diff options
| author | Mike Snitzer <snitzer@redhat.com> | 2022-02-17 23:40:02 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-05-12 12:23:50 +0200 |
| commit | 786dc86c84348536c77995873a319d98feb49988 (patch) | |
| tree | d23f42f0e79e0ba6ef9c8ef1acff0e111cb16fa1 | |
| parent | ad1393b92e5059218d055bfec8f4946d85ad04c4 (diff) | |
dm: interlock pending dm_io and dm_wait_for_bios_completion
commit 9f6dc633761006f974701d4c88da71ab68670749 upstream.
Commit d208b89401e0 ("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: d208b89401e0 ("dm: fix mempool NULL pointer race when completing IO")
Cc: stable@vger.kernel.org
Co-developed-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/md/dm.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 6fd2899a362a..37b8bb4d80f0 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -681,14 +681,16 @@ static void end_io_acct(struct mapped_device *md, struct bio *bio, { unsigned long duration = jiffies - start_time; - generic_end_io_acct(md->queue, bio_op(bio), &dm_disk(md)->part0, - 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(); + + generic_end_io_acct(md->queue, bio_op(bio), &dm_disk(md)->part0, + start_time); + /* nudge anyone waiting on suspend queue */ if (unlikely(wq_has_sleeper(&md->wait))) wake_up(&md->wait); @@ -2494,6 +2496,8 @@ static int dm_wait_for_completion(struct mapped_device *md, long task_state) } finish_wait(&md->wait, &wait); + smp_rmb(); + return r; } |