This is a note to let you know that I've just added the patch titled
md/raid10: fix the condition to call bio_end_io_acct()
to the 6.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
md-raid10-fix-the-condition-to-call-bio_end_io_acct.patch
and it can be found in the queue-6.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 75d6713a879b1ca713ab30b4a0d3da59e8e445fc
Author: Li Nan <linan122@xxxxxxxxxx>
Date: Fri Jun 9 17:43:20 2023 +0800
md/raid10: fix the condition to call bio_end_io_acct()
[ Upstream commit 125bfc7cd750e68c99f1d446e2c22abea08c237f ]
/sys/block/[device]/queue/iostats is used to control whether to count io
stat. Write 0 to it will clear queue_flags QUEUE_FLAG_IO_STAT which means
iostats is disabled. If we disable iostats and later endable it, the io
issued during this period will be counted incorrectly, inflight will be
decreased to -1.
//T1 set iostats
echo 0 > /sys/block/md0/queue/iostats
clear QUEUE_FLAG_IO_STAT
//T2 issue io
if (QUEUE_FLAG_IO_STAT) -> false
bio_start_io_acct
inflight++
echo 1 > /sys/block/md0/queue/iostats
set QUEUE_FLAG_IO_STAT
//T3 io end
if (QUEUE_FLAG_IO_STAT) -> true
bio_end_io_acct
inflight-- -> -1
Also, if iostats is enabled while issuing io but disabled while io end,
inflight will never be decreased.
Fix it by checking start_time when io end. If start_time is not 0, call
bio_end_io_acct().
Fixes: 528bc2cf2fcc ("md/raid10: enable io accounting")
Signed-off-by: Li Nan <linan122@xxxxxxxxxx>
Signed-off-by: Song Liu <song@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230609094320.2397604-1-linan666@xxxxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 9d11a52367d17..9d23963496194 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -325,7 +325,7 @@ static void raid_end_bio_io(struct r10bio *r10_bio)
if (!test_bit(R10BIO_Uptodate, &r10_bio->state))
bio->bi_status = BLK_STS_IOERR;
- if (blk_queue_io_stat(bio->bi_bdev->bd_disk->queue))
+ if (r10_bio->start_time)
bio_end_io_acct(bio, r10_bio->start_time);
bio_endio(bio);
/*
