1 files changed, 29 insertions, 2 deletions

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 336fdb8ed47b..a89f370fadb5 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -371,9 +371,28 @@ static int ep_call_nested(struct nested_calls *ncalls, int max_nests,
         return error;
 }
 
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+static inline void ep_wake_up_nested(wait_queue_head_t *wqueue,
+                                     unsigned long events, int subclass)
+{
+        unsigned long flags;
+
+        spin_lock_irqsave_nested(&wqueue->lock, flags, subclass);
+        wake_up_locked_poll(wqueue, events);
+        spin_unlock_irqrestore(&wqueue->lock, flags);
+}
+#else
+static inline void ep_wake_up_nested(wait_queue_head_t *wqueue,
+                                     unsigned long events, int subclass)
+{
+        wake_up_poll(wqueue, events);
+}
+#endif
+
 static int ep_poll_wakeup_proc(void *priv, void *cookie, int call_nests)
 {
-        wake_up_nested((wait_queue_head_t *) cookie, 1 + call_nests);
+        ep_wake_up_nested((wait_queue_head_t *) cookie, POLLIN,
+                          1 + call_nests);
         return 0;
 }
 
@@ -783,6 +802,15 @@ static int ep_poll_callback(wait_queue_t *wait, unsigned mode, int sync, void *k
                 goto out_unlock;
 
         /*
+         * Check the events coming with the callback. At this stage, not
+         * every device reports the events in the "key" parameter of the
+         * callback. We need to be able to handle both cases here, hence the
+         * test for "key" != NULL before the event match test.
+         */
+        if (key && !((unsigned long) key & epi->event.events))
+                goto out_unlock;
+
+        /*
          * If we are trasfering events to userspace, we can hold no locks
          * (because we're accessing user memory, and because of linux f_op->poll()
          * semantics). All the events that happens during that period of time are
@@ -1254,7 +1282,6 @@ SYSCALL_DEFINE4(epoll_ctl, int, epfd, int, op, int, fd,
         case EPOLL_CTL_ADD:
                 if (!epi) {
                         epds.events |= POLLERR | POLLHUP;
-
                         error = ep_insert(ep, &epds, tfile, fd);
                 } else
                         error = -EEXIST;