Commit db8a1f7a authored by Mike Snitzer's avatar Mike Snitzer Committed by Zheng Zengkai
Browse files

dm: interlock pending dm_io and dm_wait_for_bios_completion 

stable inclusion
from stable-v5.10.115
commit 7676a5b99f3da170d42d3e457cd7ff8c82001dd1
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5IZ9C

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=7676a5b99f3da170d42d3e457cd7ff8c82001dd1



--------------------------------

commit 9f6dc633 upstream.

Commit d208b894 ("dm: fix mempool NULL pointer race when
completing IO") didn't go far enough.

When bio_end_io_acct ends the count of in-flight I/Os may reach zero
and the DM device may be suspended. There is a possibility that the
suspend races with dm_stats_account_io.

Fix this by adding percpu "pending_io" counters to track outstanding
dm_io. Move kicking of suspend queue to dm_io_dec_pending(). Also,
rename md_in_flight_bios() to dm_in_flight_bios() and update it to
iterate all pending_io counters.

Fixes: d208b894 ("dm: fix mempool NULL pointer race when completing IO")
Cc: stable@vger.kernel.org
Co-developed-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
Acked-by: default avatarXie XiuQi <xiexiuqi@huawei.com>
parent 2525d77c

drivers/md/dm.c

+6 −2
Original line number Diff line number Diff line
@@ -599,13 +599,15 @@ static void end_io_acct(struct mapped_device *md, struct bio *bio, 
{

	unsigned long duration = jiffies - start_time;



	bio_end_io_acct(bio, start_time);



	if (unlikely(dm_stats_used(&md->stats)))

		dm_stats_account_io(&md->stats, bio_data_dir(bio),

				    bio->bi_iter.bi_sector, bio_sectors(bio),

				    true, duration, stats_aux);



	smp_wmb();



	bio_end_io_acct(bio, start_time);



	/* nudge anyone waiting on suspend queue */

	if (unlikely(wq_has_sleeper(&md->wait)))

		wake_up(&md->wait);
@@ -2330,6 +2332,8 @@ static int dm_wait_for_bios_completion(struct mapped_device *md, long task_state 
	}

	finish_wait(&md->wait, &wait);



	smp_rmb();



	return r;

}