1 files changed, 20 insertions, 31 deletions

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 1ae4542f0bd8..62433cb3d2c2 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -823,7 +823,8 @@ static bool __ep_remove(struct eventpoll *ep, struct epitem *epi, bool force)
 	to_free = NULL;
 	head = file->f_ep;
 	if (head->first == &epi->fllink && !epi->fllink.next) {
-		file->f_ep = NULL;
+		/* See eventpoll_release() for details. */
+		WRITE_ONCE(file->f_ep, NULL);
 		if (!is_file_epoll(file)) {
 			struct epitems_head *v;
 			v = container_of(head, struct epitems_head, epitems);
@@ -1002,7 +1003,7 @@ static struct file *epi_fget(const struct epitem *epi)
 	struct file *file;
 
 	file = epi->ffd.file;
-	if (!atomic_long_inc_not_zero(&file->f_count))
+	if (!file_ref_get(&file->f_ref))
 		file = NULL;
 	return file;
 }
@@ -1372,7 +1373,10 @@ static int ep_poll_callback(wait_queue_entry_t *wait, unsigned mode, int sync, v
 				break;
 			}
 		}
-		wake_up(&ep->wq);
+		if (sync)
+			wake_up_sync(&ep->wq);
+		else
+			wake_up(&ep->wq);
 	}
 	if (waitqueue_active(&ep->poll_wait))
 		pwake++;
@@ -1603,7 +1607,8 @@ allocate:
 			spin_unlock(&file->f_lock);
 			goto allocate;
 		}
-		file->f_ep = head;
+		/* See eventpoll_release() for details. */
+		WRITE_ONCE(file->f_ep, head);
 		to_free = NULL;
 	}
 	hlist_add_head_rcu(&epi->fllink, file->f_ep);
@@ -2254,25 +2259,22 @@ int do_epoll_ctl(int epfd, int op, int fd, struct epoll_event *epds,
 {
 	int error;
 	int full_check = 0;
-	struct fd f, tf;
 	struct eventpoll *ep;
 	struct epitem *epi;
 	struct eventpoll *tep = NULL;
 
-	error = -EBADF;
-	f = fdget(epfd);
-	if (!fd_file(f))
-		goto error_return;
+	CLASS(fd, f)(epfd);
+	if (fd_empty(f))
+		return -EBADF;
 
 	/* Get the "struct file *" for the target file */
-	tf = fdget(fd);
-	if (!fd_file(tf))
-		goto error_fput;
+	CLASS(fd, tf)(fd);
+	if (fd_empty(tf))
+		return -EBADF;
 
 	/* The target file descriptor must support poll */
-	error = -EPERM;
 	if (!file_can_poll(fd_file(tf)))
-		goto error_tgt_fput;
+		return -EPERM;
 
 	/* Check if EPOLLWAKEUP is allowed */
 	if (ep_op_has_event(op))
@@ -2391,12 +2393,6 @@ error_tgt_fput:
 		loop_check_gen++;
 		mutex_unlock(&epnested_mutex);
 	}
-
-	fdput(tf);
-error_fput:
-	fdput(f);
-error_return:
-
 	return error;
 }
 
@@ -2424,8 +2420,6 @@ SYSCALL_DEFINE4(epoll_ctl, int, epfd, int, op, int, fd,
 static int do_epoll_wait(int epfd, struct epoll_event __user *events,
 			 int maxevents, struct timespec64 *to)
 {
-	int error;
-	struct fd f;
 	struct eventpoll *ep;
 
 	/* The maximum number of event must be greater than zero */
@@ -2437,17 +2431,16 @@ static int do_epoll_wait(int epfd, struct epoll_event __user *events,
 		return -EFAULT;
 
 	/* Get the "struct file *" for the eventpoll file */
-	f = fdget(epfd);
-	if (!fd_file(f))
+	CLASS(fd, f)(epfd);
+	if (fd_empty(f))
 		return -EBADF;
 
 	/*
 	 * We have to check that the file structure underneath the fd
 	 * the user passed to us _is_ an eventpoll file.
 	 */
-	error = -EINVAL;
 	if (!is_file_epoll(fd_file(f)))
-		goto error_fput;
+		return -EINVAL;
 
 	/*
 	 * At this point it is safe to assume that the "private_data" contains
@@ -2456,11 +2449,7 @@ static int do_epoll_wait(int epfd, struct epoll_event __user *events,
 	ep = fd_file(f)->private_data;
 
 	/* Time to fish for events ... */
-	error = ep_poll(ep, events, maxevents, to);
-
-error_fput:
-	fdput(f);
-	return error;
+	return ep_poll(ep, events, maxevents, to);
 }
 
 SYSCALL_DEFINE4(epoll_wait, int, epfd, struct epoll_event __user *, events,