X-Git-Url: http://git.monstr.eu/?a=blobdiff_plain;f=fs%2Fpipe.c;h=678dee2a8228d403b2fc13b55322242b259d9f6c;hb=8f96a5bfa1503e0a5f3c78d51e993a1794d4aff1;hp=8e6ef62aeb1c63cab8b45d11e9d73e6dbfdee93c;hpb=611ffd8acc4b06e606325ca727c891ce70adcaa6;p=linux-2.6-microblaze.git

diff --git a/fs/pipe.c b/fs/pipe.c
index 8e6ef62aeb1c..678dee2a8228 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -444,9 +444,6 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
 #endif
 
 	/*
-	 * Epoll nonsensically wants a wakeup whether the pipe
-	 * was already empty or not.
-	 *
 	 * If it wasn't empty we try to merge new data into
 	 * the last buffer.
 	 *
@@ -455,9 +452,9 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
 	 * spanning multiple pages.
 	 */
 	head = pipe->head;
-	was_empty = true;
+	was_empty = pipe_empty(head, pipe->tail);
 	chars = total_len & (PAGE_SIZE-1);
-	if (chars && !pipe_empty(head, pipe->tail)) {
+	if (chars && !was_empty) {
 		unsigned int mask = pipe->ring_size - 1;
 		struct pipe_buffer *buf = &pipe->bufs[(head - 1) & mask];
 		int offset = buf->offset + buf->len;
@@ -590,8 +587,11 @@ out:
 	 * This is particularly important for small writes, because of
 	 * how (for example) the GNU make jobserver uses small writes to
 	 * wake up pending jobs
+	 *
+	 * Epoll nonsensically wants a wakeup whether the pipe
+	 * was already empty or not.
 	 */
-	if (was_empty) {
+	if (was_empty || pipe->poll_usage) {
 		wake_up_interruptible_sync_poll(&pipe->rd_wait, EPOLLIN | EPOLLRDNORM);
 		kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
 	}
@@ -654,6 +654,9 @@ pipe_poll(struct file *filp, poll_table *wait)
 	struct pipe_inode_info *pipe = filp->private_data;
 	unsigned int head, tail;
 
+	/* Epoll has some historical nasty semantics, this enables them */
+	pipe->poll_usage = 1;
+
 	/*
 	 * Reading pipe state only -- no need for acquiring the semaphore.
 	 *