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| author | Laibin Qiu <qiulaibin@huawei.com> | 2022-01-22 14:10:45 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-02-23 13:59:59 +0300 |
| commit | 20f4ee3c33407db32f0ae73445fc7076c238927c (patch) | |
| tree | 1a2f0107d690dcddd3b655f1a3a6b1af4a5337ca /block/elevator.c | |
| parent | 4cd3281a910a5adf73b2a0a82241dd67844d0b25 (diff) | |
| download | linux-20f4ee3c33407db32f0ae73445fc7076c238927c.tar.xz | |
block/wbt: fix negative inflight counter when remove scsi device
commit e92bc4cd34de2ce454bdea8cd198b8067ee4e123 upstream.
Now that we disable wbt by set WBT_STATE_OFF_DEFAULT in
wbt_disable_default() when switch elevator to bfq. And when
we remove scsi device, wbt will be enabled by wbt_enable_default.
If it become false positive between wbt_wait() and wbt_track()
when submit write request.
The following is the scenario that triggered the problem.
T1 T2 T3
elevator_switch_mq
bfq_init_queue
wbt_disable_default <= Set
rwb->enable_state (OFF)
Submit_bio
blk_mq_make_request
rq_qos_throttle
<= rwb->enable_state (OFF)
scsi_remove_device
sd_remove
del_gendisk
blk_unregister_queue
elv_unregister_queue
wbt_enable_default
<= Set rwb->enable_state (ON)
q_qos_track
<= rwb->enable_state (ON)
^^^^^^ this request will mark WBT_TRACKED without inflight add and will
lead to drop rqw->inflight to -1 in wbt_done() which will trigger IO hung.
Fix this by move wbt_enable_default() from elv_unregister to
bfq_exit_queue(). Only re-enable wbt when bfq exit.
Fixes: 76a8040817b4b ("blk-wbt: make sure throttle is enabled properly")
Remove oneline stale comment, and kill one oneshot local variable.
Signed-off-by: Ming Lei <ming.lei@rehdat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/linux-block/20211214133103.551813-1-qiulaibin@huawei.com/
Signed-off-by: Laibin Qiu <qiulaibin@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'block/elevator.c')
| -rw-r--r-- | block/elevator.c | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/block/elevator.c b/block/elevator.c index 076ba7308e65..78805c74ea8a 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -522,8 +522,6 @@ void elv_unregister_queue(struct request_queue *q) kobject_del(&e->kobj); e->registered = 0; - /* Re-enable throttling in case elevator disabled it */ - wbt_enable_default(q); } } |