diff options
| -rw-r--r-- | fs/eventpoll.c | 19 |
1 files changed, 7 insertions, 12 deletions
diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 64c55037c13..744377c0186 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -435,7 +435,7 @@ static int ep_scan_ready_list(struct eventpoll *ep, /* * We need to lock this because we could be hit by - * eventpoll_release_file() and epoll_ctl(EPOLL_CTL_DEL). + * eventpoll_release_file() and epoll_ctl(). */ mutex_lock(&ep->mtx); @@ -972,15 +972,14 @@ static int ep_modify(struct eventpoll *ep, struct epitem *epi, struct epoll_even { int pwake = 0; unsigned int revents; - unsigned long flags; /* - * Set the new event interest mask before calling f_op->poll(), otherwise - * a potential race might occur. In fact if we do this operation inside - * the lock, an event might happen between the f_op->poll() call and the - * new event set registering. + * Set the new event interest mask before calling f_op->poll(); + * otherwise we might miss an event that happens between the + * f_op->poll() call and the new event set registering. */ epi->event.events = event->events; + epi->event.data = event->data; /* protected by mtx */ /* * Get current event bits. We can safely use the file* here because @@ -988,16 +987,12 @@ static int ep_modify(struct eventpoll *ep, struct epitem *epi, struct epoll_even */ revents = epi->ffd.file->f_op->poll(epi->ffd.file, NULL); - spin_lock_irqsave(&ep->lock, flags); - - /* Copy the data member from inside the lock */ - epi->event.data = event->data; - /* * If the item is "hot" and it is not registered inside the ready * list, push it inside. */ if (revents & event->events) { + spin_lock_irq(&ep->lock); if (!ep_is_linked(&epi->rdllink)) { list_add_tail(&epi->rdllink, &ep->rdllist); @@ -1007,8 +1002,8 @@ static int ep_modify(struct eventpoll *ep, struct epitem *epi, struct epoll_even if (waitqueue_active(&ep->poll_wait)) pwake++; } + spin_unlock_irq(&ep->lock); } - spin_unlock_irqrestore(&ep->lock, flags); /* We have to call this outside the lock */ if (pwake) |