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authorYufen Yu <yuyufen@huawei.com>2019-04-24 18:19:05 +0300
committerMike Snitzer <snitzer@redhat.com>2019-04-25 22:38:52 +0300
commit5de719e3d01b4abe0de0d7b857148a880ff2a90b (patch)
tree88cacc02c0a64090ce907c8544f6e7e1d0b13421 /drivers/md/dm-target.c
parent873f258becca87f4dd973fe0ba09b88b737c9b14 (diff)
downloadlinux-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-target.c')
-rw-r--r--drivers/md/dm-target.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/md/dm-target.c b/drivers/md/dm-target.c
index 314d17ca6466..64dd0b34fcf4 100644
--- a/drivers/md/dm-target.c
+++ b/drivers/md/dm-target.c
@@ -136,7 +136,8 @@ static int io_err_clone_and_map_rq(struct dm_target *ti, struct request *rq,
return DM_MAPIO_KILL;
}
-static void io_err_release_clone_rq(struct request *clone)
+static void io_err_release_clone_rq(struct request *clone,
+ union map_info *map_context)
{
}