splice: only check do_wakeup in splice_to_pipe() for a real pipe

We only ever set do_wakeup to non-zero if the pipe has an inode
backing, so it's pointless to check outside the pipe->inode
check.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

fs/splice.c

@@ -245,7 +245,7 @@ static ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
 		pipe->waiting_writers--;
 	}
 
-	if (pipe->inode)
+	if (pipe->inode) {
 		mutex_unlock(&pipe->inode->i_mutex);
 
 		if (do_wakeup) {
@@ -254,6 +254,7 @@ static ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
 				wake_up_interruptible(&pipe->wait);
 			kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
 		}
+	}
 
 	while (page_nr < spd_pages)
 		page_cache_release(spd->pages[page_nr++]);