linux-kernel - [PATCH 6/6] jbd2: No need to use t_handle_lock in jbd2_journal_wait

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Date:   Thu, 13 Jan 2022 08:56:29 +0530
From:   Ritesh Harjani <riteshh@...ux.ibm.com>
To:     linux-ext4@...r.kernel.org
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        Jan Kara <jack@...e.com>,
        Andreas Dilger <adilger.kernel@...ger.ca>, tytso@....edu,
        Eric Whitney <enwlinux@...il.com>,
        Ritesh Harjani <riteshh@...ux.ibm.com>
Subject: [PATCH 6/6] jbd2: No need to use t_handle_lock in jbd2_journal_wait_updates

Since jbd2_journal_wait_updates() uses waitq based on t_updates atomic_t
variable. So from code review it looks like we don't need to use
t_handle_lock spinlock for checking t_updates value.
Hence this patch gets rid of the spinlock protection in
jbd2_journal_wait_updates()

Signed-off-by: Ritesh Harjani <riteshh@...ux.ibm.com>
---
 include/linux/jbd2.h | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index 34b051aa9009..9bef47622b9d 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -1768,22 +1768,18 @@ static inline void jbd2_journal_wait_updates(journal_t *journal)
 	if (!commit_transaction)
 		return;
 
-	spin_lock(&commit_transaction->t_handle_lock);
 	while (atomic_read(&commit_transaction->t_updates)) {
 		DEFINE_WAIT(wait);
 
 		prepare_to_wait(&journal->j_wait_updates, &wait,
 					TASK_UNINTERRUPTIBLE);
 		if (atomic_read(&commit_transaction->t_updates)) {
-			spin_unlock(&commit_transaction->t_handle_lock);
 			write_unlock(&journal->j_state_lock);
 			schedule();
 			write_lock(&journal->j_state_lock);
-			spin_lock(&commit_transaction->t_handle_lock);
 		}
 		finish_wait(&journal->j_wait_updates, &wait);
 	}
-	spin_unlock(&commit_transaction->t_handle_lock);
 }
 
 /*
-- 
2.31.1