Commit 843ccf9f authored by David Sterba's avatar David Sterba
Browse files

btrfs: use assertion helpers for spinning writers 



Use the helpers where open coded. On non-debug builds, the warnings will
not trigger and extent_buffer::spining_writers become unused and can be
moved to the appropriate section, saving a few bytes.

Reviewed-by: default avatarNikolay Borisov <nborisov@suse.com>
Reviewed-by: default avatarJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent e4e9fd0f

fs/btrfs/extent_io.c

+4 −1
Original line number Diff line number Diff line
@@ -4682,7 +4682,6 @@ __alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start, 
	atomic_set(&eb->blocking_readers, 0);

	atomic_set(&eb->blocking_writers, 0);

	atomic_set(&eb->spinning_readers, 0);

	atomic_set(&eb->spinning_writers, 0);

	eb->lock_nested = 0;

	init_waitqueue_head(&eb->write_lock_wq);

	init_waitqueue_head(&eb->read_lock_wq);
@@ -4700,6 +4699,10 @@ __alloc_extent_buffer(struct btrfs_fs_info *fs_info, u64 start, 
		> MAX_INLINE_EXTENT_BUFFER_SIZE);

	BUG_ON(len > MAX_INLINE_EXTENT_BUFFER_SIZE);



#ifdef CONFIG_BTRFS_DEBUG

	atomic_set(&eb->spinning_writers, 0);

#endif



	return eb;

}

fs/btrfs/extent_io.h

+1 −1
Original line number Diff line number Diff line
@@ -166,7 +166,6 @@ struct extent_buffer { 
	atomic_t blocking_writers;

	atomic_t blocking_readers;

	atomic_t spinning_readers;

	atomic_t spinning_writers;

	short lock_nested;

	/* >= 0 if eb belongs to a log tree, -1 otherwise */

	short log_index;
@@ -185,6 +184,7 @@ struct extent_buffer { 
	wait_queue_head_t read_lock_wq;

	struct page *pages[INLINE_EXTENT_BUFFER_PAGES];

#ifdef CONFIG_BTRFS_DEBUG

	atomic_t spinning_writers;

	struct list_head leak_list;

#endif

};

fs/btrfs/locking.c

+6 −10
Original line number Diff line number Diff line
@@ -64,8 +64,7 @@ void btrfs_set_lock_blocking_write(struct extent_buffer *eb) 
	if (eb->lock_nested && current->pid == eb->lock_owner)

		return;

	if (atomic_read(&eb->blocking_writers) == 0) {

		WARN_ON(atomic_read(&eb->spinning_writers) != 1);

		atomic_dec(&eb->spinning_writers);

		btrfs_assert_spinning_writers_put(eb);

		btrfs_assert_tree_locked(eb);

		atomic_inc(&eb->blocking_writers);

		write_unlock(&eb->lock);
@@ -101,8 +100,7 @@ void btrfs_clear_lock_blocking_write(struct extent_buffer *eb) 
		return;

	BUG_ON(atomic_read(&eb->blocking_writers) != 1);

	write_lock(&eb->lock);

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

	atomic_inc(&eb->spinning_writers);

	btrfs_assert_spinning_writers_get(eb);

	/* atomic_dec_and_test implies a barrier */

	if (atomic_dec_and_test(&eb->blocking_writers))

		cond_wake_up_nomb(&eb->write_lock_wq);
@@ -200,7 +198,7 @@ int btrfs_try_tree_write_lock(struct extent_buffer *eb) 
		return 0;

	}

	atomic_inc(&eb->write_locks);

	atomic_inc(&eb->spinning_writers);

	btrfs_assert_spinning_writers_get(eb);

	eb->lock_owner = current->pid;

	return 1;

}
@@ -266,8 +264,7 @@ again: 
		write_unlock(&eb->lock);

		goto again;

	}

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

	atomic_inc(&eb->spinning_writers);

	btrfs_assert_spinning_writers_get(eb);

	atomic_inc(&eb->write_locks);

	eb->lock_owner = current->pid;

}
@@ -286,14 +283,13 @@ void btrfs_tree_unlock(struct extent_buffer *eb) 
	atomic_dec(&eb->write_locks);



	if (blockers) {

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

		btrfs_assert_no_spinning_writers(eb);

		atomic_dec(&eb->blocking_writers);

		/* Use the lighter barrier after atomic */

		smp_mb__after_atomic();

		cond_wake_up_nomb(&eb->write_lock_wq);

	} else {

		WARN_ON(atomic_read(&eb->spinning_writers) != 1);

		atomic_dec(&eb->spinning_writers);

		btrfs_assert_spinning_writers_put(eb);

		write_unlock(&eb->lock);

	}

}

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