#
90110e04 |
| 13-Apr-2023 |
Christoph Hellwig <hch@lst.de> |
blk-mq: include <linux/blk-mq.h> in block/blk-mq.h
block/blk-mq.h needs various definitions from <linux/blk-mq.h>, include it there instead of relying on the source files to include both.
Signed-of
blk-mq: include <linux/blk-mq.h> in block/blk-mq.h
block/blk-mq.h needs various definitions from <linux/blk-mq.h>, include it there instead of relying on the source files to include both.
Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Link: https://lore.kernel.org/r/20230413064057.707578-4-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
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#
bebe84eb |
| 13-Apr-2023 |
Christoph Hellwig <hch@lst.de> |
blk-mq: remove blk-mq-tag.h
blk-mq-tag.h is always included by blk-mq.h, and causes recursive inclusion hell with further changes. Just merge it into blk-mq.h instead.
Signed-off-by: Christoph Hel
blk-mq: remove blk-mq-tag.h
blk-mq-tag.h is always included by blk-mq.h, and causes recursive inclusion hell with further changes. Just merge it into blk-mq.h instead.
Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Link: https://lore.kernel.org/r/20230413064057.707578-3-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
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5f622417 |
| 08-Feb-2023 |
Thomas Weißschuh <linux@weissschuh.net> |
block: make kobj_type structures constant
Since commit ee6d3dd4ed48 ("driver core: make kobj_type constant.") the driver core allows the usage of const struct kobj_type.
Take advantage of this to c
block: make kobj_type structures constant
Since commit ee6d3dd4ed48 ("driver core: make kobj_type constant.") the driver core allows the usage of const struct kobj_type.
Take advantage of this to constify the structure definitions to prevent modification at runtime.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Link: https://lore.kernel.org/r/20230208-kobj_type-block-v1-1-0b3eafd7d983@weissschuh.net Signed-off-by: Jens Axboe <axboe@kernel.dk>
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#
b3678103 |
| 28-Jan-2023 |
Zhong Jinghua <zhongjinghua@huawei.com> |
blk-mq: cleanup unused methods: blk_mq_hw_sysfs_store
We found that the blk_mq_hw_sysfs_store interface has no place to use. The object default_hw_ctx_attrs using blk_mq_hw_sysfs_ops only uses the s
blk-mq: cleanup unused methods: blk_mq_hw_sysfs_store
We found that the blk_mq_hw_sysfs_store interface has no place to use. The object default_hw_ctx_attrs using blk_mq_hw_sysfs_ops only uses the show method and does not use the store method.
Since this patch: 4a46f05ebf99 ("blk-mq: move hctx and ctx counters from sysfs to debugfs") moved the store method to debugfs, the store method is not used anymore.
So let me do some tiny work to clean up unused code.
Signed-off-by: Zhong Jinghua <zhongjinghua@huawei.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20230128030419.2780298-1-zhongjinghua@huawei.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
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#
4b7a21c5 |
| 17-Nov-2022 |
Ye Bin <yebin10@huawei.com> |
blk-mq: fix possible memleak when register 'hctx' failed
There's issue as follows when do fault injection test: unreferenced object 0xffff888132a9f400 (size 512): comm "insmod", pid 308021, jiffie
blk-mq: fix possible memleak when register 'hctx' failed
There's issue as follows when do fault injection test: unreferenced object 0xffff888132a9f400 (size 512): comm "insmod", pid 308021, jiffies 4324277909 (age 509.733s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 08 f4 a9 32 81 88 ff ff ...........2.... 08 f4 a9 32 81 88 ff ff 00 00 00 00 00 00 00 00 ...2............ backtrace: [<00000000e8952bb4>] kmalloc_node_trace+0x22/0xa0 [<00000000f9980e0f>] blk_mq_alloc_and_init_hctx+0x3f1/0x7e0 [<000000002e719efa>] blk_mq_realloc_hw_ctxs+0x1e6/0x230 [<000000004f1fda40>] blk_mq_init_allocated_queue+0x27e/0x910 [<00000000287123ec>] __blk_mq_alloc_disk+0x67/0xf0 [<00000000a2a34657>] 0xffffffffa2ad310f [<00000000b173f718>] 0xffffffffa2af824a [<0000000095a1dabb>] do_one_initcall+0x87/0x2a0 [<00000000f32fdf93>] do_init_module+0xdf/0x320 [<00000000cbe8541e>] load_module+0x3006/0x3390 [<0000000069ed1bdb>] __do_sys_finit_module+0x113/0x1b0 [<00000000a1a29ae8>] do_syscall_64+0x35/0x80 [<000000009cd878b0>] entry_SYSCALL_64_after_hwframe+0x46/0xb0
Fault injection context as follows: kobject_add blk_mq_register_hctx blk_mq_sysfs_register blk_register_queue device_add_disk null_add_dev.part.0 [null_blk]
As 'blk_mq_register_hctx' may already add some objects when failed halfway, but there isn't do fallback, caller don't know which objects add failed. To solve above issue just do fallback when add objects failed halfway in 'blk_mq_register_hctx'.
Signed-off-by: Ye Bin <yebin10@huawei.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20221117022940.873959-1-yebin@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
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#
8682b92e |
| 28-Jun-2022 |
Christoph Hellwig <hch@lst.de> |
blk-mq: cleanup disk sysfs registration
Pass a gendisk to the sysfs register/unregister functions and give them descriptive names. Also move the unregistration helper next to the one doing the regi
blk-mq: cleanup disk sysfs registration
Pass a gendisk to the sysfs register/unregister functions and give them descriptive names. Also move the unregistration helper next to the one doing the registration.
Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20220628171850.1313069-7-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
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#
eaa870f9 |
| 28-Jun-2022 |
Christoph Hellwig <hch@lst.de> |
blk-mq: rename blk_mq_sysfs_{,un}register
Add a _hctx postfix to better describe what the functions do, match the debugfs equivalents and release the old names for functions that should be using the
blk-mq: rename blk_mq_sysfs_{,un}register
Add a _hctx postfix to better describe what the functions do, match the debugfs equivalents and release the old names for functions that should be using them.
Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20220628171850.1313069-6-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
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#
81f0c2ef |
| 28-Jun-2022 |
Christoph Hellwig <hch@lst.de> |
block: remove the extra gendisk reference in __blk_mq_register_dev
kobject_add already grabs a reference to the parent, no need to have another one.
Signed-off-by: Christoph Hellwig <hch@lst.de> Re
block: remove the extra gendisk reference in __blk_mq_register_dev
kobject_add already grabs a reference to the parent, no need to have another one.
Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20220628171850.1313069-5-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
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#
4f481208 |
| 08-Mar-2022 |
Ming Lei <ming.lei@redhat.com> |
blk-mq: prepare for implementing hctx table via xarray
It is inevitable to cause use-after-free on q->queue_hw_ctx between queue_for_each_hw_ctx() and blk_mq_update_nr_hw_queues(). And converting to
blk-mq: prepare for implementing hctx table via xarray
It is inevitable to cause use-after-free on q->queue_hw_ctx between queue_for_each_hw_ctx() and blk_mq_update_nr_hw_queues(). And converting to xarray can fix the uaf, meantime code gets cleaner.
Prepare for converting q->queue_hctx_ctx into xarray, one thing is that xa_for_each() can only accept 'unsigned long' as index, so changes type of hctx index of queue_for_each_hw_ctx() into 'unsigned long'.
Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220308073219.91173-6-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
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#
704b914f |
| 03-Dec-2021 |
Ming Lei <ming.lei@redhat.com> |
blk-mq: move srcu from blk_mq_hw_ctx to request_queue
In case of BLK_MQ_F_BLOCKING, per-hctx srcu is used to protect dispatch critical area. However, this srcu instance stays at the end of hctx, and
blk-mq: move srcu from blk_mq_hw_ctx to request_queue
In case of BLK_MQ_F_BLOCKING, per-hctx srcu is used to protect dispatch critical area. However, this srcu instance stays at the end of hctx, and it often takes standalone cacheline, often cold.
Inside srcu_read_lock() and srcu_read_unlock(), WRITE is always done on the indirect percpu variable which is allocated from heap instead of being embedded, srcu->srcu_idx is read only in srcu_read_lock(). It doesn't matter if srcu structure stays in hctx or request queue.
So switch to per-request-queue srcu for protecting dispatch, and this way simplifies quiesce a lot, not mention quiesce is always done on the request queue wide.
Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20211203131534.3668411-3-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
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#
2bc1f6e4 |
| 13-Jul-2021 |
Damien Le Moal <damien.lemoal@wdc.com> |
block: remove blk-mq-sysfs dead code
In block/blk-mq-sysfs.c, struct blk_mq_ctx_sysfs_entry is not used to define any attribute since the "mq" sysfs directory contains only sub-directories (no attri
block: remove blk-mq-sysfs dead code
In block/blk-mq-sysfs.c, struct blk_mq_ctx_sysfs_entry is not used to define any attribute since the "mq" sysfs directory contains only sub-directories (no attribute files). As a result, blk_mq_sysfs_show(), blk_mq_sysfs_store(), and struct sysfs_ops blk_mq_sysfs_ops are all unused and unnecessary. Remove all this unused code.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Link: https://lore.kernel.org/r/20210713081837.524422-1-damien.lemoal@wdc.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
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#
47ce030b |
| 09-Oct-2020 |
Yang Yang <yang.yang@vivo.com> |
blk-mq: move cancel of hctx->run_work to the front of blk_exit_queue
blk_exit_queue will free elevator_data, while blk_mq_run_work_fn will access it. Move cancel of hctx->run_work to the front of bl
blk-mq: move cancel of hctx->run_work to the front of blk_exit_queue
blk_exit_queue will free elevator_data, while blk_mq_run_work_fn will access it. Move cancel of hctx->run_work to the front of blk_exit_queue to avoid use-after-free.
Fixes: 1b97871b501f ("blk-mq: move cancel of hctx->run_work into blk_mq_hw_sysfs_release") Signed-off-by: Yang Yang <yang.yang@vivo.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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#
d2c9be89 |
| 04-Nov-2019 |
Ming Lei <ming.lei@redhat.com> |
blk-mq: make sure that line break can be printed
8962842ca5ab ("blk-mq: avoid sysfs buffer overflow with too many CPU cores") avoids sysfs buffer overflow, and reserves one character for line break.
blk-mq: make sure that line break can be printed
8962842ca5ab ("blk-mq: avoid sysfs buffer overflow with too many CPU cores") avoids sysfs buffer overflow, and reserves one character for line break. However, the last snprintf() doesn't get correct 'size' parameter passed in, so fixed it.
Fixes: 8962842ca5ab ("blk-mq: avoid sysfs buffer overflow with too many CPU cores") Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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#
8962842c |
| 02-Nov-2019 |
Ming Lei <ming.lei@redhat.com> |
blk-mq: avoid sysfs buffer overflow with too many CPU cores
It is reported that sysfs buffer overflow can be triggered if the system has too many CPU cores(>841 on 4K PAGE_SIZE) when showing CPUs of
blk-mq: avoid sysfs buffer overflow with too many CPU cores
It is reported that sysfs buffer overflow can be triggered if the system has too many CPU cores(>841 on 4K PAGE_SIZE) when showing CPUs of hctx via /sys/block/$DEV/mq/$N/cpu_list.
Use snprintf to avoid the potential buffer overflow.
This version doesn't change the attribute format, and simply stops showing CPU numbers if the buffer is going to overflow.
Cc: stable@vger.kernel.org Fixes: 676141e48af7("blk-mq: don't dump CPU -> hw queue map on driver load") Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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#
bae85c15 |
| 30-Sep-2019 |
Bart Van Assche <bvanassche@acm.org> |
block: Remove "dying" checks from sysfs callbacks
Block drivers must call del_gendisk() before blk_cleanup_queue(). del_gendisk() calls kobject_del() and kobject_del() waits until any ongoing sysfs
block: Remove "dying" checks from sysfs callbacks
Block drivers must call del_gendisk() before blk_cleanup_queue(). del_gendisk() calls kobject_del() and kobject_del() waits until any ongoing sysfs callback functions have finished. In other words, the sysfs callback functions won't be called for a queue in the dying state. Hence remove the "dying" checks from the sysfs callback functions.
Cc: Christoph Hellwig <hch@infradead.org> Cc: Ming Lei <ming.lei@redhat.com> Cc: Hannes Reinecke <hare@suse.com> Cc: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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#
cecf5d87 |
| 27-Aug-2019 |
Ming Lei <ming.lei@redhat.com> |
block: split .sysfs_lock into two locks
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.
Howeve
block: split .sysfs_lock into two locks
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>
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#
9685b227 |
| 27-Aug-2019 |
Bart Van Assche <bvanassche@acm.org> |
block: Remove blk_mq_register_dev()
This function has no callers. Hence remove it.
Cc: Christoph Hellwig <hch@infradead.org> Cc: Ming Lei <ming.lei@redhat.com> Cc: Hannes Reinecke <hare@suse.com> S
block: Remove blk_mq_register_dev()
This function has no callers. Hence remove it.
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>
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#
1b97871b |
| 30-Apr-2019 |
Ming Lei <ming.lei@redhat.com> |
blk-mq: move cancel of hctx->run_work into blk_mq_hw_sysfs_release
hctx is always released after requeue is freed.
With holding queue's kobject refcount, it is safe for driver to run queue, so one
blk-mq: move cancel of hctx->run_work into blk_mq_hw_sysfs_release
hctx is always released after requeue is freed.
With holding queue's kobject refcount, it is safe for driver to run queue, so one run queue might be scheduled after blk_sync_queue() is done.
So moving the cancel of hctx->run_work into blk_mq_hw_sysfs_release() for avoiding run released queue.
Cc: Dongli Zhang <dongli.zhang@oracle.com> Cc: James Smart <james.smart@broadcom.com> Cc: Bart Van Assche <bart.vanassche@wdc.com> Cc: linux-scsi@vger.kernel.org, Cc: Martin K . Petersen <martin.petersen@oracle.com>, Cc: Christoph Hellwig <hch@lst.de>, Cc: James E . J . Bottomley <jejb@linux.vnet.ibm.com>, Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Hannes Reinecke <hare@suse.com> Tested-by: James Smart <james.smart@broadcom.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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#
c7e2d94b |
| 30-Apr-2019 |
Ming Lei <ming.lei@redhat.com> |
blk-mq: free hw queue's resource in hctx's release handler
Once blk_cleanup_queue() returns, tags shouldn't be used any more, because blk_mq_free_tag_set() may be called. Commit 45a9c9d909b2 ("blk-m
blk-mq: free hw queue's resource in hctx's release handler
Once blk_cleanup_queue() returns, tags shouldn't be used any more, because blk_mq_free_tag_set() may be called. Commit 45a9c9d909b2 ("blk-mq: Fix a use-after-free") fixes this issue exactly.
However, that commit introduces another issue. Before 45a9c9d909b2, we are allowed to run queue during cleaning up queue if the queue's kobj refcount is held. After that commit, queue can't be run during queue cleaning up, otherwise oops can be triggered easily because some fields of hctx are freed by blk_mq_free_queue() in blk_cleanup_queue().
We have invented ways for addressing this kind of issue before, such as:
8dc765d438f1 ("SCSI: fix queue cleanup race before queue initialization is done") c2856ae2f315 ("blk-mq: quiesce queue before freeing queue")
But still can't cover all cases, recently James reports another such kind of issue:
https://marc.info/?l=linux-scsi&m=155389088124782&w=2
This issue can be quite hard to address by previous way, given scsi_run_queue() may run requeues for other LUNs.
Fixes the above issue by freeing hctx's resources in its release handler, and this way is safe becasue tags isn't needed for freeing such hctx resource.
This approach follows typical design pattern wrt. kobject's release handler.
Cc: Dongli Zhang <dongli.zhang@oracle.com> Cc: James Smart <james.smart@broadcom.com> Cc: Bart Van Assche <bart.vanassche@wdc.com> Cc: linux-scsi@vger.kernel.org, Cc: Martin K . Petersen <martin.petersen@oracle.com>, Cc: Christoph Hellwig <hch@lst.de>, Cc: James E . J . Bottomley <jejb@linux.vnet.ibm.com>, Reported-by: James Smart <james.smart@broadcom.com> Fixes: 45a9c9d909b2 ("blk-mq: Fix a use-after-free") Cc: stable@vger.kernel.org Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Tested-by: James Smart <james.smart@broadcom.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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3dcf60bc |
| 30-Apr-2019 |
Christoph Hellwig <hch@lst.de> |
block: add SPDX tags to block layer files missing licensing information
Various block layer files do not have any licensing information at all. Add SPDX tags for the default kernel GPLv2 license to
block: add SPDX tags to block layer files missing licensing information
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>
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800f5aa1 |
| 02-Apr-2019 |
Kimberly Brown <kimbrownkd@gmail.com> |
block: Replace all ktype default_attrs with groups
The kobj_type default_attrs field is being replaced by the default_groups field. Replace all of the ktype default_attrs fields in the block subsyst
block: Replace all ktype default_attrs with groups
The kobj_type default_attrs field is being replaced by the default_groups field. Replace all of the ktype default_attrs fields in the block subsystem with default_groups and use the ATTRIBUTE_GROUPS macro to create the default groups.
Remove default_ctx_attrs[] because it doesn't contain any attributes.
This patch was tested by verifying that the sysfs files for the attributes in the default groups were created.
Signed-off-by: Kimberly Brown <kimbrownkd@gmail.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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346fc108 |
| 17-Dec-2018 |
Ming Lei <ming.lei@redhat.com> |
blk-mq: export hctx->type in debugfs instead of sysfs
Now we only export hctx->type via sysfs, and there isn't such info in hctx entry under debugfs. We often use debugfs only to diagnose queue mapp
blk-mq: export hctx->type in debugfs instead of sysfs
Now we only export hctx->type via sysfs, and there isn't such info in hctx entry under debugfs. We often use debugfs only to diagnose queue mapping issue, so add the support in debugfs.
Queue mapping becomes a bit more complicated after multiple queue mapping is supported, we may write blktest to verify if queue mapping is valid based on blk-mq-debugfs.
Given not necessary to export hctx->type twice, so remove the export from sysfs.
Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Mike Snitzer <snitzer@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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e20ba6e1 |
| 02-Dec-2018 |
Christoph Hellwig <hch@lst.de> |
block: move queues types to the block layer
Having another indirect all in the fast path doesn't really help in our post-spectre world. Also having too many queue type is just going to create confu
block: move queues types to the block layer
Having another indirect all in the fast path doesn't really help in our post-spectre world. Also having too many queue type is just going to create confusion, so I'd rather manage them centrally.
Note that the queue type naming and ordering changes a bit - the first index now is the default queue for everything not explicitly marked, the optional ones are read and poll queues.
Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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1db4909e |
| 20-Nov-2018 |
Ming Lei <ming.lei@redhat.com> |
blk-mq: not embed .mq_kobj and ctx->kobj into queue instance
Even though .mq_kobj, ctx->kobj and q->kobj share same lifetime from block layer's view, actually they don't because userspace may grab o
blk-mq: not embed .mq_kobj and ctx->kobj into queue instance
Even though .mq_kobj, ctx->kobj and q->kobj share same lifetime from block layer's view, actually they don't because userspace may grab one kobject anytime via sysfs.
This patch fixes the issue by the following approach:
1) introduce 'struct blk_mq_ctxs' for holding .mq_kobj and managing all ctxs
2) free all allocated ctxs and the 'blk_mq_ctxs' instance in release handler of .mq_kobj
3) grab one ref of .mq_kobj before initializing each ctx->kobj, so that .mq_kobj is always released after all ctxs are freed.
This patch fixes kernel panic issue during booting when DEBUG_KOBJECT_RELEASE is enabled.
Reported-by: Guenter Roeck <linux@roeck-us.net> Cc: "jianchao.wang" <jianchao.w.wang@oracle.com> Tested-by: Guenter Roeck <linux@roeck-us.net> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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b6676f65 |
| 14-Nov-2018 |
Christoph Hellwig <hch@lst.de> |
block: remove a few unused exports
Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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