1 files changed, 32 insertions, 6 deletions

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index ae1dbcf47e97..cde60741cad2 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -94,6 +94,11 @@
 /* Epoll private bits inside the event mask */
 #define EP_PRIVATE_BITS (EPOLLWAKEUP | EPOLLONESHOT | EPOLLET | EPOLLEXCLUSIVE)
 
+#define EPOLLINOUT_BITS (POLLIN | POLLOUT)
+
+#define EPOLLEXCLUSIVE_OK_BITS (EPOLLINOUT_BITS | POLLERR | POLLHUP | \
+                                EPOLLWAKEUP | EPOLLET | EPOLLEXCLUSIVE)
+
 /* Maximum number of nesting allowed inside epoll sets */
 #define EP_MAX_NESTS 4
 
@@ -1068,7 +1073,22 @@ static int ep_poll_callback(wait_queue_t *wait, unsigned mode, int sync, void *k
          * wait list.
          */
         if (waitqueue_active(&ep->wq)) {
-                ewake = 1;
+                if ((epi->event.events & EPOLLEXCLUSIVE) &&
+                                        !((unsigned long)key & POLLFREE)) {
+                        switch ((unsigned long)key & EPOLLINOUT_BITS) {
+                        case POLLIN:
+                                if (epi->event.events & POLLIN)
+                                        ewake = 1;
+                                break;
+                        case POLLOUT:
+                                if (epi->event.events & POLLOUT)
+                                        ewake = 1;
+                                break;
+                        case 0:
+                                ewake = 1;
+                                break;
+                        }
+                }
                 wake_up_locked(&ep->wq);
         }
         if (waitqueue_active(&ep->poll_wait))
@@ -1875,9 +1895,13 @@ SYSCALL_DEFINE4(epoll_ctl, int, epfd, int, op, int, fd,
          * so EPOLLEXCLUSIVE is not allowed for a EPOLL_CTL_MOD operation.
          * Also, we do not currently supported nested exclusive wakeups.
          */
-        if ((epds.events & EPOLLEXCLUSIVE) && (op == EPOLL_CTL_MOD ||
-                (op == EPOLL_CTL_ADD && is_file_epoll(tf.file))))
-                goto error_tgt_fput;
+        if (epds.events & EPOLLEXCLUSIVE) {
+                if (op == EPOLL_CTL_MOD)
+                        goto error_tgt_fput;
+                if (op == EPOLL_CTL_ADD && (is_file_epoll(tf.file) ||
+                                (epds.events & ~EPOLLEXCLUSIVE_OK_BITS)))
+                        goto error_tgt_fput;
+        }
 
         /*
          * At this point it is safe to assume that the "private_data" contains
@@ -1950,8 +1974,10 @@ SYSCALL_DEFINE4(epoll_ctl, int, epfd, int, op, int, fd,
                 break;
         case EPOLL_CTL_MOD:
                 if (epi) {
-                        epds.events |= POLLERR | POLLHUP;
-                        error = ep_modify(ep, epi, &epds);
+                        if (!(epi->event.events & EPOLLEXCLUSIVE)) {
+                                epds.events |= POLLERR | POLLHUP;
+                                error = ep_modify(ep, epi, &epds);
+                        }
                 } else
                         error = -ENOENT;
                 break;