+        int                                     num_comp_vectors;
 };
 
 struct ib_uverbs_event_file {
         struct kref                             ref;
+        struct file                            *file;
         struct ib_uverbs_file                  *uverbs_file;
         spinlock_t                              lock;
-        int                                     fd;
         int                                     is_async;
         wait_queue_head_t                       poll_wait;
         struct fasync_struct                   *async_queue;
@@ -73,8 +73,7 @@ struct ib_uverbs_file {
         struct ib_uverbs_device                *device;
         struct ib_ucontext                     *ucontext;
         struct ib_event_handler                 event_handler;
-        struct ib_uverbs_event_file             async_file;
-        struct ib_uverbs_event_file             comp_file[1];
+        struct ib_uverbs_event_file            *async_file;
 };
 
 struct ib_uverbs_event {
@@ -110,10 +109,17 @@ extern struct idr ib_uverbs_cq_idr;
 extern struct idr ib_uverbs_qp_idr;
 extern struct idr ib_uverbs_srq_idr;
 
+struct file *ib_uverbs_alloc_event_file(struct ib_uverbs_file *uverbs_file,
+                                        int is_async, int *fd);
+void ib_uverbs_release_event_file(struct kref *ref);
+struct ib_uverbs_event_file *ib_uverbs_lookup_comp_file(int fd);
+
 void ib_uverbs_comp_handler(struct ib_cq *cq, void *cq_context);
 void ib_uverbs_cq_event_handler(struct ib_event *event, void *context_ptr);
 void ib_uverbs_qp_event_handler(struct ib_event *event, void *context_ptr);
 void ib_uverbs_srq_event_handler(struct ib_event *event, void *context_ptr);
+void ib_uverbs_event_handler(struct ib_event_handler *handler,
+                             struct ib_event *event);
 
 int ib_umem_get(struct ib_device *dev, struct ib_umem *mem,
                 void *addr, size_t size, int write);
@@ -125,16 +131,14 @@ void ib_umem_release_on_close(struct ib_device *dev, struct ib_umem *umem);
                                  const char __user *buf, int in_len,    \
                                  int out_len)
 
-IB_UVERBS_DECLARE_CMD(query_params);
 IB_UVERBS_DECLARE_CMD(get_context);
 IB_UVERBS_DECLARE_CMD(query_device);
 IB_UVERBS_DECLARE_CMD(query_port);
-IB_UVERBS_DECLARE_CMD(query_gid);
-IB_UVERBS_DECLARE_CMD(query_pkey);
 IB_UVERBS_DECLARE_CMD(alloc_pd);
 IB_UVERBS_DECLARE_CMD(dealloc_pd);
 IB_UVERBS_DECLARE_CMD(reg_mr);
 IB_UVERBS_DECLARE_CMD(dereg_mr);
+IB_UVERBS_DECLARE_CMD(create_comp_channel);
 IB_UVERBS_DECLARE_CMD(create_cq);
 IB_UVERBS_DECLARE_CMD(destroy_cq);
 IB_UVERBS_DECLARE_CMD(create_qp);
diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
index 562445165d2b..79b60c3dc8d0 100644
--- a/drivers/infiniband/core/uverbs_cmd.c
+++ b/drivers/infiniband/core/uverbs_cmd.c
@@ -33,6 +33,8 @@
  * $Id: uverbs_cmd.c 2708 2005-06-24 17:27:21Z roland $
  */
 
+#include <linux/file.h>
+
 #include <asm/uaccess.h>
 
 #include "uverbs.h"
@@ -45,29 +47,6 @@
                 (udata)->outlen = (olen);                               \
         } while (0)
 
-ssize_t ib_uverbs_query_params(struct ib_uverbs_file *file,
-                               const char __user *buf,
-                               int in_len, int out_len)
-{
-        struct ib_uverbs_query_params      cmd;
-        struct ib_uverbs_query_params_resp resp;
-
-        if (out_len < sizeof resp)
-                return -ENOSPC;
-
-        if (copy_from_user(&cmd, buf, sizeof cmd))
-                return -EFAULT;
-
-        memset(&resp, 0, sizeof resp);
-
-        resp.num_cq_events = file->device->num_comp;
-
-        if (copy_to_user((void __user *) (unsigned long) cmd.response, &resp, sizeof resp))
-            return -EFAULT;
-
-        return in_len;
-}
-
 ssize_t ib_uverbs_get_context(struct ib_uverbs_file *file,
                               const char __user *buf,
                               int in_len, int out_len)
@@ -77,7 +56,7 @@ ssize_t ib_uverbs_get_context(struct ib_uverbs_file *file,
         struct ib_udata                   udata;
         struct ib_device                 *ibdev = file->device->ib_dev;
         struct ib_ucontext               *ucontext;
-        int i;
+        struct file                      *filp;
         int ret;
 
         if (out_len < sizeof resp)
@@ -110,26 +89,42 @@ ssize_t ib_uverbs_get_context(struct ib_uverbs_file *file,
         INIT_LIST_HEAD(&ucontext->srq_list);
         INIT_LIST_HEAD(&ucontext->ah_list);
 
-        resp.async_fd = file->async_file.fd;
-        for (i = 0; i < file->device->num_comp; ++i)
-                if (copy_to_user((void __user *) (unsigned long) cmd.cq_fd_tab +
-                                 i * sizeof (__u32),
-                                 &file->comp_file[i].fd, sizeof (__u32))) {
-                        ret = -EFAULT;
-                        goto err_free;
-                }
+        resp.num_comp_vectors = file->device->num_comp_vectors;
+
+        filp = ib_uverbs_alloc_event_file(file, 1, &resp.async_fd);
+        if (IS_ERR(filp)) {
+                ret = PTR_ERR(filp);
+                goto err_free;
+        }
 
         if (copy_to_user((void __user *) (unsigned long) cmd.response,
                          &resp, sizeof resp)) {
                 ret = -EFAULT;
-                goto err_free;
+                goto err_file;
         }
 
-        file->ucontext = ucontext;
+        file->async_file = filp->private_data;
+
+        INIT_IB_EVENT_HANDLER(&file->event_handler, file->device->ib_dev,
+                              ib_uverbs_event_handler);
+        ret = ib_register_event_handler(&file->event_handler);
+        if (ret)
+                goto err_file;
+
+        kref_get(&file->async_file->ref);
+        kref_get(&file->ref);
+        file->ucontext   = ucontext;
+
+        fd_install(resp.async_fd, filp);
+
         up(&file->mutex);
 
         return in_len;
 
+err_file:
+        put_unused_fd(resp.async_fd);
+        fput(filp);
+
 err_free:
         ibdev->dealloc_ucontext(ucontext);
 
@@ -255,62 +250,6 @@ ssize_t ib_uverbs_query_port(struct ib_uverbs_file *file,
         return in_len;
 }
 
-ssize_t ib_uverbs_query_gid(struct ib_uverbs_file *file,
-                            const char __user *buf,
-                            int in_len, int out_len)
-{
-        struct ib_uverbs_query_gid      cmd;
-        struct ib_uverbs_query_gid_resp resp;
-        int                             ret;
-
-        if (out_len < sizeof resp)
-                return -ENOSPC;
-
-        if (copy_from_user(&cmd, buf, sizeof cmd))
-                return -EFAULT;
-
-        memset(&resp, 0, sizeof resp);
-
-        ret = ib_query_gid(file->device->ib_dev, cmd.port_num, cmd.index,
-                           (union ib_gid *) resp.gid);
-        if (ret)
-                return ret;
-
-        if (copy_to_user((void __user *) (unsigned long) cmd.response,
-                         &resp, sizeof resp))
-                return -EFAULT;
-
-        return in_len;
-}
-
-ssize_t ib_uverbs_query_pkey(struct ib_uverbs_file *file,
-                             const char __user *buf,
-                             int in_len, int out_len)
-{
-        struct ib_uverbs_query_pkey      cmd;
-        struct ib_uverbs_query_pkey_resp resp;
-        int                              ret;
-
-        if (out_len < sizeof resp)
-                return -ENOSPC;
-
-        if (copy_from_user(&cmd, buf, sizeof cmd))
-                return -EFAULT;
-
-        memset(&resp, 0, sizeof resp);
-
-        ret = ib_query_pkey(file->device->ib_dev, cmd.port_num, cmd.index,
-                            &resp.pkey);
-        if (ret)
-                return ret;
-
-        if (copy_to_user((void __user *) (unsigned long) cmd.response,
-                         &resp, sizeof resp))
-                return -EFAULT;
-
-        return in_len;
-}
-
 ssize_t ib_uverbs_alloc_pd(struct ib_uverbs_file *file,
                            const char __user *buf,
                            int in_len, int out_len)
@@ -595,6 +534,35 @@ out:
         return ret ? ret : in_len;
 }
 
+ssize_t ib_uverbs_create_comp_channel(struct ib_uverbs_file *file,
+                                      const char __user *buf, int in_len,
+                                      int out_len)
+{
+        struct ib_uverbs_create_comp_channel       cmd;
+        struct ib_uverbs_create_comp_channel_resp  resp;
+        struct file                               *filp;
+
+        if (out_len < sizeof resp)
+                return -ENOSPC;
+
+        if (copy_from_user(&cmd, buf, sizeof cmd))
+                return -EFAULT;
+
+        filp = ib_uverbs_alloc_event_file(file, 0, &resp.fd);
+        if (IS_ERR(filp))
+                return PTR_ERR(filp);
+
+        if (copy_to_user((void __user *) (unsigned long) cmd.response,
+                         &resp, sizeof resp)) {
+                put_unused_fd(resp.fd);
+                fput(filp);
+                return -EFAULT;
+        }
+
+        fd_install(resp.fd, filp);
+        return in_len;
+}
+
 ssize_t ib_uverbs_create_cq(struct ib_uverbs_file *file,
                             const char __user *buf, int in_len,
                             int out_len)
@@ -603,6 +571,7 @@ ssize_t ib_uverbs_create_cq(struct ib_uverbs_file *file,
         struct ib_uverbs_create_cq_resp resp;
         struct ib_udata                 udata;
         struct ib_ucq_object           *uobj;
+        struct ib_uverbs_event_file    *ev_file = NULL;
         struct ib_cq                   *cq;
         int                             ret;
 
@@ -616,9 +585,12 @@ ssize_t ib_uverbs_create_cq(struct ib_uverbs_file *file,
                    (unsigned long) cmd.response + sizeof resp,
                    in_len - sizeof cmd, out_len - sizeof resp);
 
-        if (cmd.event_handler >= file->device->num_comp)
+        if (cmd.comp_vector >= file->device->num_comp_vectors)
                 return -EINVAL;
 
+        if (cmd.comp_channel >= 0)
+                ev_file = ib_uverbs_lookup_comp_file(cmd.comp_channel);
+
         uobj = kmalloc(sizeof *uobj, GFP_KERNEL);
         if (!uobj)
                 return -ENOMEM;
@@ -641,7 +613,7 @@ ssize_t ib_uverbs_create_cq(struct ib_uverbs_file *file,
         cq->uobject       = &uobj->uobject;
         cq->comp_handler  = ib_uverbs_comp_handler;
         cq->event_handler = ib_uverbs_cq_event_handler;
-        cq->cq_context    = file;
+        cq->cq_context    = ev_file;
         atomic_set(&cq->usecnt, 0);
 
 retry:
@@ -700,6 +672,7 @@ ssize_t ib_uverbs_destroy_cq(struct ib_uverbs_file *file,
         struct ib_uverbs_destroy_cq_resp resp;
         struct ib_cq                    *cq;
         struct ib_ucq_object            *uobj;
+        struct ib_uverbs_event_file     *ev_file;
         struct ib_uverbs_event          *evt, *tmp;
         u64                              user_handle;
         int                              ret = -EINVAL;
@@ -716,7 +689,8 @@ ssize_t ib_uverbs_destroy_cq(struct ib_uverbs_file *file,
                 goto out;
 
         user_handle = cq->uobject->user_handle;
-        uobj = container_of(cq->uobject, struct ib_ucq_object, uobject);
+        uobj        = container_of(cq->uobject, struct ib_ucq_object, uobject);
+        ev_file     = cq->cq_context;
 
         ret = ib_destroy_cq(cq);
         if (ret)
@@ -728,19 +702,23 @@ ssize_t ib_uverbs_destroy_cq(struct ib_uverbs_file *file,
         list_del(&uobj->uobject.list);
         up(&file->mutex);
 
-        spin_lock_irq(&file->comp_file[0].lock);
-        list_for_each_entry_safe(evt, tmp, &uobj->comp_list, obj_list) {
-                list_del(&evt->list);
-                kfree(evt);
+        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_unlock_irq(&file->comp_file[0].lock);
 
-        spin_lock_irq(&file->async_file.lock);
+        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);
+        spin_unlock_irq(&file->async_file->lock);
 
         resp.comp_events_reported  = uobj->comp_events_reported;
         resp.async_events_reported = uobj->async_events_reported;
@@ -1005,12 +983,12 @@ ssize_t ib_uverbs_destroy_qp(struct ib_uverbs_file *file,
         list_del(&uobj->uobject.list);
         up(&file->mutex);
 
-        spin_lock_irq(&file->async_file.lock);
+        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);
+        spin_unlock_irq(&file->async_file->lock);
 
         resp.events_reported = uobj->events_reported;
 
@@ -1243,12 +1221,12 @@ ssize_t ib_uverbs_destroy_srq(struct ib_uverbs_file *file,
         list_del(&uobj->uobject.list);
         up(&file->mutex);
 
-        spin_lock_irq(&file->async_file.lock);
+        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);
+        spin_unlock_irq(&file->async_file->lock);
 
         resp.events_reported = uobj->events_reported;
 
diff --git a/drivers/infiniband/core/uverbs_main.c b/drivers/infiniband/core/uverbs_main.c
index 12511808de21..e7058fbc607d 100644
--- a/drivers/infiniband/core/uverbs_main.c
+++ b/drivers/infiniband/core/uverbs_main.c
@@ -77,26 +77,24 @@ static DECLARE_BITMAP(dev_map, IB_UVERBS_MAX_DEVICES);
 static ssize_t (*uverbs_cmd_table[])(struct ib_uverbs_file *file,
                                      const char __user *buf, int in_len,
                                      int out_len) = {
-        [IB_USER_VERBS_CMD_QUERY_PARAMS]  = ib_uverbs_query_params,
-        [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_QUERY_GID]     = ib_uverbs_query_gid,
-        [IB_USER_VERBS_CMD_QUERY_PKEY]    = ib_uverbs_query_pkey,
-        [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_DEREG_MR]      = ib_uverbs_dereg_mr,
-        [IB_USER_VERBS_CMD_CREATE_CQ]     = ib_uverbs_create_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_MODIFY_QP]     = ib_uverbs_modify_qp,
-        [IB_USER_VERBS_CMD_DESTROY_QP]    = ib_uverbs_destroy_qp,
-        [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_DESTROY_SRQ]   = ib_uverbs_destroy_srq,
+        [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_DEREG_MR]            = ib_uverbs_dereg_mr,
+        [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_DESTROY_CQ]          = ib_uverbs_destroy_cq,
+        [IB_USER_VERBS_CMD_CREATE_QP]           = ib_uverbs_create_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_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_DESTROY_SRQ]         = ib_uverbs_destroy_srq,
 };
 
 static struct vfsmount *uverbs_event_mnt;
@@ -188,25 +186,19 @@ static ssize_t ib_uverbs_event_read(struct file *filp, char __user *buf,
 
         spin_lock_irq(&file->lock);
 
-        while (list_empty(&file->event_list) && file->fd >= 0) {
+        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) ||
-                                             file->fd < 0))
+                                             !list_empty(&file->event_list)))
                         return -ERESTARTSYS;
 
                 spin_lock_irq(&file->lock);
         }
 
-        if (file->fd < 0) {
-                spin_unlock_irq(&file->lock);
-                return -ENODEV;
-        }
-
         event = list_entry(file->event_list.next, struct ib_uverbs_event, list);
 
         if (file->is_async)
@@ -248,26 +240,19 @@ static unsigned int ib_uverbs_event_poll(struct file *filp,
         poll_wait(filp, &file->poll_wait, wait);
 
         spin_lock_irq(&file->lock);
-        if (file->fd < 0)
-                pollflags = POLLERR;
-        else if (!list_empty(&file->event_list))
+        if (!list_empty(&file->event_list))
                 pollflags = POLLIN | POLLRDNORM;
         spin_unlock_irq(&file->lock);
 
         return pollflags;
 }
 
-static void ib_uverbs_event_release(struct ib_uverbs_event_file *file)
+void ib_uverbs_release_event_file(struct kref *ref)
 {
-        struct ib_uverbs_event *entry, *tmp;
+        struct ib_uverbs_event_file *file =
+                container_of(ref, struct ib_uverbs_event_file, ref);
 
-        spin_lock_irq(&file->lock);
-        if (file->fd != -1) {
-                file->fd = -1;
-                list_for_each_entry_safe(entry, tmp, &file->event_list, list)
-                        kfree(entry);
-        }
-        spin_unlock_irq(&file->lock);
+        kfree(file);
 }
 
 static int ib_uverbs_event_fasync(int fd, struct file *filp, int on)
@@ -280,21 +265,30 @@ static int ib_uverbs_event_fasync(int fd, struct file *filp, int on)
 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;
+
+        spin_lock_irq(&file->lock);
+        file->file = NULL;
+        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);
 
-        ib_uverbs_event_release(file);
         ib_uverbs_event_fasync(-1, filp, 0);
-        kref_put(&file->uverbs_file->ref, ib_uverbs_release_file);
+
+        if (file->is_async) {
+                ib_unregister_event_handler(&file->uverbs_file->event_handler);
+                kref_put(&file->uverbs_file->ref, ib_uverbs_release_file);
+        }
+        kref_put(&file->ref, ib_uverbs_release_event_file);
 
         return 0;
 }
 
 static struct file_operations uverbs_event_fops = {
-        /*
-         * No .owner field since we artificially create event files,
-         * so there is no increment to the module reference count in
-         * the open path.  All event files come from a uverbs command
-         * file, which already takes a module reference, so this is OK.
-         */
+        .owner   = THIS_MODULE,
         .read    = ib_uverbs_event_read,
         .poll    = ib_uverbs_event_poll,
         .release = ib_uverbs_event_close,
@@ -303,10 +297,19 @@ static struct file_operations uverbs_event_fops = {
 
 void ib_uverbs_comp_handler(struct ib_cq *cq, void *cq_context)
 {
-        struct ib_uverbs_file  *file = cq_context;
-        struct ib_ucq_object   *uobj;
-        struct ib_uverbs_event *entry;
-        unsigned long           flags;
+        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->file) {
+                spin_unlock_irqrestore(&file->lock, flags);
+                return;
+        }
 
         entry = kmalloc(sizeof *entry, GFP_ATOMIC);
         if (!entry)
@@ -317,13 +320,12 @@ void ib_uverbs_comp_handler(struct ib_cq *cq, void *cq_context)
         entry->desc.comp.cq_handle = cq->uobject->user_handle;
         entry->counter             = &uobj->comp_events_reported;
 
-        spin_lock_irqsave(&file->comp_file[0].lock, flags);
-        list_add_tail(&entry->list, &file->comp_file[0].event_list);
+        list_add_tail(&entry->list, &file->event_list);
         list_add_tail(&entry->obj_list, &uobj->comp_list);
-        spin_unlock_irqrestore(&file->comp_file[0].lock, flags);
+        spin_unlock_irqrestore(&file->lock, flags);
 
-        wake_up_interruptible(&file->comp_file[0].poll_wait);
-        kill_fasync(&file->comp_file[0].async_queue, SIGIO, POLL_IN);
+        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,
@@ -334,6 +336,12 @@ static void ib_uverbs_async_handler(struct ib_uverbs_file *file,
         struct ib_uverbs_event *entry;
         unsigned long flags;
 
+        spin_lock_irqsave(&file->async_file->lock, flags);
+        if (!file->async_file->file) {
+                spin_unlock_irqrestore(&file->async_file->lock, flags);
+                return;
+        }
+
         entry = kmalloc(sizeof *entry, GFP_ATOMIC);
         if (!entry)
                 return;
@@ -342,24 +350,24 @@ static void ib_uverbs_async_handler(struct ib_uverbs_file *file,
         entry->desc.async.event_type = event;
         entry->counter               = counter;
 
-        spin_lock_irqsave(&file->async_file.lock, flags);
-        list_add_tail(&entry->list, &file->async_file.event_list);
+        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);
+        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);
+        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_uverbs_event_file *ev_file = context_ptr;
         struct ib_ucq_object *uobj;
 
         uobj = container_of(event->element.cq->uobject,
                             struct ib_ucq_object, uobject);
 
-        ib_uverbs_async_handler(context_ptr, uobj->uobject.user_handle,
+        ib_uverbs_async_handler(ev_file->uverbs_file, uobj->uobject.user_handle,
                                 event->event, &uobj->async_list,
                                 &uobj->async_events_reported);
                                 
@@ -389,8 +397,8 @@ void ib_uverbs_srq_event_handler(struct ib_event *event, void *context_ptr)
                                 &uobj->events_reported);
 }
 
-static void ib_uverbs_event_handler(struct ib_event_handler *handler,
-                                    struct ib_event *event)
+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);
@@ -399,38 +407,90 @@ static void ib_uverbs_event_handler(struct ib_event_handler *handler,
                                 NULL, NULL);
 }
 
-static int ib_uverbs_event_init(struct ib_uverbs_event_file *file,
-                                struct ib_uverbs_file *uverbs_file)
+struct file *ib_uverbs_alloc_event_file(struct ib_uverbs_file *uverbs_file,
+                                        int is_async, int *fd)
 {
+        struct ib_uverbs_event_file *ev_file;
         struct file *filp;
+        int ret;
 
-        spin_lock_init(&file->lock);
-        INIT_LIST_HEAD(&file->event_list);
-        init_waitqueue_head(&file->poll_wait);
-        file->uverbs_file = uverbs_file;
-        file->async_queue = NULL;
-
-        file->fd = get_unused_fd();
-        if (file->fd < 0)
-                return file->fd;
+        ev_file = kmalloc(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;
+        ev_file->async_queue = NULL;
+        ev_file->is_async    = is_async;
+
+        *fd = get_unused_fd();
+        if (*fd < 0) {
+                ret = *fd;
+                goto err;
+        }
 
         filp = get_empty_filp();
         if (!filp) {
-                put_unused_fd(file->fd);
-                return -ENFILE;
+                ret = -ENFILE;
+                goto err_fd;
         }
 
-        filp->f_op         = &uverbs_event_fops;
+        ev_file->file      = filp;
+
+        /*
+         * fops_get() can't fail here, because we're coming from a
+         * system call on a uverbs file, which will already have a
+         * module reference.
+         */
+        filp->f_op         = fops_get(&uverbs_event_fops);
         filp->f_vfsmnt     = mntget(uverbs_event_mnt);
         filp->f_dentry     = dget(uverbs_event_mnt->mnt_root);
         filp->f_mapping    = filp->f_dentry->d_inode->i_mapping;
         filp->f_flags      = O_RDONLY;
         filp->f_mode       = FMODE_READ;
-        filp->private_data = file;
+        filp->private_data = ev_file;
 
-        fd_install(file->fd, filp);
+        return filp;
 
-        return 0;
+err_fd:
+        put_unused_fd(*fd);
+
+err:
+        kfree(ev_file);
+        return ERR_PTR(ret);
+}
+
+/*
+ * 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 file *filp;
+
+        filp = fget(fd);
+        if (!filp)
+                return NULL;
+
+        if (filp->f_op != &uverbs_event_fops)
+                goto out;
+
+        ev_file = filp->private_data;
+        if (ev_file->is_async) {
+                ev_file = NULL;
+                goto out;
+        }
+
+        kref_get(&ev_file->ref);
+
+out:
+        fput(filp);
+        return ev_file;
 }
 
 static ssize_t ib_uverbs_write(struct file *filp, const char __user *buf,
@@ -453,8 +513,7 @@ static ssize_t ib_uverbs_write(struct file *filp, const char __user *buf,
             !uverbs_cmd_table[hdr.command])
                 return -EINVAL;
 
-        if (!file->ucontext                               &&
-            hdr.command != IB_USER_VERBS_CMD_QUERY_PARAMS &&
+        if (!file->ucontext &&
             hdr.command != IB_USER_VERBS_CMD_GET_CONTEXT)
                 return -EINVAL;
 
@@ -477,82 +536,33 @@ static int ib_uverbs_open(struct inode *inode, struct file *filp)
         struct ib_uverbs_device *dev =
                 container_of(inode->i_cdev, struct ib_uverbs_device, dev);
         struct ib_uverbs_file *file;
-        int i = 0;
-        int ret;
 
         if (!try_module_get(dev->ib_dev->owner))
                 return -ENODEV;
 
-        file = kmalloc(sizeof *file +
-                       (dev->num_comp - 1) * sizeof (struct ib_uverbs_event_file),
-                       GFP_KERNEL);
+        file = kmalloc(sizeof *file, GFP_KERNEL);
         if (!file) {
-                ret = -ENOMEM;
-                goto err;
+                module_put(dev->ib_dev->owner);
+                return -ENOMEM;
         }
 
-        file->device = dev;
+        file->device   = dev;
+        file->ucontext = NULL;
         kref_init(&file->ref);
         init_MUTEX(&file->mutex);
 
-        file->ucontext = NULL;
-
-        kref_get(&file->ref);
-        ret = ib_uverbs_event_init(&file->async_file, file);
-        if (ret)
-                goto err_kref;
-
-        file->async_file.is_async = 1;
-
-        for (i = 0; i < dev->num_comp; ++i) {
-                kref_get(&file->ref);
-                ret = ib_uverbs_event_init(&file->comp_file[i], file);
-                if (ret)
-                        goto err_async;
-                file->comp_file[i].is_async = 0;
-        }
-
-
         filp->private_data = file;
 
-        INIT_IB_EVENT_HANDLER(&file->event_handler, dev->ib_dev,
-                              ib_uverbs_event_handler);
-        if (ib_register_event_handler(&file->event_handler))
-                goto err_async;
-
         return 0;
-
-err_async:
-        while (i--)
-                ib_uverbs_event_release(&file->comp_file[i]);
-
-        ib_uverbs_event_release(&file->async_file);
-
-err_kref:
-        /*
-         * One extra kref_put() because we took a reference before the
-         * event file creation that failed and got us here.
-         */
-        kref_put(&file->ref, ib_uverbs_release_file);
-        kref_put(&file->ref, ib_uverbs_release_file);
-
-err:
-        module_put(dev->ib_dev->owner);
-        return ret;
 }
 
 static int ib_uverbs_close(struct inode *inode, struct file *filp)
 {
         struct ib_uverbs_file *file = filp->private_data;
-        int i;
 
-        ib_unregister_event_handler(&file->event_handler);
-        ib_uverbs_event_release(&file->async_file);
         ib_dealloc_ucontext(file->ucontext);
 
-        for (i = 0; i < file->device->num_comp; ++i)
-                ib_uverbs_event_release(&file->comp_file[i]);
-
+        kref_put(&file->async_file->ref, ib_uverbs_release_event_file);
         kref_put(&file->ref, ib_uverbs_release_file);
 
         return 0;
@@ -631,8 +641,8 @@ static void ib_uverbs_add_one(struct ib_device *device)
         set_bit(uverbs_dev->devnum, dev_map);
         spin_unlock(&map_lock);
 
-        uverbs_dev->ib_dev   = device;
-        uverbs_dev->num_comp = 1;
+        uverbs_dev->ib_dev           = device;
+        uverbs_dev->num_comp_vectors = 1;
 
         if (device->mmap)
                 cdev_init(&uverbs_dev->dev, &uverbs_mmap_fops);