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* blk-mq: set default elevator as deadline in case of hctx shared tagsetMing Lei2021-04-071-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | Yanhui found that write performance is degraded a lot after applying hctx shared tagset on one test machine with megaraid_sas. And turns out it is caused by none scheduler which becomes default elevator caused by hctx shared tagset patchset. Given more scsi HBAs will apply hctx shared tagset, and the similar performance exists for them too. So keep previous behavior by still using default mq-deadline for queues which apply hctx shared tagset, just like before. Fixes: 32bc15afed04 ("blk-mq: Facilitate a shared sbitmap per tagset") Reported-by: Yanhui Ma <yama@redhat.com> Cc: John Garry <john.garry@huawei.com> Cc: Hannes Reinecke <hare@suse.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: John Garry <john.garry@huawei.com> Link: https://lore.kernel.org/r/20210406031933.767228-1-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: fix comment and add lockdep assertYufen Yu2020-10-091-10/+4
| | | | | | | | | | 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 <yuyufen@huawei.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: use helper function to test queue registerYufen Yu2020-10-091-1/+1
| | | | | | | | We have defined common interface blk_queue_registered() to test QUEUE_FLAG_REGISTERED. Just use it. Signed-off-by: Yufen Yu <yuyufen@huawei.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: remove redundant mq checkYufen Yu2020-10-091-2/+2
| | | | | | | | elv_support_iosched() will check queue_is_mq() for us. So, remove the redundant check to clean code. Signed-off-by: Yufen Yu <yuyufen@huawei.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: invoke blk_mq_exit_sched no matter whether have .exit_schedYufen Yu2020-10-091-2/+1
| | | | | | | | | | | | | | 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 <yuyufen@huawei.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: elevator: delete duplicated word and fix typosRandy Dunlap2020-08-011-2/+2
| | | | | | | | | | Drop the repeated word "the". Fix typos of "features" and "specified". Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: linux-block@vger.kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
* Merge branch 'for-linus' into for-5.5/blockJens Axboe2019-11-071-1/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: Fix elv_support_iosched()Damien Le Moal2019-10-141-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <shinichiro.kawasaki@wdc.com> Reviewed-by: Bob Liu <bob.liu@oracle.com> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | block: Warn if elevator= parameter is usedJan Kara2019-11-061-0/+9
|/ | | | | | | | | | | 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 <jmoyer@redhat.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: don't release queue's sysfs lock during switching elevatorMing Lei2019-09-261-30/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cecf5d87ff20 ("block: split .sysfs_lock into two locks") starts to release & acquire sysfs_lock before registering/un-registering elevator queue during switching elevator for avoiding potential deadlock from showing & storing 'queue/iosched' attributes and removing elevator's kobject. Turns out there isn't such deadlock because 'q->sysfs_lock' isn't required in .show & .store of queue/iosched's attributes, and just elevator's sysfs lock is acquired in elv_iosched_store() and elv_iosched_show(). So it is safe to hold queue's sysfs lock when registering/un-registering elevator queue. The biggest issue is that commit cecf5d87ff20 assumes that concurrent write on 'queue/scheduler' can't happen. However, this assumption isn't true, because kernfs_fop_write() only guarantees that concurrent write aren't called on the same open file, but the write could be from different open on the file. So we can't release & re-acquire queue's sysfs lock during switching elevator, otherwise use-after-free on elevator could be triggered. Fixes the issue by not releasing queue's sysfs lock during switching elevator. Fixes: cecf5d87ff20 ("block: split .sysfs_lock into two locks") Cc: Christoph Hellwig <hch@infradead.org> Cc: Hannes Reinecke <hare@suse.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Mike Snitzer <snitzer@redhat.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: fix elevator_get_by_features()Jens Axboe2019-09-061-6/+7
| | | | | | | | | The lookup logic is broken - 'e' will never be NULL, even if the list is empty. Maintain lookup hit in a separate variable instead. Fixes: a0958ba7fcdc ("block: Improve default elevator selection") Reported-by: Julia Lawall <julia.lawall@lip6.fr> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: Delay default elevator initializationDamien Le Moal2019-09-061-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When elevator_init_mq() is called from blk_mq_init_allocated_queue(), the only information known about the device is the number of hardware queues as the block device scan by the device driver is not completed yet for most drivers. The device type and elevator required features are not set yet, preventing to correctly select the default elevator most suitable for the device. This currently affects all multi-queue zoned block devices which default to the "none" elevator instead of the required "mq-deadline" elevator. These drives currently include host-managed SMR disks connected to a smartpqi HBA and null_blk block devices with zoned mode enabled. Upcoming NVMe Zoned Namespace devices will also be affected. Fix this by adding the boolean elevator_init argument to blk_mq_init_allocated_queue() to control the execution of elevator_init_mq(). Two cases exist: 1) elevator_init = false is used for calls to blk_mq_init_allocated_queue() within blk_mq_init_queue(). In this case, a call to elevator_init_mq() is added to __device_add_disk(), resulting in the delayed initialization of the queue elevator after the device driver finished probing the device information. This effectively allows elevator_init_mq() access to more information about the device. 2) elevator_init = true preserves the current behavior of initializing the elevator directly from blk_mq_init_allocated_queue(). This case is used for the special request based DM devices where the device gendisk is created before the queue initialization and device information (e.g. queue limits) is already known when the queue initialization is executed. Additionally, to make sure that the elevator initialization is never done while requests are in-flight (there should be none when the device driver calls device_add_disk()), freeze and quiesce the device request queue before calling blk_mq_init_sched() in elevator_init_mq(). Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: Improve default elevator selectionDamien Le Moal2019-09-061-7/+44
| | | | | | | | | | | | | | | | | For block devices that do not specify required features, preserve the current default elevator selection (mq-deadline for single queue devices, none for multi-queue devices). However, for devices specifying required features (e.g. zoned block devices ELEVATOR_F_ZBD_SEQ_WRITE feature), select the first available elevator providing the required features. In all cases, default to "none" if no elevator is available or if the initialization of the default elevator fails. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: Introduce elevator featuresDamien Le Moal2019-09-061-11/+38
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Introduce the definition of elevator features through the elevator_features flags in the elevator_type structure. Each flag can represent a feature supported by an elevator. The first feature defined by this patch is support for zoned block device sequential write constraint with the flag ELEVATOR_F_ZBD_SEQ_WRITE, which is implemented by the mq-deadline elevator using zone write locking. Other possible features are IO priorities, write hints, latency targets or single-LUN dual-actuator disks (for which the elevator could maintain one LBA ordered list per actuator). The required_elevator_features field is also added to the request_queue structure to allow a device driver to specify elevator feature flags that an elevator must support for the correct operation of the device (e.g. device drivers for zoned block devices can have the ELEVATOR_F_ZBD_SEQ_WRITE flag as a required feature). The helper function blk_queue_required_elevator_features() is defined for setting this new field. With these two new fields in place, the elevator functions elevator_match() and elevator_find() are modified to allow a user to set only an elevator with a set of features that satisfies the device required features. Elevators not matching the device requirements are not shown in the device sysfs queue/scheduler file to prevent their use. The "none" elevator can always be selected as before. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: Change elevator_init_mq() to always succeedDamien Le Moal2019-09-061-11/+12
| | | | | | | | | | | | | | | | | | | If the default elevator chosen is mq-deadline, elevator_init_mq() may return an error if mq-deadline initialization fails, leading to blk_mq_init_allocated_queue() returning an error, which in turn will cause the block device initialization to fail and the device not being exposed. Instead of taking such extreme measure, handle mq-deadline initialization failures in the same manner as when mq-deadline is not available (no module to load), that is, default to the "none" scheduler. With this change, elevator_init_mq() return type can be changed to void. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: Cleanup elevator_init_mq() useDamien Le Moal2019-09-061-10/+13
| | | | | | | | | | | | | | | Instead of checking a queue tag_set BLK_MQ_F_NO_SCHED flag before calling elevator_init_mq() to make sure that the queue supports IO scheduling, use the elevator.c function elv_support_iosched() in elevator_init_mq(). This does not introduce any functional change but ensure that elevator_init_mq() does the right thing based on the queue settings. Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: elevator.c: Remove now unused elevator= argumentMarcos Paulo de Souza2019-09-031-14/+0
| | | | | | | | | | | | | | | Since the inclusion of blk-mq, elevator argument was not being considered anymore, and it's utility died long with the legacy IO path, now removed too. Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Bob Liu <bob.liu@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Marcos Paulo de Souza <marcos.souza.org@gmail.com> Fold with doc removal patch. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: split .sysfs_lock into two locksMing Lei2019-08-271-8/+47
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The kernfs built-in lock of 'kn->count' is held in sysfs .show/.store path. Meantime, inside block's .show/.store callback, q->sysfs_lock is required. However, when mq & iosched kobjects are removed via blk_mq_unregister_dev() & elv_unregister_queue(), q->sysfs_lock is held too. This way causes AB-BA lock because the kernfs built-in lock of 'kn-count' is required inside kobject_del() too, see the lockdep warning[1]. On the other hand, it isn't necessary to acquire q->sysfs_lock for both blk_mq_unregister_dev() & elv_unregister_queue() because clearing REGISTERED flag prevents storing to 'queue/scheduler' from being happened. Also sysfs write(store) is exclusive, so no necessary to hold the lock for elv_unregister_queue() when it is called in switching elevator path. So split .sysfs_lock into two: one is still named as .sysfs_lock for covering sync .store, the other one is named as .sysfs_dir_lock for covering kobjects and related status change. sysfs itself can handle the race between add/remove kobjects and showing/storing attributes under kobjects. For switching scheduler via storing to 'queue/scheduler', we use the queue flag of QUEUE_FLAG_REGISTERED with .sysfs_lock for avoiding the race, then we can avoid to hold .sysfs_lock during removing/adding kobjects. [1] lockdep warning ====================================================== WARNING: possible circular locking dependency detected 5.3.0-rc3-00044-g73277fc75ea0 #1380 Not tainted ------------------------------------------------------ rmmod/777 is trying to acquire lock: 00000000ac50e981 (kn->count#202){++++}, at: kernfs_remove_by_name_ns+0x59/0x72 but task is already holding lock: 00000000fb16ae21 (&q->sysfs_lock){+.+.}, at: blk_unregister_queue+0x78/0x10b which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&q->sysfs_lock){+.+.}: __lock_acquire+0x95f/0xa2f lock_acquire+0x1b4/0x1e8 __mutex_lock+0x14a/0xa9b blk_mq_hw_sysfs_show+0x63/0xb6 sysfs_kf_seq_show+0x11f/0x196 seq_read+0x2cd/0x5f2 vfs_read+0xc7/0x18c ksys_read+0xc4/0x13e do_syscall_64+0xa7/0x295 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (kn->count#202){++++}: check_prev_add+0x5d2/0xc45 validate_chain+0xed3/0xf94 __lock_acquire+0x95f/0xa2f lock_acquire+0x1b4/0x1e8 __kernfs_remove+0x237/0x40b kernfs_remove_by_name_ns+0x59/0x72 remove_files+0x61/0x96 sysfs_remove_group+0x81/0xa4 sysfs_remove_groups+0x3b/0x44 kobject_del+0x44/0x94 blk_mq_unregister_dev+0x83/0xdd blk_unregister_queue+0xa0/0x10b del_gendisk+0x259/0x3fa null_del_dev+0x8b/0x1c3 [null_blk] null_exit+0x5c/0x95 [null_blk] __se_sys_delete_module+0x204/0x337 do_syscall_64+0xa7/0x295 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&q->sysfs_lock); lock(kn->count#202); lock(&q->sysfs_lock); lock(kn->count#202); *** DEADLOCK *** 2 locks held by rmmod/777: #0: 00000000e69bd9de (&lock){+.+.}, at: null_exit+0x2e/0x95 [null_blk] #1: 00000000fb16ae21 (&q->sysfs_lock){+.+.}, at: blk_unregister_queue+0x78/0x10b stack backtrace: CPU: 0 PID: 777 Comm: rmmod Not tainted 5.3.0-rc3-00044-g73277fc75ea0 #1380 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS ?-20180724_192412-buildhw-07.phx4 Call Trace: dump_stack+0x9a/0xe6 check_noncircular+0x207/0x251 ? print_circular_bug+0x32a/0x32a ? find_usage_backwards+0x84/0xb0 check_prev_add+0x5d2/0xc45 validate_chain+0xed3/0xf94 ? check_prev_add+0xc45/0xc45 ? mark_lock+0x11b/0x804 ? check_usage_forwards+0x1ca/0x1ca __lock_acquire+0x95f/0xa2f lock_acquire+0x1b4/0x1e8 ? kernfs_remove_by_name_ns+0x59/0x72 __kernfs_remove+0x237/0x40b ? kernfs_remove_by_name_ns+0x59/0x72 ? kernfs_next_descendant_post+0x7d/0x7d ? strlen+0x10/0x23 ? strcmp+0x22/0x44 kernfs_remove_by_name_ns+0x59/0x72 remove_files+0x61/0x96 sysfs_remove_group+0x81/0xa4 sysfs_remove_groups+0x3b/0x44 kobject_del+0x44/0x94 blk_mq_unregister_dev+0x83/0xdd blk_unregister_queue+0xa0/0x10b del_gendisk+0x259/0x3fa ? disk_events_poll_msecs_store+0x12b/0x12b ? check_flags+0x1ea/0x204 ? mark_held_locks+0x1f/0x7a null_del_dev+0x8b/0x1c3 [null_blk] null_exit+0x5c/0x95 [null_blk] __se_sys_delete_module+0x204/0x337 ? free_module+0x39f/0x39f ? blkcg_maybe_throttle_current+0x8a/0x718 ? rwlock_bug+0x62/0x62 ? __blkcg_punt_bio_submit+0xd0/0xd0 ? trace_hardirqs_on_thunk+0x1a/0x20 ? mark_held_locks+0x1f/0x7a ? do_syscall_64+0x4c/0x295 do_syscall_64+0xa7/0x295 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7fb696cdbe6b Code: 73 01 c3 48 8b 0d 1d 20 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 008 RSP: 002b:00007ffec9588788 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0 RAX: ffffffffffffffda RBX: 0000559e589137c0 RCX: 00007fb696cdbe6b RDX: 000000000000000a RSI: 0000000000000800 RDI: 0000559e58913828 RBP: 0000000000000000 R08: 00007ffec9587701 R09: 0000000000000000 R10: 00007fb696d4eae0 R11: 0000000000000206 R12: 00007ffec95889b0 R13: 00007ffec95896b3 R14: 0000559e58913260 R15: 0000559e589137c0 Cc: Christoph Hellwig <hch@infradead.org> Cc: Hannes Reinecke <hare@suse.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Mike Snitzer <snitzer@redhat.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: add helper for checking if queue is registeredMing Lei2019-08-271-1/+1
| | | | | | | | | | | | | | There are 4 users which check if queue is registered, so add one helper to check it. Cc: Christoph Hellwig <hch@infradead.org> Cc: Hannes Reinecke <hare@suse.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Mike Snitzer <snitzer@redhat.com> Cc: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: don't hold q->sysfs_lock in elevator_init_mqMing Lei2019-08-271-9/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | The original comment says: q->sysfs_lock must be held to provide mutual exclusion between elevator_switch() and here. Which is simply wrong. elevator_init_mq() is only called from blk_mq_init_allocated_queue, which is always called before the request queue is registered via blk_register_queue(), for dm-rq or normal rq based driver. However, queue's kobject is only exposed and added to sysfs in blk_register_queue(). So there isn't such race between elevator_switch() and elevator_init_mq(). So avoid to hold q->sysfs_lock in elevator_init_mq(). Cc: Christoph Hellwig <hch@infradead.org> Cc: Hannes Reinecke <hare@suse.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Mike Snitzer <snitzer@redhat.com> Cc: Bart Van Assche <bvanassche@acm.org> Cc: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: free sched's request pool in blk_cleanup_queueMing Lei2019-06-071-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In theory, IO scheduler belongs to request queue, and the request pool of sched tags belongs to the request queue too. However, the current tags allocation interfaces are re-used for both driver tags and sched tags, and driver tags is definitely host wide, and doesn't belong to any request queue, same with its request pool. So we need tagset instance for freeing request of sched tags. Meantime, blk_mq_free_tag_set() often follows blk_cleanup_queue() in case of non-BLK_MQ_F_TAG_SHARED, this way requires that request pool of sched tags to be freed before calling blk_mq_free_tag_set(). Commit 47cdee29ef9d94e ("block: move blk_exit_queue into __blk_release_queue") moves blk_exit_queue into __blk_release_queue for simplying the fast path in generic_make_request(), then causes oops during freeing requests of sched tags in __blk_release_queue(). Fix the above issue by move freeing request pool of sched tags into blk_cleanup_queue(), this way is safe becasue queue has been frozen and no any in-queue requests at that time. Freeing sched tags has to be kept in queue's release handler becasue there might be un-completed dispatch activity which might refer to sched tags. Cc: Bart Van Assche <bvanassche@acm.org> Cc: Christoph Hellwig <hch@lst.de> Fixes: 47cdee29ef9d94e485eb08f962c74943023a5271 ("block: move blk_exit_queue into __blk_release_queue") Tested-by: Yi Zhang <yi.zhang@redhat.com> Reported-by: kernel test robot <rong.a.chen@intel.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: add SPDX tags to block layer files missing licensing informationChristoph Hellwig2019-05-011-0/+1
| | | | | | | | | Various block layer files do not have any licensing information at all. Add SPDX tags for the default kernel GPLv2 license to those. Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: remove unused variable 'def'Hisao Tanabe2019-04-081-4/+2
| | | | | | | | | The 'def' local variable became unused after commit f382fb0bcef4 ("block: remove legacy IO schedulers"), let's remove it. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Hisao Tanabe <xtanabe@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: avoid setting none scheduler if it's already noneAleksei Zakharov2019-02-111-1/+4
| | | | | | | | There's no reason to freeze queue and remove scheduler if there's no scheduler already. Signed-off-by: Aleksei Zakharov <zakharov.a.g@yandex.ru> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: add queue_is_mq() helperJens Axboe2018-11-161-6/+5
| | | | | | | | | | | | | Various spots check for q->mq_ops being non-NULL, but provide a helper to do this instead. Where the ->mq_ops != NULL check is redundant, remove it. Since mq == rq-based now that legacy is gone, get rid of the queue_is_rq_based() and just use queue_is_mq() everywhere. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: clean up dead code that is now redundantColin Ian King2018-11-141-7/+0
| | | | | | | | | | | | | | The boolean next_sorted is set to false and is never changed, hence the code that checks if it is true is dead code and can now be removed. This dead code occurred from a previous commit that cleaned up the elevator and removed the setting of next_sorted to true. Detected by CoverityScan, CID#1475401 ("'Constant' variable guards dead code") Fixes: a1ce35fa4985 ("block: remove dead elevator code") Signed-off-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: get rid of MQ scheduler ops unionJens Axboe2018-11-071-13/+13
| | | | | | | | This is a remnant of when we had ops for both SQ and MQ schedulers. Now it's just MQ, so get rid of the union. Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: remove dead elevator codeJens Axboe2018-11-071-355/+22
| | | | | | | | | | | | | | | | | | | This removes a bunch of core and elevator related code. On the core front, we remove anything related to queue running, draining, initialization, plugging, and congestions. We also kill anything related to request allocation, merging, retrieval, and completion. Remove any checking for single queue IO schedulers, as they no longer exist. This means we can also delete a bunch of code related to request issue, adding, completion, etc - and all the SQ related ops and helpers. Also kill the load_default_modules(), as all that did was provide for a way to load the default single queue elevator. Tested-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: remove legacy IO schedulersJens Axboe2018-11-071-70/+0
| | | | | | | | | Retain the deadline documentation, as that carries over to mq-deadline as well. Tested-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* Merge tag 'v4.19-rc6' into for-4.20/blockJens Axboe2018-10-011-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge -rc6 in, for two reasons: 1) Resolve a trivial conflict in the blk-mq-tag.c documentation 2) A few important regression fixes went into upstream directly, so they aren't in the 4.20 branch. Signed-off-by: Jens Axboe <axboe@kernel.dk> * tag 'v4.19-rc6': (780 commits) Linux 4.19-rc6 MAINTAINERS: fix reference to moved drivers/{misc => auxdisplay}/panel.c cpufreq: qcom-kryo: Fix section annotations perf/core: Add sanity check to deal with pinned event failure xen/blkfront: correct purging of persistent grants Revert "xen/blkfront: When purging persistent grants, keep them in the buffer" selftests/powerpc: Fix Makefiles for headers_install change blk-mq: I/O and timer unplugs are inverted in blktrace dax: Fix deadlock in dax_lock_mapping_entry() x86/boot: Fix kexec booting failure in the SEV bit detection code bcache: add separate workqueue for journal_write to avoid deadlock drm/amd/display: Fix Edid emulation for linux drm/amd/display: Fix Vega10 lightup on S3 resume drm/amdgpu: Fix vce work queue was not cancelled when suspend Revert "drm/panel: Add device_link from panel device to DRM device" xen/blkfront: When purging persistent grants, keep them in the buffer clocksource/drivers/timer-atmel-pit: Properly handle error cases block: fix deadline elevator drain for zoned block devices ACPI / hotplug / PCI: Don't scan for non-hotplug bridges if slot is not bridge drm/syncobj: Don't leak fences when WAIT_FOR_SUBMIT is set ... Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * block: fix deadline elevator drain for zoned block devicesDamien Le Moal2018-09-271-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When the deadline scheduler is used with a zoned block device, writes to a zone will be dispatched one at a time. This causes the warning message: deadline: forced dispatching is broken (nr_sorted=X), please report this to be displayed when switching to another elevator with the legacy I/O path while write requests to a zone are being retained in the scheduler queue. Prevent this message from being displayed when executing elv_drain_elevator() for a zoned block device. __blk_drain_queue() will loop until all writes are dispatched and completed, resulting in the desired elevator queue drain without extensive modifications to the deadline code itself to handle forced-dispatch calls. Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Fixes: 8dc8146f9c92 ("deadline-iosched: Introduce zone locking support") Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | block: Schedule runtime resume earlierBart Van Assche2018-09-261-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Instead of scheduling runtime resume of a request queue after a request has been queued, schedule asynchronous resume during request allocation. The new pm_request_resume() calls occur after blk_queue_enter() has increased the q_usage_counter request queue member. This change is needed for a later patch that will make request allocation block while the queue status is not RPM_ACTIVE. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Jianchao Wang <jianchao.w.wang@oracle.com> Cc: Hannes Reinecke <hare@suse.com> Cc: Johannes Thumshirn <jthumshirn@suse.de> Cc: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | block: Split blk_pm_add_request() and blk_pm_put_request()Bart Van Assche2018-09-261-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Move the pm_request_resume() and pm_runtime_mark_last_busy() calls into two new functions and thereby separate legacy block layer code from code that works for both the legacy block layer and blk-mq. A later patch will add calls to the new functions in the blk-mq code. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Martin K. Petersen <martin.petersen@oracle.com> Cc: Jianchao Wang <jianchao.w.wang@oracle.com> Cc: Hannes Reinecke <hare@suse.com> Cc: Johannes Thumshirn <jthumshirn@suse.de> Cc: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | block: Move power management code into a new source fileBart Van Assche2018-09-261-21/+1
|/ | | | | | | | | | | | | | | | | | | | Move the code for runtime power management from blk-core.c into the new source file blk-pm.c. Move the corresponding declarations from <linux/blkdev.h> into <linux/blk-pm.h>. For CONFIG_PM=n, leave out the declarations of the functions that are not used in that mode. This patch not only reduces the number of #ifdefs in the block layer core code but also reduces the size of header file <linux/blkdev.h> and hence should help to reduce the build time of the Linux kernel if CONFIG_PM is not defined. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Jianchao Wang <jianchao.w.wang@oracle.com> Cc: Hannes Reinecke <hare@suse.com> Cc: Johannes Thumshirn <jthumshirn@suse.de> Cc: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: remove unnecessary condition checkChengguang Xu2018-08-281-2/+1
| | | | | | | | kmem_cache_destroy() can handle NULL pointer correctly, so there is no need to check e->icq_cache before calling kmem_cache_destroy(). Signed-off-by: Chengguang Xu <cgxu519@gmx.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-mq: init hctx sched after update ctx and hctx mappingJianchao Wang2018-08-211-8/+12
| | | | | | | | | | | | | | Currently, when update nr_hw_queues, IO scheduler's init_hctx will be invoked before the mapping between ctx and hctx is adapted correctly by blk_mq_map_swqueue. The IO scheduler init_hctx (kyber) may depend on this mapping and get wrong result and panic finally. A simply way to fix this is that switch the IO scheduler to 'none' before update the nr_hw_queues, and then switch it back after update nr_hw_queues. blk_mq_sched_init_/exit_hctx are removed due to nobody use them any more. Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: split the blk-mq case from elevator_initChristoph Hellwig2018-06-011-31/+46
| | | | | | | | | | There is almost no shared logic, which leads to a very confusing code flow. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Tested-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: move sysfs_lock into elevator_initChristoph Hellwig2018-06-011-5/+6
| | | | | | | | | | Both callers take just around so function call, so move it in. Also remove the now pointless blk_mq_sched_init wrapper. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Tested-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: remove the always unused name argument to elevator_initChristoph Hellwig2018-06-011-8/+2
| | | | | | | | Reported-by: Damien Le Moal <Damien.LeMoal@wdc.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Tested-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: unexport elevator_init/exitChristoph Hellwig2018-06-011-2/+0
| | | | | | | | | | | These are only used by the block core. Also move the declarations to block/blk.h. Reported-by: Damien Le Moal <Damien.LeMoal@wdc.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Tested-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: move initialization of elevator-related fields to blk_alloc_queue_nodeChristoph Hellwig2018-06-011-5/+0
| | | | | | | | | | No point in doing this in elevator_init. Signed-off-by: Christoph Hellwig <hch@lst.de> Reported-by: Damien Le Moal <Damien.LeMoal@wdc.com> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Tested-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: Document scheduler modification locking requirementsBart Van Assche2018-01-181-0/+8
| | | | | | | | This patch does not change any functionality. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: Unexport elv_register_queue() and elv_unregister_queue()Bart Van Assche2018-01-181-2/+0
| | | | | | | | | These two functions are only called from inside the block layer so unexport them. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-mq: quiesce queue during switching io sched and updating nr_requestsMing Lei2018-01-061-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | Dispatch may still be in-progress after queue is frozen, so we have to quiesce queue before switching IO scheduler and updating nr_requests. Also when switching io schedulers, blk_mq_run_hw_queue() may still be called somewhere(such as from nvme_reset_work()), and io scheduler's per-hctx data may not be setup yet, so cause oops even inside blk_mq_hctx_has_pending(), such as it can be run just between: ret = e->ops.mq.init_sched(q, e); AND ret = e->ops.mq.init_hctx(hctx, i) inside blk_mq_init_sched(). This reverts commit 7a148c2fcff8330(block: don't call blk_mq_quiesce_queue() after queue is frozen) basically, and makes sure blk_mq_hctx_has_pending won't be called if queue is quiesced. Reviewed-by: Christoph Hellwig <hch@lst.de> Fixes: 7a148c2fcff83309(block: don't call blk_mq_quiesce_queue() after queue is frozen) Reported-by: Yi Zhang <yi.zhang@redhat.com> Tested-by: Yi Zhang <yi.zhang@redhat.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* elevator: allow name aliasesJens Axboe2017-10-251-6/+17
| | | | | | | | | | Since we now lookup elevator types with the appropriate multiqueue capability, allow schedulers to register with an alias alongside the real name. This is in preparation for allowing 'mq-deadline' to register an alias of 'deadline' as well. Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* elevator: lookup mq vs non-mq elevatorsJens Axboe2017-10-251-23/+21
| | | | | | | | | | | | | | | If an IO scheduler is selected via elevator= and it doesn't match the driver in question wrt blk-mq support, then we fail to boot. The elevator= parameter is deprecated and only supported for non-mq devices. Augment the elevator lookup API so that we pass in if we're looking for an mq capable scheduler or not, so that we only ever return a valid type for the queue in question. Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=196695 Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: remove QUEUE_FLAG_STACKABLEChristoph Hellwig2017-10-051-1/+1
| | | | | | | | | We already have a queue_is_rq_based helper to check if a request_queue is request based, so we can remove the flag for it. Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: fix warning when I/O elevator is changed as request_queue is being ↵David Jeffery2017-08-281-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | removed There is a race between changing I/O elevator and request_queue removal which can trigger the warning in kobject_add_internal. A program can use sysfs to request a change of elevator at the same time another task is unregistering the request_queue the elevator would be attached to. The elevator's kobject will then attempt to be connected to the request_queue in the object tree when the request_queue has just been removed from sysfs. This triggers the warning in kobject_add_internal as the request_queue no longer has a sysfs directory: kobject_add_internal failed for iosched (error: -2 parent: queue) ------------[ cut here ]------------ WARNING: CPU: 3 PID: 14075 at lib/kobject.c:244 kobject_add_internal+0x103/0x2d0 To fix this warning, we can check the QUEUE_FLAG_REGISTERED flag when changing the elevator and use the request_queue's sysfs_lock to serialize between clearing the flag and the elevator testing the flag. Signed-off-by: David Jeffery <djeffery@redhat.com> Tested-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: Add fallthrough markers to switch statementsBart Van Assche2017-06-211-0/+1
| | | | | | | | | | This patch suppresses gcc 7 warnings about falling through in switch statements when building with W=1. From the gcc documentation: The -Wimplicit-fallthrough=3 warning is enabled by -Wextra. See also https://gcc.gnu.org/onlinedocs/gcc-7.1.0/gcc/Warning-Options.html. Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* elevator: remove redundant warnings on IO scheduler switchJens Axboe2017-05-101-4/+1
| | | | | | | | | | | | We warn twice for switching to a scheduler, if that switch fails. As we also report the failure in the return value to the sysfs write, remove the dmesg induced failures. Keep the failure print for warning to switch to the kconfig selected IO scheduler, as we can't report errors for that in any other way. Signed-off-by: Jens Axboe <axboe@fb.com>
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