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2019-09-27block: fix null pointer dereference in blk_mq_rq_timed_out()Yufen Yu1-0/+7
We got a null pointer deference BUG_ON in blk_mq_rq_timed_out() as following: [ 108.825472] BUG: kernel NULL pointer dereference, address: 0000000000000040 [ 108.827059] PGD 0 P4D 0 [ 108.827313] Oops: 0000 [#1] SMP PTI [ 108.827657] CPU: 6 PID: 198 Comm: kworker/6:1H Not tainted 5.3.0-rc8+ #431 [ 108.829503] Workqueue: kblockd blk_mq_timeout_work [ 108.829913] RIP: 0010:blk_mq_check_expired+0x258/0x330 [ 108.838191] Call Trace: [ 108.838406] bt_iter+0x74/0x80 [ 108.838665] blk_mq_queue_tag_busy_iter+0x204/0x450 [ 108.839074] ? __switch_to_asm+0x34/0x70 [ 108.839405] ? blk_mq_stop_hw_queue+0x40/0x40 [ 108.839823] ? blk_mq_stop_hw_queue+0x40/0x40 [ 108.840273] ? syscall_return_via_sysret+0xf/0x7f [ 108.840732] blk_mq_timeout_work+0x74/0x200 [ 108.841151] process_one_work+0x297/0x680 [ 108.841550] worker_thread+0x29c/0x6f0 [ 108.841926] ? rescuer_thread+0x580/0x580 [ 108.842344] kthread+0x16a/0x1a0 [ 108.842666] ? kthread_flush_work+0x170/0x170 [ 108.843100] ret_from_fork+0x35/0x40 The bug is caused by the race between timeout handle and completion for flush request. When timeout handle function blk_mq_rq_timed_out() try to read 'req->q->mq_ops', the 'req' have completed and reinitiated by next flush request, which would call blk_rq_init() to clear 'req' as 0. After commit 12f5b93145 ("blk-mq: Remove generation seqeunce"), normal requests lifetime are protected by refcount. Until 'rq->ref' drop to zero, the request can really be free. Thus, these requests cannot been reused before timeout handle finish. However, flush request has defined .end_io and rq->end_io() is still called even if 'rq->ref' doesn't drop to zero. After that, the 'flush_rq' can be reused by the next flush request handle, resulting in null pointer deference BUG ON. We fix this problem by covering flush request with 'rq->ref'. If the refcount is not zero, flush_end_io() return and wait the last holder recall it. To record the request status, we add a new entry 'rq_status', which will be used in flush_end_io(). Cc: Christoph Hellwig <hch@infradead.org> Cc: Keith Busch <keith.busch@intel.com> Cc: Bart Van Assche <bvanassche@acm.org> Cc: stable@vger.kernel.org # v4.18+ Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Bob Liu <bob.liu@oracle.com> Signed-off-by: Yufen Yu <yuyufen@huawei.com> ------- v2: - move rq_status from struct request to struct blk_flush_queue v3: - remove unnecessary '{}' pair. v4: - let spinlock to protect 'fq->rq_status' v5: - move rq_status after flush_running_idx member of struct blk_flush_queue Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-09-26blk-mq: move lockdep_assert_held() into elevator_exitMing Lei1-0/+2
Commit c48dac137a62 ("block: don't hold q->sysfs_lock in elevator_init_mq") removes q->sysfs_lock from elevator_init_mq(), but forgot to deal with lockdep_assert_held() called in blk_mq_sched_free_requests() which is run in failure path of elevator_init_mq(). blk_mq_sched_free_requests() is called in the following 3 functions: elevator_init_mq() elevator_exit() blk_cleanup_queue() In blk_cleanup_queue(), blk_mq_sched_free_requests() is followed exactly by 'mutex_lock(&q->sysfs_lock)'. So moving the lockdep_assert_held() from blk_mq_sched_free_requests() into elevator_exit() for fixing the report by syzbot. Reported-by: syzbot+da3b7677bb913dc1b737@syzkaller.appspotmail.com Fixed: c48dac137a62 ("block: don't hold q->sysfs_lock in elevator_init_mq") Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-09-05block: Change elevator_init_mq() to always succeedDamien Le Moal1-1/+1
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>
2019-08-27block: split .sysfs_lock into two locksMing Lei1-1/+1
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>
2019-06-20block: mark blk_rq_bio_prep as inlineChristoph Hellwig1-1/+12
This function just has a few trivial assignments, has two callers with one of them being in the fastpath. Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-20block: simplify blk_recalc_rq_segmentsChristoph Hellwig1-1/+1
Return the segement and let the callers assign them, which makes the code a littler more obvious. Also pass the request instead of q plus bio chain, allowing for the use of rq_for_each_bvec. Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-20block: remove the bi_phys_segments field in struct bioChristoph Hellwig1-11/+12
We only need the number of segments in the blk-mq submission path. Remove the field from struct bio, and return it from a variant of blk_queue_split instead of that it can passed as an argument to those functions that need the value. This also means we stop recounting segments except for cloning and partial segments. To keep the number of arguments in this how path down remove pointless struct request_queue arguments from any of the functions that had it and grew a nr_segs argument. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-06block: free sched's request pool in blk_cleanup_queueMing Lei1-1/+9
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>
2019-05-29block: move blk_exit_queue into __blk_release_queueMing Lei1-1/+0
Commit 498f6650aec8 ("block: Fix a race between the cgroup code and request queue initialization") moves what blk_exit_queue does into blk_cleanup_queue() for fixing issue caused by changing back queue lock. However, after legacy request IO path is killed, driver queue lock won't be used at all, and there isn't story for changing back queue lock. Then the issue addressed by Commit 498f6650aec8 doesn't exist any more. So move move blk_exit_queue into __blk_release_queue. This patch basically reverts the following two commits: 498f6650aec8 block: Fix a race between the cgroup code and request queue initialization 24ecc3585348 block: Ensure that a request queue is dissociated from the cgroup controller Cc: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-04-01block: pass page to xen_biovec_phys_mergeableMing Lei1-1/+1
xen_biovec_phys_mergeable() only needs .bv_page of the 2nd bio bvec for checking if the two bvecs can be merged, so pass page to xen_biovec_phys_mergeable() directly. No function change. Cc: ris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Juergen Gross <jgross@suse.com> Cc: xen-devel@lists.xenproject.org Cc: Omar Sandoval <osandov@fb.com> Cc: Christoph Hellwig <hch@lst.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-01blk-mq: save queue mapping result into ctx directlyJianchao Wang1-1/+1
Currently, the queue mapping result is saved in a two-dimensional array. In the hot path, to get a hctx, we need do following: q->queue_hw_ctx[q->tag_set->map[type].mq_map[cpu]] This isn't very efficient. We could save the queue mapping result into ctx directly with different hctx type, like, ctx->hctxs[type] Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-26block: sum requests in the plug structureJens Axboe1-2/+0
This isn't exactly the same as the previous count, as it includes requests for all devices. But that really doesn't matter, if we have more than the threshold (16) queued up, flush it. It's not worth it to have an expensive list loop for this. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-19block: Remove bio->bi_iocDamien Le Moal1-16/+0
bio->bi_ioc is never set so always NULL. Remove references to it in bio_disassociate_task() and in rq_ioc() and delete this field from struct bio. With this change, rq_ioc() always returns current->io_context without the need for a bio argument. Further simplify the code and make it more readable by also removing this helper, which also allows to simplify blk_mq_sched_assign_ioc() by removing its bio argument. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Adam Manzanares <adam.manzanares@wdc.com> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-18Merge tag 'v4.20-rc3' into for-4.21/blockJens Axboe1-1/+11
Merge in -rc3 to resolve a few conflicts, but also to get a few important fixes that have gone into mainline since the block 4.21 branch was forked off (most notably the SCSI queue issue, which is both a conflict AND needed fix). Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-15block: remove queue_lockdep_assert_heldChristoph Hellwig1-13/+0
The only remaining user unconditionally drops and reacquires the lock, which means we really don't need any additional (conditional) annotation. Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-15block: use atomic bitops for ->queue_flagsChristoph Hellwig1-56/+0
->queue_flags is generally not set or cleared in the fast path, and also generally set or cleared one flag at a time. Make use of the normal atomic bitops for it so that we don't need to take the queue_lock, which is otherwise mostly unused in the core block layer now. Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-15block: remove deadline __deadline manipulation helpersChristoph Hellwig1-35/+0
No users left since the removal of the legacy request interface, we can remove all the magic bit stealing now and make it a normal field. But use WRITE_ONCE/READ_ONCE on the new deadline field, given that we don't seem to have any mechanism to guarantee a new value actually gets seen by other threads. Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-09block: remove req->timeout_listChristoph Hellwig1-2/+0
Unused now that the legacy request path is gone. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-09block: make sure discard bio is aligned with logical block sizeMing Lei1-0/+10
Obviously the created discard bio has to be aligned with logical block size. This patch introduces the helper of bio_allowed_max_sectors() for this purpose. Cc: stable@vger.kernel.org Cc: Mike Snitzer <snitzer@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Xiao Ni <xni@redhat.com> Cc: Mariusz Dabrowski <mariusz.dabrowski@intel.com> Fixes: 744889b7cbb56a6 ("block: don't deal with discard limit in blkdev_issue_discard()") Fixes: a22c4d7e34402cc ("block: re-add discard_granularity and alignment checks") Reported-by: Rui Salvaterra <rsalvaterra@gmail.com> Tested-by: Rui Salvaterra <rsalvaterra@gmail.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-07blk-mq: pass in request/bio flags to queue mappingJens Axboe1-3/+3
Prep patch for being able to place request based not just on CPU location, but also on the type of request. Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-07block: kill request slab cacheJens Axboe1-1/+0
Reviewed-by: Hannes Reinecke <hare@suse.com> Tested-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-07block: remove request_list codeJens Axboe1-3/+0
It's now dead code, nobody uses it. Reviewed-by: Hannes Reinecke <hare@suse.com> Tested-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-07block: kill legacy parts of timeout handlingJens Axboe1-1/+0
The only user of legacy timing now is BSG, which is invoked from the mq timeout handler. Kill the legacy code, and rename the q->rq_timed_out_fn to q->bsg_job_timeout_fn. Reviewed-by: Hannes Reinecke <hare@suse.com> Tested-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-07block: remove dead elevator codeJens Axboe1-51/+0
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>
2018-11-07block: remove non mq parts from the flush codeJens Axboe1-3/+1
Reviewed-by: Hannes Reinecke <hare@suse.com> Tested-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-07block: respect virtual boundary mask in bvecsJohannes Thumshirn1-1/+1
With drivers that are settting a virtual boundary constrain, we are seeing a lot of bio splitting and smaller I/Os being submitted to the driver. This happens because the bio gap detection code does not account cases where PAGE_SIZE - 1 is bigger than queue_virt_boundary() and thus will split the bio unnecessarily. Cc: Jan Kara <jack@suse.cz> Cc: Bart Van Assche <bvanassche@acm.org> Cc: Ming Lei <ming.lei@redhat.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de> Acked-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-25block: Introduce blk_revalidate_disk_zones()Damien Le Moal1-0/+6
Drivers exposing zoned block devices have to initialize and maintain correctness (i.e. revalidate) of the device zone bitmaps attached to the device request queue (seq_zones_bitmap and seq_zones_wlock). To simplify coding this, introduce a generic helper function blk_revalidate_disk_zones() suitable for most (and likely all) cases. This new function always update the seq_zones_bitmap and seq_zones_wlock bitmaps as well as the queue nr_zones field when called for a disk using a request based queue. For a disk using a BIO based queue, only the number of zones is updated since these queues do not have schedulers and so do not need the zone bitmaps. With this change, the zone bitmap initialization code in sd_zbc.c can be replaced with a call to this function in sd_zbc_read_zones(), which is called from the disk revalidate block operation method. A call to blk_revalidate_disk_zones() is also added to the null_blk driver for devices created with the zoned mode enabled. Finally, to ensure that zoned devices created with dm-linear or dm-flakey expose the correct number of zones through sysfs, a call to blk_revalidate_disk_zones() is added to dm_table_set_restrictions(). The zone bitmaps allocated and initialized with blk_revalidate_disk_zones() are freed automatically from __blk_release_queue() using the block internal function blk_queue_free_zone_bitmaps(). Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-25block: Improve zone reset executionDamien Le Moal1-0/+2
There is no need to synchronously execute all REQ_OP_ZONE_RESET BIOs necessary to reset a range of zones. Similarly to what is done for discard BIOs in blk-lib.c, all zone reset BIOs can be chained and executed asynchronously and a synchronous call done only for the last BIO of the chain. Modify blkdev_reset_zones() to operate similarly to blkdev_issue_discard() using the next_bio() helper for chaining BIOs. To avoid code duplication of that function in blk_zoned.c, rename next_bio() into blk_next_bio() and declare it as a block internal function in blk.h. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-13blk-mq: change gfp flags to GFP_NOIO in blk_mq_realloc_hw_ctxsJianchao Wang1-1/+1
blk_mq_realloc_hw_ctxs could be invoked during update hw queues. At the momemt, IO is blocked. Change the gfp flags from GFP_KERNEL to GFP_NOIO to avoid forever hang during memory allocation in blk_mq_realloc_hw_ctxs. Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-09-26block: remove ARCH_BIOVEC_PHYS_MERGEABLEChristoph Hellwig1-5/+2
Take the Xen check into the core code instead of delegating it to the architectures. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-09-24block: remove bvec_to_physChristoph Hellwig1-2/+2
We only use it in biovec_phys_mergeable and a m68k paravirt driver, so just opencode it there. Also remove the pointless unsigned long cast for the offset in the opencoded instances. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-09-24block: merge BIOVEC_SEG_BOUNDARY into biovec_phys_mergeableChristoph Hellwig1-3/+9
These two checks should always be performed together, so merge them into a single helper. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-09-24block: simplify BIOVEC_PHYS_MERGEABLEChristoph Hellwig1-0/+14
Turn the macro into an inline, move it to blk.h and simplify the arch hooks a bit. Also rename the function to biovec_phys_mergeable as there is no need to shout. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-09-24block: move req_gap_back_merge to blk.hChristoph Hellwig1-0/+19
No need to expose these helpers outside the block layer. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-09-24block: move integrity_req_gap_{back,front}_merge to blk.hChristoph Hellwig1-2/+33
No need to expose these to drivers. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-21blk-mq: init hctx sched after update ctx and hctx mappingJianchao Wang1-0/+2
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>
2018-08-16block: change return type to boolChengguang Xu1-1/+1
Because blk_do_io_stat() only does a judgement about the request contributes to IO statistics, it better changes return type to bool. Signed-off-by: Chengguang Xu <cgxu519@gmx.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-08-09block: Introduce blk_exit_queue()Bart Van Assche1-0/+1
This patch does not change any functionality. Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Cc: Christoph Hellwig <hch@lst.de> Cc: Ming Lei <ming.lei@redhat.com> Cc: Omar Sandoval <osandov@fb.com> Cc: Alexandru Moise <00moses.alexander00@gmail.com> Cc: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: <stable@vger.kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-07-09block: introduce blk-iolatency io controllerJosef Bacik1-0/+6
Current IO controllers for the block layer are less than ideal for our use case. The io.max controller is great at hard limiting, but it is not work conserving. This patch introduces io.latency. You provide a latency target for your group and we monitor the io in short windows to make sure we are not exceeding those latency targets. This makes use of the rq-qos infrastructure and works much like the wbt stuff. There are a few differences from wbt - It's bio based, so the latency covers the whole block layer in addition to the actual io. - We will throttle all IO types that comes in here if we need to. - We use the mean latency over the 100ms window. This is because writes can be particularly fast, which could give us a false sense of the impact of other workloads on our protected workload. - By default there's no throttling, we set the queue_depth to INT_MAX so that we can have as many outstanding bio's as we're allowed to. Only at throttle time do we pay attention to the actual queue depth. - We backcharge cgroups for root cg issued IO and induce artificial delays in order to deal with cases like metadata only or swap heavy workloads. In testing this has worked out relatively well. Protected workloads will throttle noisy workloads down to 1 io at time if they are doing normal IO on their own, or induce up to a 1 second delay per syscall if they are doing a lot of root issued IO (metadata/swap IO). Our testing has revolved mostly around our production web servers where we have hhvm (the web server application) in a protected group and everything else in another group. We see slightly higher requests per second (RPS) on the test tier vs the control tier, and much more stable RPS across all machines in the test tier vs the control tier. Another test we run is a slow memory allocator in the unprotected group. Before this would eventually push us into swap and cause the whole box to die and not recover at all. With these patches we see slight RPS drops (usually 10-15%) before the memory consumer is properly killed and things recover within seconds. Signed-off-by: Josef Bacik <jbacik@fb.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-06-01block: split the blk-mq case from elevator_initChristoph Hellwig1-0/+1
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>
2018-06-01block: remove the always unused name argument to elevator_initChristoph Hellwig1-1/+1
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>
2018-06-01block: unexport elevator_init/exitChristoph Hellwig1-0/+2
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>
2018-05-09block: consolidate struct request timestamp fieldsOmar Sandoval1-1/+1
Currently, struct request has four timestamp fields: - A start time, set at get_request time, in jiffies, used for iostats - An I/O start time, set at start_request time, in ktime nanoseconds, used for blk-stats (i.e., wbt, kyber, hybrid polling) - Another start time and another I/O start time, used for cfq and bfq These can all be consolidated into one start time and one I/O start time, both in ktime nanoseconds, shaving off up to 16 bytes from struct request depending on the kernel config. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-03-08block: Move the queue_flag_*() functions from a public into a private header fileBart Van Assche1-0/+69
This patch helps to avoid that new code gets introduced in block drivers that manipulates queue flags without holding the queue lock when that lock should be held. Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.de> Cc: Ming Lei <ming.lei@redhat.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-01-29Merge branch 'for-4.16/block' of git://git.kernel.dk/linux-blockLinus Torvalds1-19/+27
Pull block updates from Jens Axboe: "This is the main pull request for block IO related changes for the 4.16 kernel. Nothing major in this pull request, but a good amount of improvements and fixes all over the map. This contains: - BFQ improvements, fixes, and cleanups from Angelo, Chiara, and Paolo. - Support for SMR zones for deadline and mq-deadline from Damien and Christoph. - Set of fixes for bcache by way of Michael Lyle, including fixes from himself, Kent, Rui, Tang, and Coly. - Series from Matias for lightnvm with fixes from Hans Holmberg, Javier, and Matias. Mostly centered around pblk, and the removing rrpc 1.2 in preparation for supporting 2.0. - A couple of NVMe pull requests from Christoph. Nothing major in here, just fixes and cleanups, and support for command tracing from Johannes. - Support for blk-throttle for tracking reads and writes separately. From Joseph Qi. A few cleanups/fixes also for blk-throttle from Weiping. - Series from Mike Snitzer that enables dm to register its queue more logically, something that's alwways been problematic on dm since it's a stacked device. - Series from Ming cleaning up some of the bio accessor use, in preparation for supporting multipage bvecs. - Various fixes from Ming closing up holes around queue mapping and quiescing. - BSD partition fix from Richard Narron, fixing a problem where we can't mount newer (10/11) FreeBSD partitions. - Series from Tejun reworking blk-mq timeout handling. The previous scheme relied on atomic bits, but it had races where we would think a request had timed out if it to reused at the wrong time. - null_blk now supports faking timeouts, to enable us to better exercise and test that functionality separately. From me. - Kill the separate atomic poll bit in the request struct. After this, we don't use the atomic bits on blk-mq anymore at all. From me. - sgl_alloc/free helpers from Bart. - Heavily contended tag case scalability improvement from me. - Various little fixes and cleanups from Arnd, Bart, Corentin, Douglas, Eryu, Goldwyn, and myself" * 'for-4.16/block' of git://git.kernel.dk/linux-block: (186 commits) block: remove smart1,2.h nvme: add tracepoint for nvme_complete_rq nvme: add tracepoint for nvme_setup_cmd nvme-pci: introduce RECONNECTING state to mark initializing procedure nvme-rdma: remove redundant boolean for inline_data nvme: don't free uuid pointer before printing it nvme-pci: Suspend queues after deleting them bsg: use pr_debug instead of hand crafted macros blk-mq-debugfs: don't allow write on attributes with seq_operations set nvme-pci: Fix queue double allocations block: Set BIO_TRACE_COMPLETION on new bio during split blk-throttle: use queue_is_rq_based block: Remove kblockd_schedule_delayed_work{,_on}() blk-mq: Avoid that blk_mq_delay_run_hw_queue() introduces unintended delays blk-mq: Rename blk_mq_request_direct_issue() into blk_mq_request_issue_directly() lib/scatterlist: Fix chaining support in sgl_alloc_order() blk-throttle: track read and write request individually block: add bdev_read_only() checks to common helpers block: fail op_is_write() requests to read-only partitions blk-throttle: export io_serviced_recursive, io_service_bytes_recursive ...
2018-01-18block: Unexport elv_register_queue() and elv_unregister_queue()Bart Van Assche1-0/+3
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>
2018-01-10block: convert REQ_ATOM_COMPLETE to stealing rq->__deadline bitJens Axboe1-10/+9
We only have one atomic flag left. Instead of using an entire unsigned long for that, steal the bottom bit of the deadline field that we already reserved. Remove ->atomic_flags, since it's now unused. Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-01-10block: add accessors for setting/querying request deadlineJens Axboe1-0/+15
We reduce the resolution of request expiry, but since we're already using jiffies for this where resolution depends on the kernel configuration and since the timeout resolution is coarse anyway, that should be fine. Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-01-10block: remove REQ_ATOM_POLL_SLEPTJens Axboe1-2/+0
We don't need this to be an atomic flag, it can be a regular flag. We either end up on the same CPU for the polling, in which case the state is sane, or we did the sleep which would imply the needed barrier to ensure we see the right state. Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-01-09blk-mq: remove REQ_ATOM_STARTEDTejun Heo1-1/+0
After the recent updates to use generation number and state based synchronization, we can easily replace REQ_ATOM_STARTED usages by adding an extra state to distinguish completed but not yet freed state. Add MQ_RQ_COMPLETE and replace REQ_ATOM_STARTED usages with blk_mq_rq_state() tests. REQ_ATOM_STARTED no longer has any users left and is removed. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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