mm/gup: remove try_get_page(), call try_get_compound_head() directly

[linux-2.6-microblaze.git] / fs / pipe.c

diff --git a/fs/pipe.c b/fs/pipe.c
index 8e6ef62..1fa1f52 100644 (file)
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -191,7 +191,7 @@ EXPORT_SYMBOL(generic_pipe_buf_try_steal);
  */
 bool generic_pipe_buf_get(struct pipe_inode_info *pipe, struct pipe_buffer *buf)
 {
-       return try_get_page(buf->page);
+       return try_get_compound_head(buf->page, 1);
 }
 EXPORT_SYMBOL(generic_pipe_buf_get);
 
@@ -363,10 +363,9 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to)
                 * _very_ unlikely case that the pipe was full, but we got
                 * no data.
                 */
-               if (unlikely(was_full)) {
+               if (unlikely(was_full))
                        wake_up_interruptible_sync_poll(&pipe->wr_wait, EPOLLOUT | EPOLLWRNORM);
-                       kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
-               }
+               kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
 
                /*
                 * But because we didn't read anything, at this point we can
@@ -385,12 +384,11 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to)
                wake_next_reader = false;
        __pipe_unlock(pipe);
 
-       if (was_full) {
+       if (was_full)
                wake_up_interruptible_sync_poll(&pipe->wr_wait, EPOLLOUT | EPOLLWRNORM);
-               kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
-       }
        if (wake_next_reader)
                wake_up_interruptible_sync_poll(&pipe->rd_wait, EPOLLIN | EPOLLRDNORM);
+       kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
        if (ret > 0)
                file_accessed(filp);
        return ret;
@@ -444,9 +442,6 @@ 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 +450,9 @@ 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;
@@ -568,10 +563,9 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
                 * become empty while we dropped the lock.
                 */
                __pipe_unlock(pipe);
-               if (was_empty) {
+               if (was_empty)
                        wake_up_interruptible_sync_poll(&pipe->rd_wait, EPOLLIN | EPOLLRDNORM);
-                       kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
-               }
+               kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
                wait_event_interruptible_exclusive(pipe->wr_wait, pipe_writable(pipe));
                __pipe_lock(pipe);
                was_empty = pipe_empty(pipe->head, pipe->tail);
@@ -590,11 +584,13 @@ 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);
-       }
+       kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
        if (wake_next_writer)
                wake_up_interruptible_sync_poll(&pipe->wr_wait, EPOLLOUT | EPOLLWRNORM);
        if (ret > 0 && sb_start_write_trylock(file_inode(filp)->i_sb)) {
@@ -654,6 +650,9 @@ 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.
         *