Commit ee863954 authored by David Sterba's avatar David Sterba
Browse files

btrfs: comment the rest of implicit barriers before waitqueue_active 



There are atomic operations that imply the barrier for waitqueue_active
mixed in an if-condition.

Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 779adf0f

fs/btrfs/delayed-inode.c

+4 −0
Original line number Diff line number Diff line
@@ -463,6 +463,10 @@ static int __btrfs_add_delayed_deletion_item(struct btrfs_delayed_node *node, 
static void finish_one_item(struct btrfs_delayed_root *delayed_root)

{

	int seq = atomic_inc_return(&delayed_root->items_seq);



	/*

	 * atomic_dec_return implies a barrier for waitqueue_active

	 */

	if ((atomic_dec_return(&delayed_root->items) <

	    BTRFS_DELAYED_BACKGROUND || seq % BTRFS_DELAYED_BATCH == 0) &&

	    waitqueue_active(&delayed_root->wait))

fs/btrfs/disk-io.c

+3 −0
Original line number Diff line number Diff line
@@ -802,6 +802,9 @@ static void run_one_async_done(struct btrfs_work *work) 
	limit = btrfs_async_submit_limit(fs_info);

	limit = limit * 2 / 3;



	/*

	 * atomic_dec_return implies a barrier for waitqueue_active

	 */

	if (atomic_dec_return(&fs_info->nr_async_submits) < limit &&

	    waitqueue_active(&fs_info->async_submit_wait))

		wake_up(&fs_info->async_submit_wait);

fs/btrfs/inode.c

+3 −0
Original line number Diff line number Diff line
@@ -1096,6 +1096,9 @@ static noinline void async_cow_submit(struct btrfs_work *work) 
	nr_pages = (async_cow->end - async_cow->start + PAGE_CACHE_SIZE) >>

		PAGE_CACHE_SHIFT;



	/*

	 * atomic_sub_return implies a barrier for waitqueue_active

	 */

	if (atomic_sub_return(nr_pages, &root->fs_info->async_delalloc_pages) <

	    5 * 1024 * 1024 &&

	    waitqueue_active(&root->fs_info->async_submit_wait))

fs/btrfs/locking.c

+9 −0
Original line number Diff line number Diff line
@@ -79,6 +79,9 @@ void btrfs_clear_lock_blocking_rw(struct extent_buffer *eb, int rw) 
		write_lock(&eb->lock);

		WARN_ON(atomic_read(&eb->spinning_writers));

		atomic_inc(&eb->spinning_writers);

		/*

		 * atomic_dec_and_test implies a barrier for waitqueue_active

		 */

		if (atomic_dec_and_test(&eb->blocking_writers) &&

		    waitqueue_active(&eb->write_lock_wq))

			wake_up(&eb->write_lock_wq);
@@ -86,6 +89,9 @@ void btrfs_clear_lock_blocking_rw(struct extent_buffer *eb, int rw) 
		BUG_ON(atomic_read(&eb->blocking_readers) == 0);

		read_lock(&eb->lock);

		atomic_inc(&eb->spinning_readers);

		/*

		 * atomic_dec_and_test implies a barrier for waitqueue_active

		 */

		if (atomic_dec_and_test(&eb->blocking_readers) &&

		    waitqueue_active(&eb->read_lock_wq))

			wake_up(&eb->read_lock_wq);
@@ -229,6 +235,9 @@ void btrfs_tree_read_unlock_blocking(struct extent_buffer *eb) 
	}

	btrfs_assert_tree_read_locked(eb);

	WARN_ON(atomic_read(&eb->blocking_readers) == 0);

	/*

	 * atomic_dec_and_test implies a barrier for waitqueue_active

	 */

	if (atomic_dec_and_test(&eb->blocking_readers) &&

	    waitqueue_active(&eb->read_lock_wq))

		wake_up(&eb->read_lock_wq);

fs/btrfs/volumes.c

+3 −0
Original line number Diff line number Diff line
@@ -345,6 +345,9 @@ static noinline void run_scheduled_bios(struct btrfs_device *device) 
		pending = pending->bi_next;

		cur->bi_next = NULL;



		/*

		 * atomic_dec_return implies a barrier for waitqueue_active

		 */

		if (atomic_dec_return(&fs_info->nr_async_bios) < limit &&

		    waitqueue_active(&fs_info->async_submit_wait))

			wake_up(&fs_info->async_submit_wait);