NFC: Use GFP_USER for user-controlled kmalloc

[karo-tx-linux.git] / fs / eventpoll.c

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 1e009cad8d5cac61832ebb3916033780f2fec1a6..ae1dbcf47e979d48b67ee83e1ec413e4d119a48b 100644 (file)
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -92,7 +92,7 @@
  */
 
 /* Epoll private bits inside the event mask */
-#define EP_PRIVATE_BITS (EPOLLWAKEUP | EPOLLONESHOT | EPOLLET)
+#define EP_PRIVATE_BITS (EPOLLWAKEUP | EPOLLONESHOT | EPOLLET | EPOLLEXCLUSIVE)
 
 /* Maximum number of nesting allowed inside epoll sets */
 #define EP_MAX_NESTS 4
@@ -1002,6 +1002,7 @@ static int ep_poll_callback(wait_queue_t *wait, unsigned mode, int sync, void *k
        unsigned long flags;
        struct epitem *epi = ep_item_from_wait(wait);
        struct eventpoll *ep = epi->ep;
+       int ewake = 0;
 
        if ((unsigned long)key & POLLFREE) {
                ep_pwq_from_wait(wait)->whead = NULL;
@@ -1066,8 +1067,10 @@ static int ep_poll_callback(wait_queue_t *wait, unsigned mode, int sync, void *k
         * Wake up ( if active ) both the eventpoll wait list and the ->poll()
         * wait list.
         */
-       if (waitqueue_active(&ep->wq))
+       if (waitqueue_active(&ep->wq)) {
+               ewake = 1;
                wake_up_locked(&ep->wq);
+       }
        if (waitqueue_active(&ep->poll_wait))
                pwake++;
 
@@ -1078,6 +1081,9 @@ out_unlock:
        if (pwake)
                ep_poll_safewake(&ep->poll_wait);
 
+       if (epi->event.events & EPOLLEXCLUSIVE)
+               return ewake;
+
        return 1;
 }
 
@@ -1095,7 +1101,10 @@ static void ep_ptable_queue_proc(struct file *file, wait_queue_head_t *whead,
                init_waitqueue_func_entry(&pwq->wait, ep_poll_callback);
                pwq->whead = whead;
                pwq->base = epi;
-               add_wait_queue(whead, &pwq->wait);
+               if (epi->event.events & EPOLLEXCLUSIVE)
+                       add_wait_queue_exclusive(whead, &pwq->wait);
+               else
+                       add_wait_queue(whead, &pwq->wait);
                list_add_tail(&pwq->llink, &epi->pwqlist);
                epi->nwait++;
        } else {
@@ -1861,6 +1870,15 @@ SYSCALL_DEFINE4(epoll_ctl, int, epfd, int, op, int, fd,
        if (f.file == tf.file || !is_file_epoll(f.file))
                goto error_tgt_fput;
 
+       /*
+        * epoll adds to the wakeup queue at EPOLL_CTL_ADD time only,
+        * 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;
+
        /*
         * At this point it is safe to assume that the "private_data" contains
         * our own data structure.