dm: fix dm_rq_target_io leak on faults with .request_fn DM w/ blk-mq paths
Using request-based DM mpath configured with the following stacking
(.request_fn DM mpath ontop of scsi-mq paths):
echo Y > /sys/module/scsi_mod/parameters/use_blk_mq
echo N > /sys/module/dm_mod/parameters/use_blk_mq
'struct dm_rq_target_io' would leak if a request is requeued before a
blk-mq clone is allocated (or fails to allocate). free_rq_tio()
wasn't being called.
kmemleak reported:
unreferenced object 0xffff8800b90b98c0 (size 112):
comm "kworker/7:1H", pid 5692, jiffies
4295056109 (age 78.589s)
hex dump (first 32 bytes):
00 d0 5c 2c 03 88 ff ff 40 00 bf 01 00 c9 ff ff ..\,....@.......
e0 d9 b1 34 00 88 ff ff 00 00 00 00 00 00 00 00 ...4............
backtrace:
[<
ffffffff81672b6e>] kmemleak_alloc+0x4e/0xb0
[<
ffffffff811dbb63>] kmem_cache_alloc+0xc3/0x1e0
[<
ffffffff8117eae5>] mempool_alloc_slab+0x15/0x20
[<
ffffffff8117ec1e>] mempool_alloc+0x6e/0x170
[<
ffffffffa00029ac>] dm_old_prep_fn+0x3c/0x180 [dm_mod]
[<
ffffffff812fbd78>] blk_peek_request+0x168/0x290
[<
ffffffffa0003e62>] dm_request_fn+0xb2/0x1b0 [dm_mod]
[<
ffffffff812f66e3>] __blk_run_queue+0x33/0x40
[<
ffffffff812f9585>] blk_delay_work+0x25/0x40
[<
ffffffff81096fff>] process_one_work+0x14f/0x3d0
[<
ffffffff81097715>] worker_thread+0x125/0x4b0
[<
ffffffff8109ce88>] kthread+0xd8/0xf0
[<
ffffffff8167cb8f>] ret_from_fork+0x3f/0x70
[<
ffffffffffffffff>] 0xffffffffffffffff
crash> struct -o dm_rq_target_io
struct dm_rq_target_io {
...
}
SIZE: 112
Fixes:
e5863d9ad7 ("dm: allocate requests in target when stacking on blk-mq devices")
Cc: stable@vger.kernel.org # 4.0+
Signed-off-by: Mike Snitzer <snitzer@redhat.com>