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| author | Yufen Yu <yuyufen@huawei.com> | 2019-04-24 18:19:05 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-09-16 09:22:12 +0300 |
| commit | 69409854ba08d3aeb28a3989703381857842e2ab (patch) | |
| tree | 451393411a5a9230d437b9e8388d742fc7c84bb7 /drivers/md/dm-mpath.c | |
| parent | 0fe097012b6ca7d5103eb6905ff6a2b640c78f67 (diff) | |
| download | linux-69409854ba08d3aeb28a3989703381857842e2ab.tar.xz | |
dm mpath: fix missing call of path selector type->end_io
[ Upstream commit 5de719e3d01b4abe0de0d7b857148a880ff2a90b ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/md/dm-mpath.c')
| -rw-r--r-- | drivers/md/dm-mpath.c | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c index baa966e2778c..481e54ded9dc 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -554,8 +554,23 @@ static int multipath_clone_and_map(struct dm_target *ti, struct request *rq, return DM_MAPIO_REMAPPED; } -static void multipath_release_clone(struct request *clone) +static void multipath_release_clone(struct request *clone, + union map_info *map_context) { + if (unlikely(map_context)) { + /* + * non-NULL map_context means caller is still map + * method; must undo multipath_clone_and_map() + */ + struct dm_mpath_io *mpio = get_mpio(map_context); + struct pgpath *pgpath = mpio->pgpath; + + if (pgpath && pgpath->pg->ps.type->end_io) + pgpath->pg->ps.type->end_io(&pgpath->pg->ps, + &pgpath->path, + mpio->nr_bytes); + } + blk_put_request(clone); } |