- 18 12月, 2019 1 次提交
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由 Ming Lei 提交于
commit 8962842ca5abdcf98e22ab3b2b45a103f0408b95 upstream. 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: 676141e4("blk-mq: don't dump CPU -> hw queue map on driver load") Signed-off-by: NMing Lei <ming.lei@redhat.com> Signed-off-by: NJens Axboe <axboe@kernel.dk> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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- 16 9月, 2019 1 次提交
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由 Ming Lei 提交于
[ Upstream commit c7e2d94b3d1634988a95ac4d77a72dc7487ece06 ] Once blk_cleanup_queue() returns, tags shouldn't be used any more, because blk_mq_free_tag_set() may be called. Commit 45a9c9d9 ("blk-mq: Fix a use-after-free") fixes this issue exactly. However, that commit introduces another issue. Before 45a9c9d9, 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") c2856ae2 ("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: NJames Smart <james.smart@broadcom.com> Fixes: 45a9c9d9 ("blk-mq: Fix a use-after-free") Cc: stable@vger.kernel.org Reviewed-by: NHannes Reinecke <hare@suse.com> Reviewed-by: NChristoph Hellwig <hch@lst.de> Tested-by: NJames Smart <james.smart@broadcom.com> Signed-off-by: NMing Lei <ming.lei@redhat.com> Signed-off-by: NJens Axboe <axboe@kernel.dk> Signed-off-by: NSasha Levin <sashal@kernel.org>
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- 25 5月, 2018 1 次提交
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由 Joe Perches 提交于
Convert the S_<FOO> symbolic permissions to their octal equivalents as using octal and not symbolic permissions is preferred by many as more readable. see: https://lkml.org/lkml/2016/8/2/1945 Done with automated conversion via: $ ./scripts/checkpatch.pl -f --types=SYMBOLIC_PERMS --fix-inplace <files...> Miscellanea: o Wrapped modified multi-line calls to a single line where appropriate o Realign modified multi-line calls to open parenthesis Signed-off-by: NJoe Perches <joe@perches.com> Signed-off-by: NJens Axboe <axboe@kernel.dk>
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- 15 1月, 2018 1 次提交
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由 Mike Snitzer 提交于
The original commit e9a823fb (block: fix warning when I/O elevator is changed as request_queue is being removed) is pretty conflated. "conflated" because the resource being protected by q->sysfs_lock isn't the queue_flags (it is the 'queue' kobj). q->sysfs_lock serializes __elevator_change() (via elv_iosched_store) from racing with blk_unregister_queue(): 1) By holding q->sysfs_lock first, __elevator_change() can complete before a racing blk_unregister_queue(). 2) Conversely, __elevator_change() is testing for QUEUE_FLAG_REGISTERED in case elv_iosched_store() loses the race with blk_unregister_queue(), it needs a way to know the 'queue' kobj isn't there. Expand the scope of blk_unregister_queue()'s q->sysfs_lock use so it is held until after the 'queue' kobj is removed. To do so blk_mq_unregister_dev() must not also take q->sysfs_lock. So rename __blk_mq_unregister_dev() to blk_mq_unregister_dev(). Also, blk_unregister_queue() should use q->queue_lock to protect against any concurrent writes to q->queue_flags -- even though chances are the queue is being cleaned up so no concurrent writes are likely. Fixes: e9a823fb ("block: fix warning when I/O elevator is changed as request_queue is being removed") Signed-off-by: NMike Snitzer <snitzer@redhat.com> Reviewed-by: NMing Lei <ming.lei@redhat.com> Signed-off-by: NJens Axboe <axboe@kernel.dk>
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- 04 5月, 2017 2 次提交
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由 Omar Sandoval 提交于
Originally, I tied debugfs registration/unregistration together with sysfs. There's no reason to do this, and it's getting in the way of letting schedulers define their own debugfs attributes. Instead, tie the debugfs registration to the lifetime of the structures themselves. The saner lifetimes mean we can also get rid of the extra mq directory and move everything one level up. I.e., nvme0n1/mq/hctx0/tags is now just nvme0n1/hctx0/tags. Signed-off-by: NOmar Sandoval <osandov@fb.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Omar Sandoval 提交于
Preparation for adding more declarations. Signed-off-by: NOmar Sandoval <osandov@fb.com> Reviewed-by: NHannes Reinecke <hare@suse.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 27 4月, 2017 4 次提交
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由 Bart Van Assche 提交于
Hctx unregistration involves calling kobject_del(). kobject_del() must not be called if kobject_add() has not been called. Hence in the error path only unregister hctxs for which registration succeeded. Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com> Cc: Omar Sandoval <osandov@fb.com> Cc: Hannes Reinecke <hare@suse.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Bart Van Assche 提交于
Since the blk_mq_debugfs_*register_hctxs() functions register and unregister all attributes under the "mq" directory, rename these into blk_mq_debugfs_*register_mq(). Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: NHannes Reinecke <hare@suse.com> Reviewed-by: NOmar Sandoval <osandov@fb.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Bart Van Assche 提交于
A later patch will move the call of blk_mq_debugfs_register() to a function to which the queue name is not passed as an argument. To avoid having to add a 'name' argument to multiple callers, let blk_mq_debugfs_register() look up the queue name. Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: NOmar Sandoval <osandov@fb.com> Reviewed-by: NHannes Reinecke <hare@suse.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Bart Van Assche 提交于
A later patch in this series will modify blk_mq_debugfs_register() such that it uses q->kobj.parent to determine the name of a request queue. Hence make sure that that pointer is initialized before blk_mq_debugfs_register() is called. To avoid lock inversion, protect sysfs / debugfs registration with the queue sysfs_lock instead of the global mutex all_q_mutex. Signed-off-by: NBart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: NHannes Reinecke <hare@suse.com> Reviewed-by: NOmar Sandoval <osandov@fb.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 09 3月, 2017 4 次提交
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由 Ming Lei 提交于
It is obviously that hctx->cpumask is per hctx, and both share same lifetime, so this patch moves freeing of hctx->cpumask into release handler of hctx's kobject. Signed-off-by: NMing Lei <tom.leiming@gmail.com> Tested-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Ming Lei 提交于
This patch removes kobject_put() over hctx in __blk_mq_unregister_dev(), and trys to keep lifetime consistent between hctx and hctx's kobject. Now blk_mq_sysfs_register() and blk_mq_sysfs_unregister() become totally symmetrical, and kobject's refcounter drops to zero just when the hctx is freed. Signed-off-by: NMing Lei <tom.leiming@gmail.com> Tested-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Ming Lei 提交于
Currently from kobject view, both q->mq_kobj and ctx->kobj can be released during one cycle of blk_mq_register_dev() and blk_mq_unregister_dev(). Actually, sw queue's lifetime is same with its request queue's, which is covered by request_queue->kobj. So we don't need to call kobject_put() for the two kinds of kobject in __blk_mq_unregister_dev(), instead we do that in release handler of request queue. Signed-off-by: NMing Lei <tom.leiming@gmail.com> Tested-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Ming Lei 提交于
Both q->mq_kobj and sw queues' kobjects should have been initialized once, instead of doing that each add_disk context. Also this patch removes clearing of ctx in blk_mq_init_cpu_queues() because percpu allocator fills zero to allocated variable. This patch fixes one issue[1] reported from Omar. [1] kernel wearning when doing unbind/bind on one scsi-mq device [ 19.347924] kobject (ffff8800791ea0b8): tried to init an initialized object, something is seriously wrong. [ 19.349781] CPU: 1 PID: 84 Comm: kworker/u8:1 Not tainted 4.10.0-rc7-00210-g53f39eeaa263 #34 [ 19.350686] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.1-20161122_114906-anatol 04/01/2014 [ 19.350920] Workqueue: events_unbound async_run_entry_fn [ 19.350920] Call Trace: [ 19.350920] dump_stack+0x63/0x83 [ 19.350920] kobject_init+0x77/0x90 [ 19.350920] blk_mq_register_dev+0x40/0x130 [ 19.350920] blk_register_queue+0xb6/0x190 [ 19.350920] device_add_disk+0x1ec/0x4b0 [ 19.350920] sd_probe_async+0x10d/0x1c0 [sd_mod] [ 19.350920] async_run_entry_fn+0x48/0x150 [ 19.350920] process_one_work+0x1d0/0x480 [ 19.350920] worker_thread+0x48/0x4e0 [ 19.350920] kthread+0x101/0x140 [ 19.350920] ? process_one_work+0x480/0x480 [ 19.350920] ? kthread_create_on_node+0x60/0x60 [ 19.350920] ret_from_fork+0x2c/0x40 Cc: Omar Sandoval <osandov@osandov.com> Signed-off-by: NMing Lei <tom.leiming@gmail.com> Tested-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 03 2月, 2017 1 次提交
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由 Omar Sandoval 提交于
This needs to happen after we tear down blktrace. Signed-off-by: NOmar Sandoval <osandov@fb.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 27 1月, 2017 5 次提交
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由 Omar Sandoval 提交于
These counters aren't as out-of-place in sysfs as the other stuff, but debugfs is a slightly better home for them. Reviewed-by: NHannes Reinecke <hare@suse.com> Signed-off-by: NOmar Sandoval <osandov@fb.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Omar Sandoval 提交于
These statistics _might_ be useful to userspace, but it's better not to commit to an ABI for these yet. Also, the dispatched file in sysfs couldn't be cleared, so make it clearable like the others in debugfs. Reviewed-by: NHannes Reinecke <hare@suse.com> Signed-off-by: NOmar Sandoval <osandov@fb.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Omar Sandoval 提交于
These are very tied to the blk-mq tag implementation, so exposing them to sysfs isn't a great idea. Move the debugging information to debugfs and add basic entries for the number of tags and the number of reserved tags to sysfs. Reviewed-by: NHannes Reinecke <hare@suse.com> Signed-off-by: NOmar Sandoval <osandov@fb.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Omar Sandoval 提交于
These lists are only useful for debugging; they definitely don't belong in sysfs. Putting them in debugfs also removes the limitation of a single page of output. Reviewed-by: NHannes Reinecke <hare@suse.com> Signed-off-by: NOmar Sandoval <osandov@fb.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Omar Sandoval 提交于
In preparation for putting blk-mq debugging information in debugfs, create a directory tree mirroring the one in sysfs: # tree -d /sys/kernel/debug/block /sys/kernel/debug/block |-- nvme0n1 | `-- mq | |-- 0 | | `-- cpu0 | |-- 1 | | `-- cpu1 | |-- 2 | | `-- cpu2 | `-- 3 | `-- cpu3 `-- vda `-- mq `-- 0 |-- cpu0 |-- cpu1 |-- cpu2 `-- cpu3 Also add the scaffolding for the actual files that will go in here, either under the hardware queue or software queue directories. Reviewed-by: NHannes Reinecke <hare@suse.com> Signed-off-by: NOmar Sandoval <osandov@fb.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 18 1月, 2017 1 次提交
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由 Jens Axboe 提交于
This adds a set of hooks that intercepts the blk-mq path of allocating/inserting/issuing/completing requests, allowing us to develop a scheduler within that framework. We reuse the existing elevator scheduler API on the registration side, but augment that with the scheduler flagging support for the blk-mq interfce, and with a separate set of ops hooks for MQ devices. We split driver and scheduler tags, so we can run the scheduling independently of device queue depth. Signed-off-by: NJens Axboe <axboe@fb.com> Reviewed-by: NBart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: NOmar Sandoval <osandov@fb.com>
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- 11 11月, 2016 1 次提交
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由 Jens Axboe 提交于
For legacy block, we simply track them in the request queue. For blk-mq, we track them on a per-sw queue basis, which we can then sum up through the hardware queues and finally to a per device state. The stats are tracked in, roughly, 0.1s interval windows. Add sysfs files to display the stats. The feature is off by default, to avoid any extra overhead. In-kernel users of it can turn it on by setting QUEUE_FLAG_STATS in the queue flags. We currently don't turn it on if someone just reads any of the stats files, that is something we could add as well. Signed-off-by: NJens Axboe <axboe@fb.com>
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- 21 9月, 2016 1 次提交
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由 Matias Bjørling 提交于
Enable devices without a gendisk instance to register itself with blk-mq and expose the associated multi-queue sysfs entries. Signed-off-by: NMatias Bjørling <m@bjorling.me> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 17 9月, 2016 1 次提交
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由 Jens Axboe 提交于
We currently account a '0' dispatch, and anything above that still falls below the range set by BLK_MQ_MAX_DISPATCH_ORDER. If we dispatch more, we don't account it. Change the last bucket to be inclusive of anything above the range we track, and have the sysfs file reflect that by including a '+' in the output: $ cat /sys/block/nvme0n1/mq/0/dispatched 0 1006 1 20229 2 1 4 0 8 0 16 0 32+ 0 Signed-off-by: NJens Axboe <axboe@fb.com> Reviewed-by: NOmar Sandoval <osandov@fb.com>
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- 14 9月, 2016 2 次提交
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由 Stephen Bates 提交于
Allow the io_poll statistics to be zeroed to make for easier logging of polling event. Signed-off-by: NStephen Bates <sbates@raithlin.com> Acked-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Stephen Bates 提交于
In order to help determine the effectiveness of polling in a running system it is usful to determine the ratio of how often the poll function is called vs how often the completion is checked. For this reason we add a poll_considered variable and add it to the sysfs entry for io_poll. Signed-off-by: NStephen Bates <sbates@raithlin.com> Acked-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 05 8月, 2016 1 次提交
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由 Jens Axboe 提交于
If we fail registering any of the hardware queues, we call into blk_mq_unregister_disk() with the hotplug mutex already held. Since blk_mq_unregister_disk() attempts to acquire the same mutex, we end up in a less than happy place. Reported-by: NJinpu Wang <jinpu.wang@profitbricks.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 20 3月, 2016 1 次提交
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由 Thomas Gleixner 提交于
queue_for_each_ctx() iterates over per_cpu variables under the assumption that the possible cpu mask cannot have holes. That's wrong as all cpumasks can have holes. In case there are holes the iteration ends up accessing uninitialized memory and crashing as a result. Replace the macro by a proper for_each_possible_cpu() loop and drop the unused macro blk_ctx_sum() which references queue_for_each_ctx(). Reported-by: NXiong Zhou <jencce.kernel@gmail.com> Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 10 2月, 2016 1 次提交
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由 Keith Busch 提交于
The hardware's provided queue count may change at runtime with resource provisioning. This patch allows a block driver to alter the number of h/w queues available when its resource count changes. The main part is a new blk-mq API to request a new number of h/w queues for a given live tag set. The new API freezes all queues using that set, then adjusts the allocated count prior to remapping these to CPUs. The bulk of the rest just shifts where h/w contexts and all their artifacts are allocated and freed. The number of max h/w contexts is capped to the number of possible cpus since there is no use for more than that. As such, all pre-allocated memory for pointers need to account for the max possible rather than the initial number of queues. A side effect of this is that the blk-mq will proceed successfully as long as it can allocate at least one h/w context. Previously it would fail request queue initialization if less than the requested number was allocated. Signed-off-by: NKeith Busch <keith.busch@intel.com> Reviewed-by: NChristoph Hellwig <hch@lst.de> Tested-by: NJon Derrick <jonathan.derrick@intel.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 08 11月, 2015 1 次提交
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由 Jens Axboe 提交于
Add basic support for polling for specific IO to complete. This uses the cookie that blk-mq passes back, which enables the block layer to pass this cookie to the driver to spin for a specific request. This will be combined with request latency tracking, so we can make qualified decisions about when to poll and when not to. For now, for benchmark purposes, we add a sysfs file that controls whether polling is enabled or not. Signed-off-by: NJens Axboe <axboe@fb.com> Acked-by: NChristoph Hellwig <hch@lst.de> Acked-by: NKeith Busch <keith.busch@intel.com>
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- 22 10月, 2015 1 次提交
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由 Dan Williams 提交于
Allow pmem, and other synchronous/bio-based block drivers, to fallback on a per-cpu reference count managed by the core for tracking queue live/dead state. The existing per-cpu reference count for the blk_mq case is promoted to be used in all block i/o scenarios. This involves initializing it by default, waiting for it to drop to zero at exit, and holding a live reference over the invocation of q->make_request_fn() in generic_make_request(). The blk_mq code continues to take its own reference per blk_mq request and retains the ability to freeze the queue, but the check that the queue is frozen is moved to generic_make_request(). This fixes crash signatures like the following: BUG: unable to handle kernel paging request at ffff880140000000 [..] Call Trace: [<ffffffff8145e8bf>] ? copy_user_handle_tail+0x5f/0x70 [<ffffffffa004e1e0>] pmem_do_bvec.isra.11+0x70/0xf0 [nd_pmem] [<ffffffffa004e331>] pmem_make_request+0xd1/0x200 [nd_pmem] [<ffffffff811c3162>] ? mempool_alloc+0x72/0x1a0 [<ffffffff8141f8b6>] generic_make_request+0xd6/0x110 [<ffffffff8141f966>] submit_bio+0x76/0x170 [<ffffffff81286dff>] submit_bh_wbc+0x12f/0x160 [<ffffffff81286e62>] submit_bh+0x12/0x20 [<ffffffff813395bd>] jbd2_write_superblock+0x8d/0x170 [<ffffffff8133974d>] jbd2_mark_journal_empty+0x5d/0x90 [<ffffffff813399cb>] jbd2_journal_destroy+0x24b/0x270 [<ffffffff810bc4ca>] ? put_pwq_unlocked+0x2a/0x30 [<ffffffff810bc6f5>] ? destroy_workqueue+0x225/0x250 [<ffffffff81303494>] ext4_put_super+0x64/0x360 [<ffffffff8124ab1a>] generic_shutdown_super+0x6a/0xf0 Cc: Jens Axboe <axboe@kernel.dk> Cc: Keith Busch <keith.busch@intel.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Suggested-by: NChristoph Hellwig <hch@lst.de> Reviewed-by: NChristoph Hellwig <hch@lst.de> Tested-by: NRoss Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: NDan Williams <dan.j.williams@intel.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 30 9月, 2015 2 次提交
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由 Akinobu Mita 提交于
CPU hotplug handling for blk-mq (blk_mq_queue_reinit) acquires all_q_mutex in blk_mq_queue_reinit_notify() and then removes sysfs entries by blk_mq_sysfs_unregister(). Removing sysfs entry needs to be blocked until the active reference of the kernfs_node to be zero. On the other hand, reading blk_mq_hw_sysfs_cpu sysfs entry (e.g. /sys/block/nullb0/mq/0/cpu_list) acquires all_q_mutex in blk_mq_hw_sysfs_cpus_show(). If these happen at the same time, a deadlock can happen. Because one can wait for the active reference to be zero with holding all_q_mutex, and the other tries to acquire all_q_mutex with holding the active reference. The reason that all_q_mutex is acquired in blk_mq_hw_sysfs_cpus_show() is to avoid reading an imcomplete hctx->cpumask. Since reading sysfs entry for blk-mq needs to acquire q->sysfs_lock, we can avoid deadlock and reading an imcomplete hctx->cpumask by protecting q->sysfs_lock while hctx->cpumask is being updated. Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com> Reviewed-by: NMing Lei <tom.leiming@gmail.com> Cc: Ming Lei <tom.leiming@gmail.com> Cc: Wanpeng Li <wanpeng.li@hotmail.com> Reviewed-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NJens Axboe <axboe@fb.com>
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由 Akinobu Mita 提交于
There is a race between cpu hotplug handling and adding/deleting gendisk for blk-mq, where both are trying to register and unregister the same sysfs entries. null_add_dev --> blk_mq_init_queue --> blk_mq_init_allocated_queue --> add to 'all_q_list' (*) --> add_disk --> blk_register_queue --> blk_mq_register_disk (++) null_del_dev --> del_gendisk --> blk_unregister_queue --> blk_mq_unregister_disk (--) --> blk_cleanup_queue --> blk_mq_free_queue --> del from 'all_q_list' (*) blk_mq_queue_reinit --> blk_mq_sysfs_unregister (-) --> blk_mq_sysfs_register (+) While the request queue is added to 'all_q_list' (*), blk_mq_queue_reinit() can be called for the queue anytime by CPU hotplug callback. But blk_mq_sysfs_unregister (-) and blk_mq_sysfs_register (+) in blk_mq_queue_reinit must not be called before blk_mq_register_disk (++) and after blk_mq_unregister_disk (--) is finished. Because '/sys/block/*/mq/' is not exists. There has already been BLK_MQ_F_SYSFS_UP flag in hctx->flags which can be used to track these sysfs stuff, but it is only fixing this issue partially. In order to fix it completely, we just need per-queue flag instead of per-hctx flag with appropriate locking. So this introduces q->mq_sysfs_init_done which is properly protected with all_q_mutex. Also, we need to ensure that blk_mq_map_swqueue() is called with all_q_mutex is held. Since hctx->nr_ctx is reset temporarily and updated in blk_mq_map_swqueue(), so we should avoid blk_mq_register_hctx() seeing the temporary hctx->nr_ctx value in CPU hotplug handling or adding/deleting gendisk . Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com> Reviewed-by: NMing Lei <tom.leiming@gmail.com> Cc: Ming Lei <tom.leiming@gmail.com> Reviewed-by: NChristoph Hellwig <hch@lst.de> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 15 8月, 2015 1 次提交
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由 Ming Lei 提交于
There may be lots of pending requests so that the buffer of PAGE_SIZE can't hold them at all. One typical example is scsi-mq, the queue depth(.can_queue) of scsi_host and blk-mq is quite big but scsi_device's queue_depth is a bit small(.cmd_per_lun), then it is quite easy to have lots of pending requests in hw queue. This patch fixes the following warning and the related memory destruction. [ 359.025101] fill_read_buffer: blk_mq_hw_sysfs_show+0x0/0x7d returned bad count^M [ 359.055595] irq event stamp: 15537^M [ 359.055606] general protection fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC ^M [ 359.055614] Dumping ftrace buffer:^M [ 359.055660] (ftrace buffer empty)^M [ 359.055672] Modules linked in: nbd ipv6 kvm_intel kvm serio_raw^M [ 359.055678] CPU: 4 PID: 21631 Comm: stress-ng-sysfs Not tainted 4.2.0-rc5-next-20150805 #434^M [ 359.055679] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011^M [ 359.055682] task: ffff8802161cc000 ti: ffff88021b4a8000 task.ti: ffff88021b4a8000^M [ 359.055693] RIP: 0010:[<ffffffff811541c5>] [<ffffffff811541c5>] __kmalloc+0xe8/0x152^M Cc: <stable@vger.kernel.org> Signed-off-by: NMing Lei <ming.lei@canonical.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 13 3月, 2015 1 次提交
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由 Mike Snitzer 提交于
Add a variant of blk_mq_init_queue that allows a previously allocated queue to be initialized. blk_mq_init_allocated_queue models blk_init_allocated_queue -- which was also created for DM's use. DM's approach to device creation requires a placeholder request_queue be allocated for use with alloc_dev() but the decision about what type of request_queue will be ultimately created is deferred until all component devices referenced in the DM table are processed to determine the table type (request-based, blk-mq request-based, or bio-based). Also, because of DM's late finalization of the request_queue type the call to blk_mq_register_disk() doesn't happen during alloc_dev(). Must export blk_mq_register_disk() so that DM can backfill the 'mq' dir once the blk-mq queue is fully allocated. Signed-off-by: NMike Snitzer <snitzer@redhat.com> Reviewed-by: NMing Lei <ming.lei@canonical.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 30 1月, 2015 1 次提交
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由 Ming Lei 提交于
This reverts commit 76d697d1. The commit 76d697d1 causes general protection fault reported from Bart Van Assche: https://lkml.org/lkml/2015/1/28/334Reported-by: NBart Van Assche <bart.vanassche@sandisk.com> Signed-off-by: NMing Lei <ming.lei@canonical.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 21 1月, 2015 1 次提交
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由 Ming Lei 提交于
The kobject memory shouldn't have been freed before the kobject is released because driver core can access it freely before its release. This patch frees hctx in its release callback. For ctx, they share one single per-cpu variable which is associated with the request queue, so free ctx in q->mq_kobj's release handler. Signed-off-by: NSasha Levin <sasha.levin@oracle.com> (fix ctx kobjects) Signed-off-by: NMing Lei <ming.lei@canonical.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 10 12月, 2014 1 次提交
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由 Takashi Iwai 提交于
When a CPU is hotplugged, the current blk-mq spews a warning like: kobject '(null)' (ffffe8ffffc8b5d8): tried to add an uninitialized object, something is seriously wrong. CPU: 1 PID: 1386 Comm: systemd-udevd Not tainted 3.18.0-rc7-2.g088d59b-default #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_171129-lamiak 04/01/2014 0000000000000000 0000000000000002 ffffffff81605f07 ffffe8ffffc8b5d8 ffffffff8132c7a0 ffff88023341d370 0000000000000020 ffff8800bb05bd58 ffff8800bb05bd08 000000000000a0a0 000000003f441940 0000000000000007 Call Trace: [<ffffffff81005306>] dump_trace+0x86/0x330 [<ffffffff81005644>] show_stack_log_lvl+0x94/0x170 [<ffffffff81006d21>] show_stack+0x21/0x50 [<ffffffff81605f07>] dump_stack+0x41/0x51 [<ffffffff8132c7a0>] kobject_add+0xa0/0xb0 [<ffffffff8130aee1>] blk_mq_register_hctx+0x91/0xb0 [<ffffffff8130b82e>] blk_mq_sysfs_register+0x3e/0x60 [<ffffffff81309298>] blk_mq_queue_reinit_notify+0xf8/0x190 [<ffffffff8107cfdc>] notifier_call_chain+0x4c/0x70 [<ffffffff8105fd23>] cpu_notify+0x23/0x50 [<ffffffff81060037>] _cpu_up+0x157/0x170 [<ffffffff810600d9>] cpu_up+0x89/0xb0 [<ffffffff815fa5b5>] cpu_subsys_online+0x35/0x80 [<ffffffff814323cd>] device_online+0x5d/0xa0 [<ffffffff81432485>] online_store+0x75/0x80 [<ffffffff81236a5a>] kernfs_fop_write+0xda/0x150 [<ffffffff811c5532>] vfs_write+0xb2/0x1f0 [<ffffffff811c5f42>] SyS_write+0x42/0xb0 [<ffffffff8160c4ed>] system_call_fastpath+0x16/0x1b [<00007f0132fb24e0>] 0x7f0132fb24e0 This is indeed because of an uninitialized kobject for blk_mq_ctx. The blk_mq_ctx kobjects are initialized in blk_mq_sysfs_init(), but it goes loop over hctx_for_each_ctx(), i.e. it initializes only for online CPUs. Thus, when a CPU is hotplugged, the ctx for the newly onlined CPU is registered without initialization. This patch fixes the issue by initializing the all ctx kobjects belonging to each queue. Bugzilla: https://bugzilla.novell.com/show_bug.cgi?id=908794 Cc: <stable@vger.kernel.org> Signed-off-by: NTakashi Iwai <tiwai@suse.de> Signed-off-by: NJens Axboe <axboe@fb.com>
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- 25 9月, 2014 1 次提交
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由 Tejun Heo 提交于
blk-mq uses percpu_ref for its usage counter which tracks the number of in-flight commands and used to synchronously drain the queue on freeze. percpu_ref shutdown takes measureable wallclock time as it involves a sched RCU grace period. This means that draining a blk-mq takes measureable wallclock time. One would think that this shouldn't matter as queue shutdown should be a rare event which takes place asynchronously w.r.t. userland. Unfortunately, SCSI probing involves synchronously setting up and then tearing down a lot of request_queues back-to-back for non-existent LUNs. This means that SCSI probing may take above ten seconds when scsi-mq is used. [ 0.949892] scsi host0: Virtio SCSI HBA [ 1.007864] scsi 0:0:0:0: Direct-Access QEMU QEMU HARDDISK 1.1. PQ: 0 ANSI: 5 [ 1.021299] scsi 0:0:1:0: Direct-Access QEMU QEMU HARDDISK 1.1. PQ: 0 ANSI: 5 [ 1.520356] tsc: Refined TSC clocksource calibration: 2491.910 MHz <stall> [ 16.186549] sd 0:0:0:0: Attached scsi generic sg0 type 0 [ 16.190478] sd 0:0:1:0: Attached scsi generic sg1 type 0 [ 16.194099] osd: LOADED open-osd 0.2.1 [ 16.203202] sd 0:0:0:0: [sda] 31457280 512-byte logical blocks: (16.1 GB/15.0 GiB) [ 16.208478] sd 0:0:0:0: [sda] Write Protect is off [ 16.211439] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA [ 16.218771] sd 0:0:1:0: [sdb] 31457280 512-byte logical blocks: (16.1 GB/15.0 GiB) [ 16.223264] sd 0:0:1:0: [sdb] Write Protect is off [ 16.225682] sd 0:0:1:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA This is also the reason why request_queues start in bypass mode which is ended on blk_register_queue() as shutting down a fully functional queue also involves a RCU grace period and the queues for non-existent SCSI devices never reach registration. blk-mq basically needs to do the same thing - start the mq in a degraded mode which is faster to shut down and then make it fully functional only after the queue reaches registration. percpu_ref recently grew facilities to force atomic operation until explicitly switched to percpu mode, which can be used for this purpose. This patch makes blk-mq initialize q->mq_usage_counter in atomic mode and switch it to percpu mode only once blk_register_queue() is reached. Note that this issue was previously worked around by 0a30288d ("blk-mq, percpu_ref: implement a kludge for SCSI blk-mq stall during probe") for v3.17. The temp fix was reverted in preparation of adding persistent atomic mode to percpu_ref by 9eca8046 ("Revert "blk-mq, percpu_ref: implement a kludge for SCSI blk-mq stall during probe""). This patch and the prerequisite percpu_ref changes will be merged during v3.18 devel cycle. Signed-off-by: NTejun Heo <tj@kernel.org> Reported-by: NChristoph Hellwig <hch@infradead.org> Link: http://lkml.kernel.org/g/20140919113815.GA10791@lst.de Fixes: add703fd ("blk-mq: use percpu_ref for mq usage count") Reviewed-by: NKent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Johannes Weiner <hannes@cmpxchg.org>
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- 31 5月, 2014 1 次提交
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由 Fengguang Wu 提交于
CC: Jens Axboe <axboe@kernel.dk> Signed-off-by: NFengguang Wu <fengguang.wu@intel.com> Signed-off-by: NJens Axboe <axboe@fb.com>
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