linux-kernel - [PATCH] reiserfs: don't use congestion

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Date:   Wed, 17 Nov 2021 15:34:42 +1100
From:   "NeilBrown" <neilb@...e.de>
To:     Jan Kara <jack@...e.cz>, Jens Axboe <axboe@...nel.dk>
Cc:     reiserfs-devel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] reiserfs: don't use congestion_wait()


Block devices do not, in general, report congestion any more, so this
congestion_wait() is effectively just a sleep.

It isn't entirely clear what is being waited for, but as we only wait
when j_async_throttle is elevated, it seems reasonable to stop waiting
when j_async_throttle becomes zero - or after the same timeout.

So change to use wait_event_event_timeout() for waiting, and
wake_up_var() to signal an end to waiting.

Signed-off-by: NeilBrown <neilb@...e.de>
---

I have no idea who might take this.... Jens and Jan have both landed
reiserfs patches recently...

Thanks,
NeilBrown

 fs/reiserfs/journal.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/fs/reiserfs/journal.c b/fs/reiserfs/journal.c
index 0834b101c316..a3e21160b634 100644
--- a/fs/reiserfs/journal.c
+++ b/fs/reiserfs/journal.c
@@ -951,7 +951,9 @@ static int reiserfs_async_progress_wait(struct super_block *s)
 		int depth;
 
 		depth = reiserfs_write_unlock_nested(s);
-		congestion_wait(BLK_RW_ASYNC, HZ / 10);
+		wait_var_event_timeout(&j->j_async_throttle,
+				       atomic_read(&j->j_async_throttle) == 0,
+				       HZ / 10);
 		reiserfs_write_lock_nested(s, depth);
 	}
 
@@ -1058,7 +1060,8 @@ static int flush_commit_list(struct super_block *s,
 			put_bh(tbh) ;
 		}
 	}
-	atomic_dec(&journal->j_async_throttle);
+	if (atomic_dec_and_test(&journal->j_async_throttle))
+		wake_up_var(&journal->j_async_throttle);
 
 	for (i = 0; i < (jl->j_len + 1); i++) {
 		bn = SB_ONDISK_JOURNAL_1st_BLOCK(s) +
-- 
2.33.1