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Many userspace tools and services use the proportional-share policy of
the blkio/io cgroups controller. The CFQ I/O scheduler implemented
this policy for the legacy block layer. To modify the weight of a
group in case CFQ was in charge, the 'weight' parameter of the group
must be modified. On the other hand, the BFQ I/O scheduler implements
the same policy in blk-mq, but, with BFQ, the parameter to modify has
a different name: bfq.weight (forced choice until legacy block was
present, because two different policies cannot share a common parameter
in cgroups).
Due to CFQ legacy, most if not all userspace configurations still use
the parameter 'weight', and for the moment do not seem likely to be
changed. But, when CFQ went away with legacy block, such a parameter
ceased to exist.
So, a simple workaround has been proposed [1] to make all
configurations work: add a symlink, named weight, to bfq.weight. This
commit adds such a symlink.
[1] https://lkml.org/lkml/2019/4/8/555
Suggested-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Angelo Ruocco <angeloruocco90@gmail.com>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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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>
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IS_ERR(_OR_NULL) already contain an 'unlikely' compiler flag,
so no need to do that again from its callers. Drop it.
Cc: Jens Axboe <axboe@kernel.dk>
Cc: linux-block@vger.kernel.org
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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While troubleshooting issues where cloned request limits have been
exceeded, it is often beneficial to know the actual values that
have been breached. Print these values, assisting in ease of
identification of root cause of the breach.
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: John Pittman <jpittman@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Document the meaning of the blk_mq_hw_queue_to_node() arguments.
Reviewed-by: Chaitanya Kulkarni <chiatanya.kulkarni@wdc.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Change one occurrence of 'performace' into 'performance'.
Cc: Max Gurtovoy <maxg@mellanox.com>
Fixes: fe631457ff3e ("blk-mq: map all HWQ also in hyperthreaded system") # v4.13.
Reviewed-by: Chaitanya Kulkarni <chiatanya.kulkarni@wdc.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Document all bsg_setup_queue() arguments as required.
Fixes: aae3b069d5ce ("bsg: pass in desired timeout handler") # v5.0.
Reviewed-by: Chaitanya Kulkarni <chiatanya.kulkarni@wdc.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Add documentation for the @rqw argument and change " - " into ": ".
Fixes: 84f603246db9 ("block: add rq_qos_wait to rq_qos") # v5.0-rc1~52^2~140.
Reviewed-by: Chaitanya Kulkarni <chiatanya.kulkarni@wdc.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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This patch avoids that the kernel-doc script complains about these
function headers when building with W=1.
Cc: Hannes Reinecke <hare@suse.com>
Cc: Keith Busch <keith.busch@intel.com>
Fixes: ed76e329d74a ("blk-mq: abstract out queue map") # v5.0.
Fixes: e42b3867de4b ("blk-mq-rdma: pass in queue map to blk_mq_rdma_map_queues") # v5.0.
Reviewed-by: Chaitanya Kulkarni <chiatanya.kulkarni@wdc.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Commit e99e88a9d2b0 renamed a function argument without updating the
corresponding kernel-doc header. Update the kernel-doc header.
Reviewed-by: Chaitanya Kulkarni <chiatanya.kulkarni@wdc.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Fixes: e99e88a9d2b0 ("treewide: setup_timer() -> timer_setup()") # v4.15.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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This patch avoids that the kernel-doc tool warns about this function
header when building with W=1.
Reviewed-by: Chaitanya Kulkarni <chiatanya.kulkarni@wdc.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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This patch avoids that the kernel-doc tool warns about this function
header when building with W=1.
Reviewed-by: Chaitanya Kulkarni <chiatanya.kulkarni@wdc.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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If blk_mq_init_allocated_queue() fails, make sure to free the poll
stat callback struct allocated.
Signed-off-by: Jes Sorensen <jsorensen@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Now a063057d7c73 ("block: Fix a race between request queue removal and
the block cgroup controller") has been reverted, and blkcg_exit_queue()
won't be called in blk_cleanup_queue() any more.
So don't need to protect generic_make_request_checks() with
blk_queue_enter(), then the total mess can be cleaned.
37f9579f4c31 ("blk-mq: Avoid that submitting a bio concurrently with device
removal triggers a crash") is reverted.
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>
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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>
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The following is a description of a hang in blk_mq_freeze_queue_wait().
The hang happens on attempt to freeze a queue while another task does
queue unfreeze.
The root cause is an incorrect sequence of percpu_ref_resurrect() and
percpu_ref_kill() and as a result those two can be swapped:
CPU#0 CPU#1
---------------- -----------------
q1 = blk_mq_init_queue(shared_tags)
q2 = blk_mq_init_queue(shared_tags):
blk_mq_add_queue_tag_set(shared_tags):
blk_mq_update_tag_set_depth(shared_tags):
list_for_each_entry()
blk_mq_freeze_queue(q1)
> percpu_ref_kill()
> blk_mq_freeze_queue_wait()
blk_cleanup_queue(q1)
blk_mq_freeze_queue(q1)
> percpu_ref_kill()
^^^^^^ freeze_depth can't guarantee the order
blk_mq_unfreeze_queue()
> percpu_ref_resurrect()
> blk_mq_freeze_queue_wait()
^^^^^^ Hang here!!!!
This wrong sequence raises kernel warning:
percpu_ref_kill_and_confirm called more than once on blk_queue_usage_counter_release!
WARNING: CPU: 0 PID: 11854 at lib/percpu-refcount.c:336 percpu_ref_kill_and_confirm+0x99/0xb0
But the most unpleasant effect is a hang of a blk_mq_freeze_queue_wait(),
which waits for a zero of a q_usage_counter, which never happens
because percpu-ref was reinited (instead of being killed) and stays in
PERCPU state forever.
How to reproduce:
- "insmod null_blk.ko shared_tags=1 nr_devices=0 queue_mode=2"
- cpu0: python Script.py 0; taskset the corresponding process running on cpu0
- cpu1: python Script.py 1; taskset the corresponding process running on cpu1
Script.py:
------
#!/usr/bin/python3
import os
import sys
while True:
on = "echo 1 > /sys/kernel/config/nullb/%s/power" % sys.argv[1]
off = "echo 0 > /sys/kernel/config/nullb/%s/power" % sys.argv[1]
os.system(on)
os.system(off)
------
This bug was first reported and fixed by Roman, previous discussion:
[1] Message id: 1443287365-4244-7-git-send-email-akinobu.mita@gmail.com
[2] Message id: 1443563240-29306-6-git-send-email-tj@kernel.org
[3] https://patchwork.kernel.org/patch/9268199/
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Roman Pen <roman.penyaev@profitbricks.com>
Signed-off-by: Bob Liu <bob.liu@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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At this point these fields aren't used for anything, so we can remove
them.
Reviewed-by: Ming Lei <ming.lei@redhat.com>
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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We fundamentally do not have a maximum segement size for devices with a
virt boundary. So don't bother checking it, especially given that the
existing checks didn't properly work to start with as we never fully
update the front/back segment size and miss the bi_seg_front_size that
wuld have been required for some cases.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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We currently fail to update the front/back segment size in the bio when
deciding to allow an otherwise gappy segement to a device with a
virt boundary. The reason why this did not cause problems is that
devices with a virt boundary fundamentally don't use segments as we
know it and thus don't care. Make that assumption formal by forcing
an unlimited segement size in this case.
Fixes: f6970f83ef79 ("block: don't check if adjacent bvecs in one bio can be mergeable")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Currently ll_merge_requests_fn, unlike all other merge functions,
reduces nr_phys_segments by one if the last segment of the previous,
and the first segment of the next segement are contigous. While this
seems like a nice solution to avoid building smaller than possible
requests it causes a mismatch between the segments actually present
in the request and those iterated over by the bvec iterators, including
__rq_for_each_bio. This can for example mistrigger the single segment
optimization in the nvme-pci driver, and might lead to mismatching
nr_phys_segments number when recalculating the number of request
when inserting a cloned request.
We could possibly work around this by making the bvec iterators take
the front and back segment size into account, but that would require
moving them from the bio to the bio_iter and spreading this mess
over all users of bvecs. Or we could simply remove this optimization
under the assumption that most users already build good enough bvecs,
and that the bio merge patch never cared about this optimization
either. The latter is what this patch does.
dff824b2aadb ("nvme-pci: optimize mapping of small single segment requests").
Reviewed-by: Ming Lei <ming.lei@redhat.com>
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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Pull more block updates from Jens Axboe:
"This is mainly some late lightnvm changes that came in just before the
merge window, as well as fixes that have been queued up since the
initial pull request was frozen.
This contains:
- lightnvm changes, fixing race conditions, improving memory
utilization, and improving pblk compatability (Chansol, Igor,
Marcin)
- NVMe pull request with minor fixes all over the map (via Christoph)
- remove redundant error print in sata_rcar (Geert)
- struct_size() cleanup (Jackie)
- dasd CONFIG_LBADF warning fix (Ming)
- brd cond_resched() improvement (Mikulas)"
* tag 'for-5.2/block-post-20190516' of git://git.kernel.dk/linux-block: (41 commits)
block/bio-integrity: use struct_size() in kmalloc()
nvme: validate cntlid during controller initialisation
nvme: change locking for the per-subsystem controller list
nvme: trace all async notice events
nvme: fix typos in nvme status code values
nvme-fabrics: remove unused argument
nvme-multipath: avoid crash on invalid subsystem cntlid enumeration
nvme-fc: use separate work queue to avoid warning
nvme-rdma: remove redundant reference between ib_device and tagset
nvme-pci: mark expected switch fall-through
nvme-pci: add known admin effects to augument admin effects log page
nvme-pci: init shadow doorbell after each reset
brd: add cond_resched to brd_free_pages
sata_rcar: Remove ata_host_alloc() error printing
s390/dasd: fix build warning in dasd_eckd_build_cp_raw
lightnvm: pblk: use nvm_rq_to_ppa_list()
lightnvm: pblk: simplify partial read path
lightnvm: do not remove instance under global lock
lightnvm: track inflight target creations
lightnvm: pblk: recover only written metadata
...
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Use the new struct_size() helper to keep code simple.
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Pull block updates from Jens Axboe:
"Nothing major in this series, just fixes and improvements all over the
map. This contains:
- Series of fixes for sed-opal (David, Jonas)
- Fixes and performance tweaks for BFQ (via Paolo)
- Set of fixes for bcache (via Coly)
- Set of fixes for md (via Song)
- Enabling multi-page for passthrough requests (Ming)
- Queue release fix series (Ming)
- Device notification improvements (Martin)
- Propagate underlying device rotational status in loop (Holger)
- Removal of mtip32xx trim support, which has been disabled for years
(Christoph)
- Improvement and cleanup of nvme command handling (Christoph)
- Add block SPDX tags (Christoph)
- Cleanup/hardening of bio/bvec iteration (Christoph)
- A few NVMe pull requests (Christoph)
- Removal of CONFIG_LBDAF (Christoph)
- Various little fixes here and there"
* tag 'for-5.2/block-20190507' of git://git.kernel.dk/linux-block: (164 commits)
block: fix mismerge in bvec_advance
block: don't drain in-progress dispatch in blk_cleanup_queue()
blk-mq: move cancel of hctx->run_work into blk_mq_hw_sysfs_release
blk-mq: always free hctx after request queue is freed
blk-mq: split blk_mq_alloc_and_init_hctx into two parts
blk-mq: free hw queue's resource in hctx's release handler
blk-mq: move cancel of requeue_work into blk_mq_release
blk-mq: grab .q_usage_counter when queuing request from plug code path
block: fix function name in comment
nvmet: protect discovery change log event list iteration
nvme: mark nvme_core_init and nvme_core_exit static
nvme: move command size checks to the core
nvme-fabrics: check more command sizes
nvme-pci: check more command sizes
nvme-pci: remove an unneeded variable initialization
nvme-pci: unquiesce admin queue on shutdown
nvme-pci: shutdown on timeout during deletion
nvme-pci: fix psdt field for single segment sgls
nvme-multipath: don't print ANA group state by default
nvme-multipath: split bios with the ns_head bio_set before submitting
...
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core/kobject updates from Greg KH:
"Here is the "big" set of driver core patches for 5.2-rc1
There are a number of ACPI patches in here as well, as Rafael said
they should go through this tree due to the driver core changes they
required. They have all been acked by the ACPI developers.
There are also a number of small subsystem-specific changes in here,
due to some changes to the kobject core code. Those too have all been
acked by the various subsystem maintainers.
As for content, it's pretty boring outside of the ACPI changes:
- spdx cleanups
- kobject documentation updates
- default attribute groups for kobjects
- other minor kobject/driver core fixes
All have been in linux-next for a while with no reported issues"
* tag 'driver-core-5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (47 commits)
kobject: clean up the kobject add documentation a bit more
kobject: Fix kernel-doc comment first line
kobject: Remove docstring reference to kset
firmware_loader: Fix a typo ("syfs" -> "sysfs")
kobject: fix dereference before null check on kobj
Revert "driver core: platform: Fix the usage of platform device name(pdev->name)"
init/config: Do not select BUILD_BIN2C for IKCONFIG
Provide in-kernel headers to make extending kernel easier
kobject: Improve doc clarity kobject_init_and_add()
kobject: Improve docs for kobject_add/del
driver core: platform: Fix the usage of platform device name(pdev->name)
livepatch: Replace klp_ktype_patch's default_attrs with groups
cpufreq: schedutil: Replace default_attrs field with groups
padata: Replace padata_attr_type default_attrs field with groups
irqdesc: Replace irq_kobj_type's default_attrs field with groups
net-sysfs: Replace ktype default_attrs field with groups
block: Replace all ktype default_attrs with groups
samples/kobject: Replace foo_ktype's default_attrs field with groups
kobject: Add support for default attribute groups to kobj_type
driver core: Postpone DMA tear-down until after devres release for probe failure
...
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Now freeing hw queue resource is moved to hctx's release handler,
we don't need to worry about the race between blk_cleanup_queue and
run queue any more.
So don't drain in-progress dispatch in blk_cleanup_queue().
This is basically revert of c2856ae2f315 ("blk-mq: quiesce queue before
freeing 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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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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In normal queue cleanup path, hctx is released after request queue
is freed, see blk_mq_release().
However, in __blk_mq_update_nr_hw_queues(), hctx may be freed because
of hw queues shrinking. This way is easy to cause use-after-free,
because: one implicit rule is that it is safe to call almost all block
layer APIs if the request queue is alive; and one hctx may be retrieved
by one API, then the hctx can be freed by blk_mq_update_nr_hw_queues();
finally use-after-free is triggered.
Fixes this issue by always freeing hctx after releasing request queue.
If some hctxs are removed in blk_mq_update_nr_hw_queues(), introduce
a per-queue list to hold them, then try to resuse these hctxs if numa
node is matched.
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: 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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Split blk_mq_alloc_and_init_hctx into two parts, and one is
blk_mq_alloc_hctx() for allocating all hctx resources, another
is blk_mq_init_hctx() for initializing hctx, which serves as
counter-part of blk_mq_exit_hctx().
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: 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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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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With holding queue's kobject refcount, it is safe for driver
to schedule requeue. However, blk_mq_kick_requeue_list() may
be called after blk_sync_queue() is done because of concurrent
requeue activities, then requeue work may not be completed when
freeing queue, and kernel oops is triggered.
So moving the cancel of requeue_work into blk_mq_release() for
avoiding race between requeue and freeing 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: Johannes Thumshirn <jthumshirn@suse.de>
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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Just like aio/io_uring, we need to grab 2 refcount for queuing one
request, one is for submission, another is for completion.
If the request isn't queued from plug code path, the refcount grabbed
in generic_make_request() serves for submission. In theroy, this
refcount should have been released after the sumission(async run queue)
is done. blk_freeze_queue() works with blk_sync_queue() together
for avoiding race between cleanup queue and IO submission, given async
run queue activities are canceled because hctx->run_work is scheduled with
the refcount held, so it is fine to not hold the refcount when
running the run queue work function for dispatch IO.
However, if request is staggered into plug list, and finally queued
from plug code path, the refcount in submission side is actually missed.
And we may start to run queue after queue is removed because the queue's
kobject refcount isn't guaranteed to be grabbed in flushing plug list
context, then kernel oops is triggered, see the following race:
blk_mq_flush_plug_list():
blk_mq_sched_insert_requests()
insert requests to sw queue or scheduler queue
blk_mq_run_hw_queue
Because of concurrent run queue, all requests inserted above may be
completed before calling the above blk_mq_run_hw_queue. Then queue can
be freed during the above blk_mq_run_hw_queue().
Fixes the issue by grab .q_usage_counter before calling
blk_mq_sched_insert_requests() in blk_mq_flush_plug_list(). This way is
safe because the queue is absolutely alive before inserting request.
Cc: Dongli Zhang <dongli.zhang@oracle.com>
Cc: James Smart <james.smart@broadcom.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>
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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The comment was out of date.
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Raul E Rangel <rrangel@chromium.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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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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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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All these files have some form of the usual GPLv2 or later boilerplate.
Switch them to use SPDX tags instead.
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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All these files have some form of the usual GPLv2 boilerplate. Switch
them to use SPDX tags instead.
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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Share the bi_size update by moving the done label up, and duplicate
the bv_len update in the two callers to get rid of the bvec_merge
label.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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We are never called with file system pages by defintions for the
passthrough interface, and we also never undo any addition later
these days.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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The same page optimization is a rather odd corner case, which is not
used outside bio.c and which really should not be used outside of bio.c
either - we have better highlevel helpers like the rq/bio mapping
helpers.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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We only have two callers that need the integer loop iterator, and they
can easily maintain it themselves.
Suggested-by: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Acked-by: David Sterba <dsterba@suse.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Acked-by: Coly Li <colyli@suse.de>
Reviewed-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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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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The refcount has been increased for pages retrieved from non-bvec iov iter
via __bio_iov_iter_get_pages(), so don't need to do that again.
Otherwise, IO pages are leaked easily.
Cc: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Fixes: 7321ecbfc7cf ("block: change how we get page references in bio_iov_iter_get_pages")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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bio_add_page() and __bio_add_page() are capable of adding pages into
bio, and now we have at least two such usages alreay:
- __bio_iov_bvec_add_pages()
- nvmet_bdev_execute_rw().
So update comments on these two helpers.
The thing is a bit special for __bio_try_merge_page(), given the caller
needs to know if the new added page is same with the last added page,
then it isn't safe to pass multi-page in case that 'same_page' is true,
so adds warning on potential misuse, and updates comment on
__bio_try_merge_page().
Cc: linux-xfs@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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If the low level driver has no timeout handler, the
/sys/block/<disk>/queue/io_timeout will not be displayed.
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Weiping Zhang <zhangweiping@didiglobal.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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While we generally allow scatterlists to have offsets larger than page
size for an entry, and other subsystems like the crypto code make use of
that, the block layer isn't quite ready for that. Flip the switch back
to avoid them for now, and revisit that decision early in a merge window
once the known offenders are fixed.
Fixes: 8a96a0e40810 ("block: rewrite blk_bvec_map_sg to avoid a nth_page call")
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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commit 2da78092dda "block: Fix dev_t minor allocation lifetime"
specifically moved blk_free_devt(dev->devt) call to part_release()
to avoid reallocating device number before the device is fully
shutdown.
However, it can cause use-after-free on gendisk in get_gendisk().
We use md device as example to show the race scenes:
Process1 Worker Process2
md_free
blkdev_open
del_gendisk
add delete_partition_work_fn() to wq
__blkdev_get
get_gendisk
put_disk
disk_release
kfree(disk)
find part from ext_devt_idr
get_disk_and_module(disk)
cause use after free
delete_partition_work_fn
put_device(part)
part_release
remove part from ext_devt_idr
Before <devt, hd_struct pointer> is removed from ext_devt_idr by
delete_partition_work_fn(), we can find the devt and then access
gendisk by hd_struct pointer. But, if we access the gendisk after
it have been freed, it can cause in use-after-freeon gendisk in
get_gendisk().
We fix this by adding a new helper blk_invalidate_devt() in
delete_partition() and del_gendisk(). It replaces hd_struct
pointer in idr with value 'NULL', and deletes the entry from
idr in part_release() as we do now.
Thanks to Jan Kara for providing the solution and more clear comments
for the code.
Fixes: 2da78092dda1 ("block: Fix dev_t minor allocation lifetime")
Cc: Al Viro <viro@zeniv.linux.org.uk>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Yufen Yu <yuyufen@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Pull in v5.1-rc6 to resolve two conflicts. One is in BFQ, in just a
comment, and is trivial. The other one is a conflict due to a later fix
in the bio multi-page work, and needs a bit more care.
* tag 'v5.1-rc6': (770 commits)
Linux 5.1-rc6
block: make sure that bvec length can't be overflow
block: kill all_q_node in request_queue
x86/cpu/intel: Lower the "ENERGY_PERF_BIAS: Set to normal" message's log priority
coredump: fix race condition between mmget_not_zero()/get_task_mm() and core dumping
mm/kmemleak.c: fix unused-function warning
init: initialize jump labels before command line option parsing
kernel/watchdog_hld.c: hard lockup message should end with a newline
kcov: improve CONFIG_ARCH_HAS_KCOV help text
mm: fix inactive list balancing between NUMA nodes and cgroups
mm/hotplug: treat CMA pages as unmovable
proc: fixup proc-pid-vm test
proc: fix map_files test on F29
mm/vmstat.c: fix /proc/vmstat format for CONFIG_DEBUG_TLBFLUSH=y CONFIG_SMP=n
mm/memory_hotplug: do not unlock after failing to take the device_hotplug_lock
mm: swapoff: shmem_unuse() stop eviction without igrab()
mm: swapoff: take notice of completion sooner
mm: swapoff: remove too limiting SWAP_UNUSE_MAX_TRIES
mm: swapoff: shmem_find_swap_entries() filter out other types
slab: store tagged freelist for off-slab slabmgmt
...
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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A previous commit moved the shallow depth and BFQ depth map calculations
to be done at init time, moving it outside of the hotter IO path. This
potentially causes hangs if the users changes the depth of the scheduler
map, by writing to the 'nr_requests' sysfs file for that device.
Add a blk-mq-sched hook that allows blk-mq to inform the scheduler if
the depth changes, so that the scheduler can update its internal state.
Tested-by: Kai Krakow <kai@kaishome.de>
Reported-by: Paolo Valente <paolo.valente@linaro.org>
Fixes: f0635b8a416e ("bfq: calculate shallow depths at init time")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Drivers now report to the block layer if they support media change
events. If this is not the case, there's no need to allocate the event
structure, and all event handling code can effectively be skipped. This
simplifies code flow in particular for non-removable sd devices.
This effectively reverts commit 75e3f3ee3c64 ("block: always allocate
genhd->ev if check_events is implemented").
The sysfs files for the events are kept in place even if no events are
supported, as user space may rely on them being present. The only
difference is that an error code is now returned if the user tries to
set poll_msecs.
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin Wilck <mwilck@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Currently, an empty disk->events field tells the block layer not to
forward media change events to user space. This was done in commit
7c88a168da80 ("block: don't propagate unlisted DISK_EVENTs to userland")
in order to avoid events from "fringe" drivers to be forwarded to user
space. By doing so, the block layer lost the information which events
were supported by a particular block device, and most importantly,
whether or not a given device supports media change events at all.
Prepare for not interpreting the "events" field this way in the future
any more. This is done by adding an additional field "event_flags" to
struct gendisk, and two flag bits that can be set to have the device
treated like one that had the "events" field set to a non-zero value
before. This applies only to the sd and sr drivers, which are changed to
set the new flags.
The new flags are DISK_EVENT_FLAG_POLL to enforce polling of the device
for synchronous events, and DISK_EVENT_FLAG_UEVENT to tell the
blocklayer to generate udev events from kernel events.
In order to add the event_flags field to struct gendisk, the events
field is converted to an "unsigned short"; it doesn't need to hold
values bigger than 2 anyway.
This patch doesn't change behavior.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin Wilck <mwilck@suse.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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