kernel/linux.git/block/elevator.c, branch v5.10.257

block/wbt: fix negative inflight counter when remove scsi device

2022-02-23T11:01:04+00:00

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 Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/linux-block/20211214133103.551813-1-qiulaibin@huawei.com/ Signed-off-by: Laibin Qiu Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

block: return ELEVATOR_DISCARD_MERGE if possible

2021-09-15T07:50:28+00:00

[ Upstream commit 866663b7b52d2da267b28e12eed89ee781b8fed1 ] When merging one bio to request, if they are discard IO and the queue supports multi-range discard, we need to return ELEVATOR_DISCARD_MERGE because both block core and related drivers(nvme, virtio-blk) doesn't handle mixed discard io merge(traditional IO merge together with discard merge) well. Fix the issue by returning ELEVATOR_DISCARD_MERGE in this situation, so both blk-mq and drivers just need to handle multi-range discard. Reported-by: Oleksandr Natalenko Signed-off-by: Ming Lei Tested-by: Oleksandr Natalenko Fixes: 2705dfb20947 ("block: fix discard request merge") Link: https://lore.kernel.org/r/20210729034226.1591070-1-ming.lei@redhat.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

block: fix comment and add lockdep assert

2020-10-09T18:34:06+00:00

After commit b89f625e28d4 ("block: don't release queue's sysfs lock during switching elevator"), whole elevator register and unregister function are covered by sysfs_lock. So, remove wrong comment and add lockdep assert. Signed-off-by: Yufen Yu Signed-off-by: Jens Axboe

block: use helper function to test queue register

2020-10-09T18:34:06+00:00

We have defined common interface blk_queue_registered() to test QUEUE_FLAG_REGISTERED. Just use it. Signed-off-by: Yufen Yu Signed-off-by: Jens Axboe

block: remove redundant mq check

2020-10-09T18:34:06+00:00

elv_support_iosched() will check queue_is_mq() for us. So, remove the redundant check to clean code. Signed-off-by: Yufen Yu Signed-off-by: Jens Axboe

block: invoke blk_mq_exit_sched no matter whether have .exit_sched

2020-10-09T18:34:06+00:00

We will register debugfs for scheduler no matter whether it have defined callback funciton .exit_sched. So, blk_mq_exit_sched() is always needed to unregister debugfs. Also, q->elevator should be set as NULL after exiting scheduler. For now, since all register scheduler have defined .exit_sched, it will not cause any actual problem. But It will be more reasonable to do this change. Signed-off-by: Yufen Yu Signed-off-by: Jens Axboe

block: elevator: delete duplicated word and fix typos

2020-07-31T22:29:47+00:00

Drop the repeated word "the". Fix typos of "features" and "specified". Signed-off-by: Randy Dunlap Cc: Jens Axboe Cc: linux-block@vger.kernel.org Signed-off-by: Jens Axboe

Merge branch 'for-linus' into for-5.5/block

2019-11-07T19:27:19+00:00

Pull on for-linus to resolve what otherwise would have been a conflict with the cgroups rstat patchset from Tejun. * for-linus: (942 commits) blkcg: make blkcg_print_stat() print stats only for online blkgs nvme: change nvme_passthru_cmd64 to explicitly mark rsvd nvme-multipath: fix crash in nvme_mpath_clear_ctrl_paths nvme-rdma: fix a segmentation fault during module unload iocost: don't nest spin_lock_irq in ioc_weight_write() io_uring: ensure we clear io_kiocb->result before each issue um-ubd: Entrust re-queue to the upper layers nvme-multipath: remove unused groups_only mode in ana log nvme-multipath: fix possible io hang after ctrl reconnect io_uring: don't touch ctx in setup after ring fd install io_uring: Fix leaked shadow_req Linux 5.4-rc5 riscv: cleanup do_trap_break nbd: verify socket is supported during setup ata: libahci_platform: Fix regulator_get_optional() misuse nbd: handle racing with error'ed out commands nbd: protect cmd->status with cmd->lock io_uring: fix bad inflight accounting for SETUP_IOPOLL|SETUP_SQTHREAD io_uring: used cached copies of sq->dropped and cq->overflow ARM: dts: stm32: relax qspi pins slew-rate for stm32mp157 ...

block: Warn if elevator= parameter is used

2019-11-06T14:16:07+00:00

With transition to blk-mq, the elevator= kernel argument was removed as it makes less and less sense with the current variety of devices. Since this may surprise some users and there are advices on the Internet that still suggest to use it, let's at least warn if the parameter is used. Reviewed-by: Jeff Moyer Signed-off-by: Jan Kara Signed-off-by: Jens Axboe

block: Fix elv_support_iosched()

2019-10-14T19:54:09+00:00

A BIO based request queue does not have a tag_set, which prevent testing for the flag BLK_MQ_F_NO_SCHED indicating that the queue does not require an elevator. This leads to an incorrect initialization of a default elevator in some cases such as BIO based null_blk (queue_mode == BIO) with zoned mode enabled as the default elevator in this case is mq-deadline instead of "none". Fix this by testing for a NULL queue mq_ops field which indicates that the queue is BIO based and should not have an elevator. Reported-by: Shinichiro Kawasaki Reviewed-by: Bob Liu Signed-off-by: Damien Le Moal Signed-off-by: Jens Axboe