block/wbt: fix negative inflight counter when remove scsi device
commite92bc4cd34
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:76a8040817
("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>
This commit is contained in:
Родитель
a22b213139
Коммит
4b9c861a58
|
@ -6878,6 +6878,8 @@ static void bfq_exit_queue(struct elevator_queue *e)
|
|||
spin_unlock_irq(&bfqd->lock);
|
||||
#endif
|
||||
|
||||
wbt_enable_default(bfqd->queue);
|
||||
|
||||
kfree(bfqd);
|
||||
}
|
||||
|
||||
|
|
|
@ -523,8 +523,6 @@ 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);
|
||||
}
|
||||
}
|
||||
|
||||
|
|
Загрузка…
Ссылка в новой задаче