[PATCH 2/2] fs: jbd2: use clear_and_wake_up_bit() in journal_end_buffer_io_sync()

[Agatha Isabelle Moreira]

Use `clear_and_wake_up_bit()` in `journal_end_buffer_io_sync()`, since
the helper was introduced in 'commit 8236b0ae31c83 ("bdi: wake up
concurrent wb_shutdown() callers.")' as a generic way of doing the same
sequence of operations:
	clear_bit_unlock();
	smp_mb__after_atomic();
	wake_up_bit();

The helper was first implemented to avoid bugs caused by forgetting to
call `wake_up_bit()` after `clear_bit_unlock()`.

Since `journal_end_buffer_io_sync()` was first introduced by 'commit
470decc613ab2 ("jbd2: initial copy of files from jbd")' and last
modified in this operation by 'commit 4e857c58efeb9 ("arch: Mass
conversion of smp_mb__*()")', years before `clear_and_wake_up_bit()`, it
still uses the open-coded sequence.

Replace the open-coded sequence with the helper to avoid duplicate code
and reduce code paths to maintain.

Suggested-by: shuo chen <1289151713@xxxxxx>
Link: https://lore.kernel.org/kernelnewbies/agzoqV835-co4kAN@guidai/T/#t
Signed-off-by: Agatha Isabelle Moreira <code@xxxxxxxxxx>
---
 fs/jbd2/commit.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 8cf61e7185c4..b647fde76e49 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -39,9 +39,7 @@ static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
 	else
 		clear_buffer_uptodate(bh);
 	if (orig_bh) {
-		clear_bit_unlock(BH_Shadow, &orig_bh->b_state);
-		smp_mb__after_atomic();
-		wake_up_bit(&orig_bh->b_state, BH_Shadow);
+		clear_and_wake_up_bit(BH_Shadow, &orig_bh->b_state);
 	}
 	unlock_buffer(bh);
 }
-- 
2.53.0