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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 /drivers/md
parent873f258becca87f4dd973fe0ba09b88b737c9b14 (diff)
downloadlinux-5de719e3d01b4abe0de0d7b857148a880ff2a90b.tar.gz
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')
-rw-r--r--drivers/md/dm-mpath.c17
-rw-r--r--drivers/md/dm-rq.c8
-rw-r--r--drivers/md/dm-target.c3
3 files changed, 22 insertions, 6 deletions
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 2ee5e357a0a7..07cfef67c0ba 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -544,8 +544,23 @@ 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);
}
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;
}
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)
{
}