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* block: nr_sects_write(): Disable preemption on seqcount writeAhmed S. Darwish2020-06-051-0/+2
| | | | | | | | | | | | | | | | | | For optimized block readers not holding a mutex, the "number of sectors" 64-bit value is protected from tearing on 32-bit architectures by a sequence counter. Disable preemption before entering that sequence counter's write side critical section. Otherwise, the read side can preempt the write side section and spin for the entire scheduler tick. If the reader belongs to a real-time scheduling class, it can spin forever and the kernel will livelock. Fixes: c83f6bf98dc1 ("block: add partition resize function to blkpg ioctl") Cc: <stable@vger.kernel.org> Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-throttle: remove blk_throtl_drainGuoqing Jiang2020-05-301-2/+0
| | | | | | | | After the commit 5addeae1bedc4 ("blk-cgroup: remove blkcg_drain_queue"), there is no caller of blk_throtl_drain, so let's remove it. Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: add a blk_account_io_merge_bio helperKonstantin Khlebnikov2020-05-271-1/+1
| | | | | | | | | | | | | | | Move the non-"new_io" branch of blk_account_io_start() into separate function. Fix merge accounting for discards (they were counted as write merges). The new blk_account_io_merge_bio() doesn't call update_io_ticks() unlike blk_account_io_start(), as there is no reason for that. [hch: rebased] Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: always use a percpu variable for disk statsChristoph Hellwig2020-05-271-1/+1
| | | | | | | | | percpu variables have a perfectly fine working stub implementation for UP kernels, so use that. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: move update_io_ticks to blk-core.cChristoph Hellwig2020-05-271-1/+0
| | | | | | | | All callers are in blk-core.c, so move update_io_ticks over. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: Remove unused flush_queue_delayed in struct blk_flush_queueBaolin Wang2020-05-191-1/+0
| | | | | | | | | | | | | | The flush_queue_delayed was introdued to hold queue if flush is running for non-queueable flush drive by commit 3ac0cc450870 ("hold queue if flush is running for non-queueable flush drive"), but the non mq parts of the flush code had been removed by commit 7e992f847a08 ("block: remove non mq parts from the flush code"), as well as removing the usage of the flush_queue_delayed flag. Thus remove the unused flush_queue_delayed flag. Signed-off-by: Baolin Wang <baolin.wang7@gmail.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: merge part_{inc,dev}_in_flight into their only callersChristoph Hellwig2020-05-191-4/+0
| | | | | | | | | part_inc_in_flight and part_dec_in_flight only have one caller each, and those callers are purely for bio based drivers. Merge each function into the only caller, and remove the superflous blk-mq checks. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: mark blk_account_io_completion staticChristoph Hellwig2020-05-191-1/+0
| | | | | Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* blk-mq: allow blk_mq_make_request to consume the q_usage_counter referenceChristoph Hellwig2020-05-191-11/+0
| | | | | | | | | | | | | | | | blk_mq_make_request currently needs to grab an q_usage_counter reference when allocating a request. This is because the block layer grabs one before calling blk_mq_make_request, but also releases it as soon as blk_mq_make_request returns. Remove the blk_queue_exit call after blk_mq_make_request returns, and instead let it consume the reference. This works perfectly fine for the block layer caller, just device mapper needs an extra reference as the old problem still persists there. Open code blk_queue_enter_live in device mapper, as there should be no other callers and this allows better documenting why we do a non-try get. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: Inline encryption support for blk-mqSatya Tangirala2020-05-141-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We must have some way of letting a storage device driver know what encryption context it should use for en/decrypting a request. However, it's the upper layers (like the filesystem/fscrypt) that know about and manages encryption contexts. As such, when the upper layer submits a bio to the block layer, and this bio eventually reaches a device driver with support for inline encryption, the device driver will need to have been told the encryption context for that bio. We want to communicate the encryption context from the upper layer to the storage device along with the bio, when the bio is submitted to the block layer. To do this, we add a struct bio_crypt_ctx to struct bio, which can represent an encryption context (note that we can't use the bi_private field in struct bio to do this because that field does not function to pass information across layers in the storage stack). We also introduce various functions to manipulate the bio_crypt_ctx and make the bio/request merging logic aware of the bio_crypt_ctx. We also make changes to blk-mq to make it handle bios with encryption contexts. blk-mq can merge many bios into the same request. These bios need to have contiguous data unit numbers (the necessary changes to blk-merge are also made to ensure this) - as such, it suffices to keep the data unit number of just the first bio, since that's all a storage driver needs to infer the data unit number to use for each data block in each bio in a request. blk-mq keeps track of the encryption context to be used for all the bios in a request with the request's rq_crypt_ctx. When the first bio is added to an empty request, blk-mq will program the encryption context of that bio into the request_queue's keyslot manager, and store the returned keyslot in the request's rq_crypt_ctx. All the functions to operate on encryption contexts are in blk-crypto.c. Upper layers only need to call bio_crypt_set_ctx with the encryption key, algorithm and data_unit_num; they don't have to worry about getting a keyslot for each encryption context, as blk-mq/blk-crypto handles that. Blk-crypto also makes it possible for request-based layered devices like dm-rq to make use of inline encryption hardware by cloning the rq_crypt_ctx and programming a keyslot in the new request_queue when necessary. Note that any user of the block layer can submit bios with an encryption context, such as filesystems, device-mapper targets, etc. Signed-off-by: Satya Tangirala <satyat@google.com> Reviewed-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: rename __bio_add_pc_page to bio_add_hw_pageChristoph Hellwig2020-05-131-2/+2
| | | | | | | | | | | | | | | | Rename __bio_add_pc_page() to bio_add_hw_page() and explicitly pass in a max_sectors argument. This max_sectors argument can be used to specify constraints from the hardware. Signed-off-by: Christoph Hellwig <hch@lst.de> [ jth: rebased and made public for blk-map.c ] Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Daniel Wagner <dwagner@suse.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: don't hold part0's refcount in IO pathMing Lei2020-05-131-7/+6
| | | | | | | | | | | | gendisk can't be gone when there is IO activity, so not hold part0's refcount in IO path. Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Christoph Hellwig <hch@infradead.org> Cc: Yufen Yu <yuyufen@huawei.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Hou Tao <houtao1@huawei.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: remove create_io_contextChristoph Hellwig2020-04-251-20/+0
| | | | | | | | create_io_context just has a single caller, which also happens to not even use the return value. Just open code it there. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: remove hd_struct_killChristoph Hellwig2020-04-201-5/+0
| | | | | | | | The function has a single caller, so just open code it. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: cleanup hd_struct freeingChristoph Hellwig2020-04-201-9/+1
| | | | | | | | | Move hd_ref_init out of line as there it isn't anywhere near a fast path, and rename the rcu ref freeing callbacks to be more descriptive. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: pass a hd_struct to delete_partitionChristoph Hellwig2020-04-201-1/+1
| | | | | | | | | All callers have the hd_struct at hand, so pass it instead of performing another lookup. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: refactor blkpg_ioctlChristoph Hellwig2020-04-201-3/+5
| | | | | | | | | Split each sub-command out into a separate helper, and move those helpers to block/partitions/core.c instead of having a lot of partition manipulation logic open coded in block/ioctl.c. Signed-off-by: Christoph Hellwig <hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: move bio_map_* to blk-map.cChristoph Hellwig2020-03-271-0/+4
| | | | | | | | | The bio_map_* helpers are just the low-level helpers for the blk_rq_map_* APIs. Move them together for better logical grouping, as no there isn't much overlap with other code in bio.c. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: simplify queue allocationChristoph Hellwig2020-03-271-0/+2
| | | | | | | | | | | | | Current make_request based drivers use either blk_alloc_queue_node or blk_alloc_queue to allocate a queue, and then set up the make_request_fn function pointer and a few parameters using the blk_queue_make_request helper. Simplify this by passing the make_request pointer to blk_alloc_queue, and while at it merge the _node variant into the main helper by always passing a node_id, and remove the superfluous gfp_mask parameter. A lower-level __blk_alloc_queue is kept for the blk-mq case. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: move the part_stat* helpers from genhd.h to a new headerChristoph Hellwig2020-03-251-0/+1
| | | | | | | | These macros are just used by a few files. Move them out of genhd.h, which is included everywhere into a new standalone header. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: move block layer internals out of include/linux/genhd.hChristoph Hellwig2020-03-251-0/+116
| | | | | | | None of this needs to be exposed to drivers. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: move sysfs methods shared by disks and partitions to genhd.cChristoph Hellwig2020-03-241-0/+11
| | | | | | | | | | Move the sysfs _show methods that are used both on the full disk and partition nodes to genhd.c instead of hiding them in the partitioning code. Also move the declaration for these methods to block/blk.h so that we don't expose them to drivers. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: remove unneeded argument from blk_alloc_flush_queueGuoqing Jiang2020-03-121-2/+2
| | | | | | | | | | | | Remove 'q' from arguments since it is not used anymore after commit 7e992f847a08e ("block: remove non mq parts from the flush code"). Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com> Reviewed-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: Fix a lockdep complaint triggered by request queue flushingBart Van Assche2019-12-201-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Avoid that running test nvme/012 from the blktests suite triggers the following false positive lockdep complaint: ============================================ WARNING: possible recursive locking detected 5.0.0-rc3-xfstests-00015-g1236f7d60242 #841 Not tainted -------------------------------------------- ksoftirqd/1/16 is trying to acquire lock: 000000000282032e (&(&fq->mq_flush_lock)->rlock){..-.}, at: flush_end_io+0x4e/0x1d0 but task is already holding lock: 00000000cbadcbc2 (&(&fq->mq_flush_lock)->rlock){..-.}, at: flush_end_io+0x4e/0x1d0 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&(&fq->mq_flush_lock)->rlock); lock(&(&fq->mq_flush_lock)->rlock); *** DEADLOCK *** May be due to missing lock nesting notation 1 lock held by ksoftirqd/1/16: #0: 00000000cbadcbc2 (&(&fq->mq_flush_lock)->rlock){..-.}, at: flush_end_io+0x4e/0x1d0 stack backtrace: CPU: 1 PID: 16 Comm: ksoftirqd/1 Not tainted 5.0.0-rc3-xfstests-00015-g1236f7d60242 #841 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: dump_stack+0x67/0x90 __lock_acquire.cold.45+0x2b4/0x313 lock_acquire+0x98/0x160 _raw_spin_lock_irqsave+0x3b/0x80 flush_end_io+0x4e/0x1d0 blk_mq_complete_request+0x76/0x110 nvmet_req_complete+0x15/0x110 [nvmet] nvmet_bio_done+0x27/0x50 [nvmet] blk_update_request+0xd7/0x2d0 blk_mq_end_request+0x1a/0x100 blk_flush_complete_seq+0xe5/0x350 flush_end_io+0x12f/0x1d0 blk_done_softirq+0x9f/0xd0 __do_softirq+0xca/0x440 run_ksoftirqd+0x24/0x50 smpboot_thread_fn+0x113/0x1e0 kthread+0x121/0x140 ret_from_fork+0x3a/0x50 Cc: Christoph Hellwig <hch@infradead.org> Cc: Ming Lei <ming.lei@redhat.com> Cc: Hannes Reinecke <hare@suse.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: fix memleak of bio integrity dataJustin Tee2019-12-051-0/+4
| | | | | | | | | | | | | | | | | | | | | | 7c20f11680a4 ("bio-integrity: stop abusing bi_end_io") moves bio_integrity_free from bio_uninit() to bio_integrity_verify_fn() and bio_endio(). This way looks wrong because bio may be freed without calling bio_endio(), for example, blk_rq_unprep_clone() is called from dm_mq_queue_rq() when the underlying queue of dm-mpath is busy. So memory leak of bio integrity data is caused by commit 7c20f11680a4. Fixes this issue by re-adding bio_integrity_free() to bio_uninit(). Fixes: 7c20f11680a4 ("bio-integrity: stop abusing bi_end_io") Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by Justin Tee <justin.tee@broadcom.com> Add commit log, and simplify/fix the original patch wroten by Justin. Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: account statistics for passthrough requestsLogan Gunthorpe2019-10-111-5/+2
| | | | | | | | | | | | | | | | | Presently, passthrough requests are not accounted for because blk_do_io_stat() expressly rejects them. Based on some digging in the history, this doesn't seem like a concious decision but one that evolved from the change from blk_fs_request() to blk_rq_is_passthrough(). To support this, call blk_account_io_start() in blk_execute_rq_nowait() and remove the passthrough check in blk_do_io_stat(). Link: https://lore.kernel.org/linux-block/20191010100526.GA27209@lst.de/ Signed-off-by: Logan Gunthorpe <logang@deltatee.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: fix null pointer dereference in blk_mq_rq_timed_out()Yufen Yu2019-09-271-0/+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>
* blk-mq: move lockdep_assert_held() into elevator_exitMing Lei2019-09-261-0/+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>
* block: Change elevator_init_mq() to always succeedDamien Le Moal2019-09-061-1/+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>
* block: split .sysfs_lock into two locksMing Lei2019-08-271-1/+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>
* block: mark blk_rq_bio_prep as inlineChristoph Hellwig2019-06-201-1/+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>
* block: simplify blk_recalc_rq_segmentsChristoph Hellwig2019-06-201-1/+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>
* block: remove the bi_phys_segments field in struct bioChristoph Hellwig2019-06-201-11/+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>
* block: free sched's request pool in blk_cleanup_queueMing Lei2019-06-071-1/+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>
* block: move blk_exit_queue into __blk_release_queueMing Lei2019-05-291-1/+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>
* block: pass page to xen_biovec_phys_mergeableMing Lei2019-04-011-1/+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>
* blk-mq: save queue mapping result into ctx directlyJianchao Wang2019-02-011-1/+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>
* block: sum requests in the plug structureJens Axboe2018-11-261-2/+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>
* block: Remove bio->bi_iocDamien Le Moal2018-11-201-16/+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>
* Merge tag 'v4.20-rc3' into for-4.21/blockJens Axboe2018-11-181-1/+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>
| * block: make sure discard bio is aligned with logical block sizeMing Lei2018-11-091-0/+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>
| * block: respect virtual boundary mask in bvecsJohannes Thumshirn2018-11-071-1/+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>
* | block: remove queue_lockdep_assert_heldChristoph Hellwig2018-11-151-13/+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>
* | block: use atomic bitops for ->queue_flagsChristoph Hellwig2018-11-151-56/+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>
* | block: remove deadline __deadline manipulation helpersChristoph Hellwig2018-11-151-35/+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>
* | block: remove req->timeout_listChristoph Hellwig2018-11-091-2/+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>
* | blk-mq: pass in request/bio flags to queue mappingJens Axboe2018-11-071-3/+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>
* | block: kill request slab cacheJens Axboe2018-11-071-1/+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>
* | block: remove request_list codeJens Axboe2018-11-071-3/+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>
* | block: kill legacy parts of timeout handlingJens Axboe2018-11-071-1/+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>