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| author | Mike Snitzer <snitzer@redhat.com> | 2022-02-17 23:40:02 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-05-12 12:20:26 +0200 |
| commit | b18fdfb00838594b669749e8f2f622c5df1e43ad (patch) | |
| tree | bd50f8c75f7d0c94729b47471f3448872174f668 | |
| parent | 9e07272cca2ed76f7f6073f4444b1143828c8d87 (diff) | |
| download | linux-b18fdfb00838594b669749e8f2f622c5df1e43ad.tar.gz linux-b18fdfb00838594b669749e8f2f622c5df1e43ad.tar.bz2 linux-b18fdfb00838594b669749e8f2f622c5df1e43ad.zip | |
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 | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 31d02e91e2be..d2ee97cd7d14 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -2475,6 +2475,8 @@ static int dm_wait_for_completion(struct mapped_device *md, long task_state) } finish_wait(&md->wait, &wait); + smp_rmb(); /* paired with atomic_dec_return in end_io_acct */ + return r; } |