pipe: use event aware wakeups
Davide Libenzi [Thu, 13 Jan 2011 01:00:25 +0000 (17:00 -0800)]
Send the events the wakeup refers to, so that epoll, and even the new poll
code in fs/select.c can avoid wakeups if the events do not match the
requested set.

Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/pipe.c

index 68f1f8e..04151e2 100644 (file)
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -441,7 +441,7 @@ redo:
                        break;
                }
                if (do_wakeup) {
-                       wake_up_interruptible_sync(&pipe->wait);
+                       wake_up_interruptible_sync_poll(&pipe->wait, POLLOUT);
                        kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
                }
                pipe_wait(pipe);
@@ -450,7 +450,7 @@ redo:
 
        /* Signal writers asynchronously that there is more room. */
        if (do_wakeup) {
-               wake_up_interruptible_sync(&pipe->wait);
+               wake_up_interruptible_sync_poll(&pipe->wait, POLLOUT);
                kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
        }
        if (ret > 0)
@@ -612,7 +612,7 @@ redo2:
                        break;
                }
                if (do_wakeup) {
-                       wake_up_interruptible_sync(&pipe->wait);
+                       wake_up_interruptible_sync_poll(&pipe->wait, POLLIN);
                        kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
                        do_wakeup = 0;
                }
@@ -623,7 +623,7 @@ redo2:
 out:
        mutex_unlock(&inode->i_mutex);
        if (do_wakeup) {
-               wake_up_interruptible_sync(&pipe->wait);
+               wake_up_interruptible_sync_poll(&pipe->wait, POLLIN);
                kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
        }
        if (ret > 0)
@@ -715,7 +715,7 @@ pipe_release(struct inode *inode, int decr, int decw)
        if (!pipe->readers && !pipe->writers) {
                free_pipe_info(inode);
        } else {
-               wake_up_interruptible_sync(&pipe->wait);
+               wake_up_interruptible_sync_poll(&pipe->wait, POLLIN | POLLOUT);
                kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
                kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
        }