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: NMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: NMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>

drivers/md/dm.c

@@ -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;
 }