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authorYufen Yu <yuyufen@huawei.com>2019-04-24 23:19:05 +0800
committerMike Snitzer <snitzer@redhat.com>2019-04-25 15:38:52 -0400
commit5de719e3d01b4abe0de0d7b857148a880ff2a90b (patch)
tree88cacc02c0a64090ce907c8544f6e7e1d0b13421 /include/linux/device-mapper.h
parent873f258becca87f4dd973fe0ba09b88b737c9b14 (diff)
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 'include/linux/device-mapper.h')
-rw-r--r--include/linux/device-mapper.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index b0672756d056..e1f51d607cc5 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -62,7 +62,8 @@ typedef int (*dm_clone_and_map_request_fn) (struct dm_target *ti,
struct request *rq,
union map_info *map_context,
struct request **clone);
-typedef void (*dm_release_clone_request_fn) (struct request *clone);
+typedef void (*dm_release_clone_request_fn) (struct request *clone,
+ union map_info *map_context);
/*
* Returns: