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| author | Yufen Yu <yuyufen@huawei.com> | 2019-04-24 18:19:05 +0300 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2019-04-25 22:38:52 +0300 |
| commit | 5de719e3d01b4abe0de0d7b857148a880ff2a90b (patch) | |
| tree | 88cacc02c0a64090ce907c8544f6e7e1d0b13421 /drivers/md/dm-rq.c | |
| parent | 873f258becca87f4dd973fe0ba09b88b737c9b14 (diff) | |
| download | linux-5de719e3d01b4abe0de0d7b857148a880ff2a90b.tar.xz | |
dm mpath: fix missing call of path selector type->end_io
After commit 396eaf21ee17 ("blk-mq: improve DM's blk-mq IO merging via
blk_insert_cloned_request feedback"), map_request() will requeue the tio
when issued clone request return BLK_STS_RESOURCE or BLK_STS_DEV_RESOURCE.
Thus, if device driver status is error, a tio may be requeued multiple
times until the return value is not DM_MAPIO_REQUEUE. That means
type->start_io may be called multiple times, while type->end_io is only
called when IO complete.
In fact, even without commit 396eaf21ee17, setup_clone() failure can
also cause tio requeue and associated missed call to type->end_io.
The service-time path selector selects path based on in_flight_size,
which is increased by st_start_io() and decreased by st_end_io().
Missed calls to st_end_io() can lead to in_flight_size count error and
will cause the selector to make the wrong choice. In addition,
queue-length path selector will also be affected.
To fix the problem, call type->end_io in ->release_clone_rq before tio
requeue. map_info is passed to ->release_clone_rq() for map_request()
error path that result in requeue.
Fixes: 396eaf21ee17 ("blk-mq: improve DM's blk-mq IO merging via blk_insert_cloned_request feedback")
Cc: stable@vger.kernl.org
Signed-off-by: Yufen Yu <yuyufen@huawei.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm-rq.c')
| -rw-r--r-- | drivers/md/dm-rq.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c index b66745bd08bb..5f7063f05ae0 100644 --- a/drivers/md/dm-rq.c +++ b/drivers/md/dm-rq.c @@ -168,7 +168,7 @@ static void dm_end_request(struct request *clone, blk_status_t error) struct request *rq = tio->orig; blk_rq_unprep_clone(clone); - tio->ti->type->release_clone_rq(clone); + tio->ti->type->release_clone_rq(clone, NULL); rq_end_stats(md, rq); blk_mq_end_request(rq, error); @@ -201,7 +201,7 @@ static void dm_requeue_original_request(struct dm_rq_target_io *tio, bool delay_ rq_end_stats(md, rq); if (tio->clone) { blk_rq_unprep_clone(tio->clone); - tio->ti->type->release_clone_rq(tio->clone); + tio->ti->type->release_clone_rq(tio->clone, NULL); } dm_mq_delay_requeue_request(rq, delay_ms); @@ -398,7 +398,7 @@ static int map_request(struct dm_rq_target_io *tio) case DM_MAPIO_REMAPPED: if (setup_clone(clone, rq, tio, GFP_ATOMIC)) { /* -ENOMEM */ - ti->type->release_clone_rq(clone); + ti->type->release_clone_rq(clone, &tio->info); return DM_MAPIO_REQUEUE; } @@ -408,7 +408,7 @@ static int map_request(struct dm_rq_target_io *tio) ret = dm_dispatch_clone_request(clone, rq); if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE) { blk_rq_unprep_clone(clone); - tio->ti->type->release_clone_rq(clone); + tio->ti->type->release_clone_rq(clone, &tio->info); tio->clone = NULL; return DM_MAPIO_REQUEUE; } |