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| author |   Laibin Qiu <qiulaibin@huawei.com> | 2022-01-22 19:10:45 +0800 |
|---|---|---|
| committer |   Jens Axboe <axboe@kernel.dk> | 2022-02-17 07:54:03 -0700 |
| commit | e92bc4cd34de2ce454bdea8cd198b8067ee4e123 (patch) | |
| tree | 7429e849741ebcbb669e0543385c0ec9bb69a189 /block/bfq-iosched.c | |
| parent | block: fix surprise removal for drivers calling blk_set_queue_dying (diff) | |
| download | linux-dev-e92bc4cd34de2ce454bdea8cd198b8067ee4e123.tar.xz linux-dev-e92bc4cd34de2ce454bdea8cd198b8067ee4e123.zip | |
block/wbt: fix negative inflight counter when remove scsi device
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>
Diffstat (limited to 'block/bfq-iosched.c')
| -rw-r--r-- | block/bfq-iosched.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 0c612a911696..36a66e97e3c2 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -7018,6 +7018,8 @@ static void bfq_exit_queue(struct elevator_queue *e) spin_unlock_irq(&bfqd->lock); #endif + wbt_enable_default(bfqd->queue); + kfree(bfqd); } |