Commit Graph

6605 Commits

Author SHA1 Message Date
Ye Bin
90b0296ece block: fix crash in 'blk_mq_elv_switch_none'
Syzbot found the following issue:
general protection fault, probably for non-canonical address 0xdffffc000000001d: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x00000000000000e8-0x00000000000000ef]
CPU: 0 PID: 5234 Comm: syz-executor931 Not tainted 6.1.0-rc3-next-20221102-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
RIP: 0010:__elevator_get block/elevator.h:94 [inline]
RIP: 0010:blk_mq_elv_switch_none block/blk-mq.c:4593 [inline]
RIP: 0010:__blk_mq_update_nr_hw_queues block/blk-mq.c:4658 [inline]
RIP: 0010:blk_mq_update_nr_hw_queues+0x304/0xe40 block/blk-mq.c:4709
RSP: 0018:ffffc90003cdfc08 EFLAGS: 00010206
RAX: 0000000000000000 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 000000000000001d RSI: 0000000000000002 RDI: 00000000000000e8
RBP: ffff88801dbd0000 R08: ffff888027c89398 R09: ffffffff8de2e517
R10: fffffbfff1bc5ca2 R11: 0000000000000000 R12: ffffc90003cdfc70
R13: ffff88801dbd0008 R14: ffff88801dbd03f8 R15: ffff888027c89380
FS:  0000555557259300(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000005d84c8 CR3: 000000007a7cb000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 nbd_start_device+0x153/0xc30 drivers/block/nbd.c:1355
 nbd_start_device_ioctl drivers/block/nbd.c:1405 [inline]
 __nbd_ioctl drivers/block/nbd.c:1481 [inline]
 nbd_ioctl+0x5a1/0xbd0 drivers/block/nbd.c:1521
 blkdev_ioctl+0x36e/0x800 block/ioctl.c:614
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl fs/ioctl.c:856 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

As after dd6f7f17bf commit move '__elevator_get(qe->type)' before set
'qe->type', so will lead to access wild pointer.
To solve above issue get 'qe->type' after set 'qe->type'.

Reported-by: syzbot+746a4eece09f86bc39d7@syzkaller.appspotmail.com
Fixes:dd6f7f17bf58("block: add proper helpers for elevator_type module refcount management")
Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221107033956.3276891-1-yebin@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-24 06:58:11 -07:00
Damien Le Moal
015d02f485 block: mq-deadline: Do not break sequential write streams to zoned HDDs
mq-deadline ensures an in order dispatching of write requests to zoned
block devices using a per zone lock (a bit). This implies that for any
purely sequential write workload, the drive is exercised most of the
time at a maximum queue depth of one.

However, when such sequential write workload crosses a zone boundary
(when sequentially writing multiple contiguous zones), zone write
locking may prevent the last write to one zone to be issued (as the
previous write is still being executed) but allow the first write to the
following zone to be issued (as that zone is not yet being writen and
not locked). This result in an out of order delivery of the sequential
write commands to the device every time a zone boundary is crossed.

While such behavior does not break the sequential write constraint of
zoned block devices (and does not generate any write error), some zoned
hard-disks react badly to seeing these out of order writes, resulting in
lower write throughput.

This problem can be addressed by always dispatching the first request
of a stream of sequential write requests, regardless of the zones
targeted by these sequential writes. To do so, the function
deadline_skip_seq_writes() is introduced and used in
deadline_next_request() to select the next write command to issue if the
target device is an HDD (blk_queue_nonrot() being false).
deadline_fifo_request() is modified using the new
deadline_earlier_request() and deadline_is_seq_write() helpers to ignore
requests in the fifo list that have a preceding request in lba order
that is sequential.

With this fix, a sequential write workload executed with the following
fio command:

fio  --name=seq-write --filename=/dev/sda --zonemode=zbd --direct=1 \
     --size=68719476736  --ioengine=libaio --iodepth=32 --rw=write \
     --bs=65536

results in an increase from 225 MB/s to 250 MB/s of the write throughput
of an SMR HDD (11% increase).

Cc: <stable@vger.kernel.org>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20221124021208.242541-3-damien.lemoal@opensource.wdc.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-24 06:29:36 -07:00
Damien Le Moal
2820e5d082 block: mq-deadline: Fix dd_finish_request() for zoned devices
dd_finish_request() tests if the per prio fifo_list is not empty to
determine if request dispatching must be restarted for handling blocked
write requests to zoned devices with a call to
blk_mq_sched_mark_restart_hctx(). While simple, this implementation has
2 problems:

1) Only the priority level of the completed request is considered.
   However, writes to a zone may be blocked due to other writes to the
   same zone using a different priority level. While this is unlikely to
   happen in practice, as writing a zone with different IO priorirites
   does not make sense, nothing in the code prevents this from
   happening.
2) The use of list_empty() is dangerous as dd_finish_request() does not
   take dd->lock and may run concurrently with the insert and dispatch
   code.

Fix these 2 problems by testing the write fifo list of all priority
levels using the new helper dd_has_write_work(), and by testing each
fifo list using list_empty_careful().

Fixes: c807ab520f ("block/mq-deadline: Add I/O priority support")
Cc: <stable@vger.kernel.org>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20221124021208.242541-2-damien.lemoal@opensource.wdc.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-24 06:29:36 -07:00
Bart Van Assche
85168d416e blk-crypto: Add a missing include directive
Allow the compiler to verify consistency of function declarations and
function definitions. This patch fixes the following sparse errors:

block/blk-crypto-profile.c:241:14: error: no previous prototype for ‘blk_crypto_get_keyslot’ [-Werror=missing-prototypes]
  241 | blk_status_t blk_crypto_get_keyslot(struct blk_crypto_profile *profile,
      |              ^~~~~~~~~~~~~~~~~~~~~~
block/blk-crypto-profile.c:318:6: error: no previous prototype for ‘blk_crypto_put_keyslot’ [-Werror=missing-prototypes]
  318 | void blk_crypto_put_keyslot(struct blk_crypto_keyslot *slot)
      |      ^~~~~~~~~~~~~~~~~~~~~~
block/blk-crypto-profile.c:344:6: error: no previous prototype for ‘__blk_crypto_cfg_supported’ [-Werror=missing-prototypes]
  344 | bool __blk_crypto_cfg_supported(struct blk_crypto_profile *profile,
      |      ^~~~~~~~~~~~~~~~~~~~~~~~~~
block/blk-crypto-profile.c:373:5: error: no previous prototype for ‘__blk_crypto_evict_key’ [-Werror=missing-prototypes]
  373 | int __blk_crypto_evict_key(struct blk_crypto_profile *profile,
      |     ^~~~~~~~~~~~~~~~~~~~~~

Cc: Eric Biggers <ebiggers@google.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20221123172923.434339-1-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-23 10:38:54 -07:00
Jinlong Chen
4284354758 elevator: remove an outdated comment in elevator_change
mq is no longer a special case.

Signed-off-by: Jinlong Chen <nickyc975@zju.edu.cn>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/cbf47824fc726440371e74c867bf635ae1b671a3.1669126766.git.nickyc975@zju.edu.cn
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-23 06:48:20 -07:00
Jinlong Chen
f69b5e8f35 elevator: update the document of elevator_match
elevator_match does not care about elevator_features any more. Remove
related descriptions from its document.

Fixes: ffb86425ee ("block: don't check for required features in elevator_match")
Signed-off-by: Jinlong Chen <nickyc975@zju.edu.cn>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/a58424555202c07a9ccf7f60c3ad7e247da09e25.1669126766.git.nickyc975@zju.edu.cn
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-23 06:48:20 -07:00
Jinlong Chen
e0cca8bc9c elevator: printk a warning if switching to a new io scheduler fails
printk a warning to indicate that the io scheduler has been set to none
if switching to a new io scheduler fails.

Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jinlong Chen <nickyc975@zju.edu.cn>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/d51ed0fb457db7a4f9cbb0dbce36d534e22be457.1669126766.git.nickyc975@zju.edu.cn
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-23 06:48:08 -07:00
Jinlong Chen
ac1171bd2c elevator: update the document of elevator_switch
We no longer support falling back to the old io scheduler if switching to
the new one fails. Update the document to indicate that.

Fixes: a1ce35fa49 ("block: remove dead elevator code")
Signed-off-by: Jinlong Chen <nickyc975@zju.edu.cn>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/94250961689ba7d2e67a7d9e7995a11166fedb31.1669126766.git.nickyc975@zju.edu.cn
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-23 06:47:46 -07:00
Christoph Hellwig
22c17e279a blk-mq: fix queue reference leak on blk_mq_alloc_disk_for_queue failure
Drop the request queue reference just acquired when __alloc_disk_node
failed.

Fixes: 6f8191fdf4 ("block: simplify disk shutdown")
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Link: https://lore.kernel.org/r/20221122072753.426077-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-22 15:58:08 -07:00
Shin'ichiro Kawasaki
d4b2e0d433 block: fix missing nr_hw_queues update in blk_mq_realloc_tag_set_tags
The commit ee9d55210c ("blk-mq: simplify blk_mq_realloc_tag_set_tags")
cleaned up the function blk_mq_realloc_tag_set_tags. After this change,
the function does not update nr_hw_queues of struct blk_mq_tag_set when
new nr_hw_queues value is smaller than original. This results in failure
of queue number change of block devices. To avoid the failure, add the
missing nr_hw_queues update.

Fixes: ee9d55210c ("blk-mq: simplify blk_mq_realloc_tag_set_tags")
Reported-by: Chaitanya Kulkarni <chaitanyak@nvidia.com>
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Link: https://lore.kernel.org/linux-block/20221118140640.featvt3fxktfquwh@shindev/
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221122084917.2034220-1-shinichiro.kawasaki@wdc.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-22 06:10:54 -07:00
Christoph Hellwig
3569788c08 blk-crypto: move internal only declarations to blk-crypto-internal.h
blk_crypto_get_keyslot, blk_crypto_put_keyslot, __blk_crypto_evict_key
and __blk_crypto_cfg_supported are only used internally by the
blk-crypto code, so move the out of blk-crypto-profile.h, which is
included by drivers that supply blk-crypto functionality.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20221114042944.1009870-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-21 11:39:05 -07:00
Christoph Hellwig
6715c98b6c blk-crypto: add a blk_crypto_config_supported_natively helper
Add a blk_crypto_config_supported_natively helper that wraps
__blk_crypto_cfg_supported to retrieve the crypto_profile from the
request queue.  With this fscrypt can stop including
blk-crypto-profile.h and rely on the public consumer interface in
blk-crypto.h.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20221114042944.1009870-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-21 11:39:05 -07:00
Christoph Hellwig
fce3caea0f blk-crypto: don't use struct request_queue for public interfaces
Switch all public blk-crypto interfaces to use struct block_device
arguments to specify the device they operate on instead of th
request_queue, which is a block layer implementation detail.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20221114042944.1009870-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-21 11:39:05 -07:00
Linus Torvalds
f4408c3dfc block-6.1-2022-11-18
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Merge tag 'block-6.1-2022-11-18' of git://git.kernel.dk/linux

Pull block fixes from Jens Axboe:

 - NVMe pull request via Christoph:
      - Two more bogus nid quirks (Bean Huo, Tiago Dias Ferreira)
      - Memory leak fix in nvmet (Sagi Grimberg)

 - Regression fix for block cgroups pinning the wrong blkcg, causing
   leaks of cgroups and blkcgs (Chris)

 - UAF fix for drbd setup error handling (Dan)

 - Fix DMA alignment propagation in DM (Keith)

* tag 'block-6.1-2022-11-18' of git://git.kernel.dk/linux:
  dm-log-writes: set dma_alignment limit in io_hints
  dm-integrity: set dma_alignment limit in io_hints
  block: make blk_set_default_limits() private
  dm-crypt: provide dma_alignment limit in io_hints
  block: make dma_alignment a stacking queue_limit
  nvmet: fix a memory leak in nvmet_auth_set_key
  nvme-pci: add NVME_QUIRK_BOGUS_NID for Netac NV7000
  drbd: use after free in drbd_create_device()
  nvme-pci: add NVME_QUIRK_BOGUS_NID for Micron Nitro
  blk-cgroup: properly pin the parent in blkcg_css_online
2022-11-18 13:59:45 -08:00
Waiman Long
dae590a6c9 blk-cgroup: Flush stats at blkgs destruction path
As noted by Michal, the blkg_iostat_set's in the lockless list
hold reference to blkg's to protect against their removal. Those
blkg's hold reference to blkcg. When a cgroup is being destroyed,
cgroup_rstat_flush() is only called at css_release_work_fn() which is
called when the blkcg reference count reaches 0. This circular dependency
will prevent blkcg from being freed until some other events cause
cgroup_rstat_flush() to be called to flush out the pending blkcg stats.

To prevent this delayed blkcg removal, add a new cgroup_rstat_css_flush()
function to flush stats for a given css and cpu and call it at the blkgs
destruction path, blkcg_destroy_blkgs(), whenever there are still some
pending stats to be flushed. This will ensure that blkcg reference
count can reach 0 ASAP.

Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20221105005902.407297-4-longman@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-16 16:58:44 -07:00
Waiman Long
3b8cc62987 blk-cgroup: Optimize blkcg_rstat_flush()
For a system with many CPUs and block devices, the time to do
blkcg_rstat_flush() from cgroup_rstat_flush() can be rather long. It
can be especially problematic as interrupt is disabled during the flush.
It was reported that it might take seconds to complete in some extreme
cases leading to hard lockup messages.

As it is likely that not all the percpu blkg_iostat_set's has been
updated since the last flush, those stale blkg_iostat_set's don't need
to be flushed in this case. This patch optimizes blkcg_rstat_flush()
by keeping a lockless list of recently updated blkg_iostat_set's in a
newly added percpu blkcg->lhead pointer.

The blkg_iostat_set is added to a lockless list on the update side
in blk_cgroup_bio_start(). It is removed from the lockless list when
flushed in blkcg_rstat_flush(). Due to racing, it is possible that
blk_iostat_set's in the lockless list may have no new IO stats to be
flushed, but that is OK.

To protect against destruction of blkg, a percpu reference is gotten
when putting into the lockless list and put back when removed.

When booting up an instrumented test kernel with this patch on a
2-socket 96-thread system with cgroup v2, out of the 2051 calls to
cgroup_rstat_flush() after bootup, 1788 of the calls were exited
immediately because of empty lockless list. After an all-cpu kernel
build, the ratio became 6295424/6340513. That was more than 99%.

Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20221105005902.407297-3-longman@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-16 16:58:44 -07:00
Waiman Long
b5a9adcbd5 blk-cgroup: Return -ENOMEM directly in blkcg_css_alloc() error path
For blkcg_css_alloc(), the only error that will be returned is -ENOMEM.
Simplify error handling code by returning this error directly instead
of setting an intermediate "ret" variable.

Signed-off-by: Waiman Long <longman@redhat.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20221105005902.407297-2-longman@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-16 16:58:44 -07:00
Keith Busch
b3228254bb block: make blk_set_default_limits() private
There are no external users of this function.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221110184501.2451620-4-kbusch@meta.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-16 15:58:11 -07:00
Keith Busch
c964d62f5c block: make dma_alignment a stacking queue_limit
Device mappers had always been getting the default 511 dma mask, but
the underlying device might have a larger alignment requirement. Since
this value is used to determine alloweable direct-io alignment, this
needs to be a stackable limit.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221110184501.2451620-2-kbusch@meta.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-16 15:58:11 -07:00
Yu Kuai
077a403354 block: don't allow a disk link holder to itself
After creating a dm device, then user can reload such dm with itself,
and dead loop will be triggered because dm keep looking up to itself.

Test procedures:

1) dmsetup create test --table "xxx sda", assume dm-0 is created
2) dmsetup suspend test
3) dmsetup reload test --table "xxx dm-0"
4) dmsetup resume test

Test result:

BUG: TASK stack guard page was hit at 00000000736a261f (stack is 000000008d12c88d..00000000c8dd82d5)
stack guard page: 0000 [#1] PREEMPT SMP
CPU: 29 PID: 946 Comm: systemd-udevd Not tainted 6.1.0-rc3-next-20221101-00006-g17640ca3b0ee #1295
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014
RIP: 0010:dm_prepare_ioctl+0xf/0x1e0
Code: da 48 83 05 4a 7c 99 0b 01 41 89 c4 eb cd e8 b8 1f 40 00 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 41 57 48 83 05 a1 5a 99 0b 01 <41> 56 49 89 d6 41 55 4c 8d af 90 02 00 00 9
RSP: 0018:ffffc90002090000 EFLAGS: 00010206
RAX: ffff8881049d6800 RBX: ffff88817e589000 RCX: 0000000000000000
RDX: ffffc90002090010 RSI: ffffc9000209001c RDI: ffff88817e589000
RBP: 00000000484a101d R08: 0000000000000000 R09: 0000000000000007
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000005331
R13: 0000000000005331 R14: 0000000000000000 R15: 0000000000000000
FS:  00007fddf9609200(0000) GS:ffff889fbfd40000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffc9000208fff8 CR3: 0000000179043000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 dm_blk_ioctl+0x50/0x1c0
 ? dm_prepare_ioctl+0xe0/0x1e0
 dm_blk_ioctl+0x88/0x1c0
 dm_blk_ioctl+0x88/0x1c0
 ......(a lot of same lines)
 dm_blk_ioctl+0x88/0x1c0
 dm_blk_ioctl+0x88/0x1c0
 blkdev_ioctl+0x184/0x3e0
 __x64_sys_ioctl+0xa3/0x110
 do_syscall_64+0x35/0x80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fddf7306577
Code: b3 66 90 48 8b 05 11 89 2c 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d e1 88 8
RSP: 002b:00007ffd0b2ec318 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00005634ef478320 RCX: 00007fddf7306577
RDX: 0000000000000000 RSI: 0000000000005331 RDI: 0000000000000007
RBP: 0000000000000007 R08: 00005634ef4843e0 R09: 0000000000000080
R10: 00007fddf75cfb38 R11: 0000000000000246 R12: 00000000030d4000
R13: 0000000000000000 R14: 0000000000000000 R15: 00005634ef48b800
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:dm_prepare_ioctl+0xf/0x1e0
Code: da 48 83 05 4a 7c 99 0b 01 41 89 c4 eb cd e8 b8 1f 40 00 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 41 57 48 83 05 a1 5a 99 0b 01 <41> 56 49 89 d6 41 55 4c 8d af 90 02 00 00 9
RSP: 0018:ffffc90002090000 EFLAGS: 00010206
RAX: ffff8881049d6800 RBX: ffff88817e589000 RCX: 0000000000000000
RDX: ffffc90002090010 RSI: ffffc9000209001c RDI: ffff88817e589000
RBP: 00000000484a101d R08: 0000000000000000 R09: 0000000000000007
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000005331
R13: 0000000000005331 R14: 0000000000000000 R15: 0000000000000000
FS:  00007fddf9609200(0000) GS:ffff889fbfd40000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffc9000208fff8 CR3: 0000000179043000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Kernel panic - not syncing: Fatal exception in interrupt
Kernel Offset: disabled
---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---

Fix the problem by forbidding a disk to create link to itself.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221115141054.1051801-11-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-16 15:19:56 -07:00
Yu Kuai
3b3449c1e6 block: store the holder kobject in bd_holder_disk
We hold a reference to the holder kobject for each bd_holder_disk,
so to make the code a bit more robust, use a reference to it instead
of the block_device.  As long as no one clears ->bd_holder_dir in
before freeing the disk, this isn't strictly required, but it does
make the code more clear and more robust.

Orignally-From: Christoph Hellwig <hch@lst.de>
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221115141054.1051801-10-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-16 15:19:56 -07:00
Yu Kuai
62f535e1f0 block: fix use after free for bd_holder_dir
Currently, the caller of bd_link_disk_holer() get 'bdev' by
blkdev_get_by_dev(), which will look up 'bdev' by inode number 'dev'.
Howerver, it's possible that del_gendisk() can be called currently, and
'bd_holder_dir' can be freed before bd_link_disk_holer() access it, thus
use after free is triggered.

t1:				t2:
bdev = blkdev_get_by_dev
				del_gendisk
				 kobject_put(bd_holder_dir)
				  kobject_free()
bd_link_disk_holder

Fix the problem by checking disk is still live and grabbing a reference
to 'bd_holder_dir' first in bd_link_disk_holder().

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221115141054.1051801-9-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-16 15:19:56 -07:00
Christoph Hellwig
7abc077788 block: remove delayed holder registration
Now that dm has been fixed to track of holder registrations before
add_disk, the somewhat buggy block layer code can be safely removed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20221115141054.1051801-8-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-16 15:19:56 -07:00
Christoph Hellwig
d90db3b1c8 block: clear ->slave_dir when dropping the main slave_dir reference
Zero out the pointer to ->slave_dir so that the holder code doesn't
incorrectly treat the object as alive when add_disk failed or after
del_gendisk was called.

Fixes: 89f871af1b ("dm: delay registering the gendisk")
Reported-by: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Mike Snitzer <snitzer@kernel.org>
Link: https://lore.kernel.org/r/20221115141054.1051801-2-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-16 15:19:53 -07:00
Christoph Hellwig
470373e888 block: remove blkdev_writepages
While the block device code should switch to implementing
->writepages instead of ->writepage eventually, the current
implementation is entirely pointless as it does the same looping over
->writepage as the generic code if no ->writepages is present.

Remove blkdev_writepages so that we can eventually unexport
generic_writepages.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221116132035.2192924-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-16 11:32:53 -07:00
Pavel Begunkov
42b2b2fb6e bio: shrink max number of pcpu cached bios
The downside of the bio pcpu cache is that bios of a cpu will be never
freed unless there is new I/O issued from that cpu. We currently keep
max 512 bios, which feels too much, half it.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/bc198e8efb27d8c740d80c8ce477432729075096.1667384020.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-16 09:44:26 -07:00
Pavel Begunkov
b99182c501 bio: add pcpu caching for non-polling bio_put
This patch extends REQ_ALLOC_CACHE to IRQ completions, whenever
currently it's only limited to iopoll. Instead of guarding the list with
irq toggling on alloc, which is expensive, it keeps an additional
irq-safe list from which bios are spliced in batches to ammortise
overhead. On the put side it toggles irqs, but in many cases they're
already disabled and so cheap.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/c2306de96b900ab9264f4428ec37768ddcf0da36.1667384020.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-16 09:44:26 -07:00
Pavel Begunkov
f25cf75a45 bio: split pcpu cache part of bio_put into a helper
Extract a helper out of bio_put for recycling into percpu caches.
It's a preparation patch without functional changes.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/e97ab2026a89098ee1bfdd09bcb9451fced95f87.1667384020.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-16 09:44:26 -07:00
Pavel Begunkov
759aa12f19 bio: don't rob starving biosets of bios
Biosets keep a mempool, so as long as requests complete we can always
can allocate and have forward progress. Percpu bio caches break that
assumptions as we may complete into the cache of one CPU and after try
and fail to allocate with another CPU. We also can't grab from another
CPU's cache without tricky sync.

If we're allocating with a bio while the mempool is undersaturated,
remove REQ_ALLOC_CACHE flag, so on put it will go straight to mempool.
It might try to free into mempool more requests than required, but
assuming than there is no memory starvation in the system it'll
stabilise and never hit that path.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/aa150caf9c263fa92269e86d7826cc8fa65f38de.1667384020.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-16 09:44:26 -07:00
Chris Mason
d7dbd43f4a blk-cgroup: properly pin the parent in blkcg_css_online
blkcg_css_online is supposed to pin the blkcg of the parent, but
397c9f46ee refactored things and along the way, changed it to pin the
css instead.  This results in extra pins, and we end up leaking blkcgs
and cgroups.

Fixes: 397c9f46ee ("blk-cgroup: move blkcg_{pin,unpin}_online out of line")
Signed-off-by: Chris Mason <clm@fb.com>
Spotted-by: Rik van Riel <riel@surriel.com>
Cc: <stable@vger.kernel.org> # v5.19+
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Link: https://lore.kernel.org/r/20221114181930.2093706-1-clm@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-14 12:13:19 -07:00
Linus Torvalds
b0b6e2c9d3 block-6.1-2022-11-11
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Merge tag 'block-6.1-2022-11-11' of git://git.kernel.dk/linux

Pull block fixes from Jens Axboe:

 - NVMe pull request via Christoph:
        - Quiet user passthrough command errors (Keith Busch)
        - Fix memory leak in nvmet_subsys_attr_model_store_locked
        - Fix a memory leak in nvmet-auth (Sagi Grimberg)

 - Fix a potential NULL point deref in bfq (Yu)

 - Allocate command/response buffers separately for DMA for sed-opal,
   rather than rely on embedded alignment (Serge)

* tag 'block-6.1-2022-11-11' of git://git.kernel.dk/linux:
  nvmet: fix a memory leak
  nvmet: fix memory leak in nvmet_subsys_attr_model_store_locked
  nvme: quiet user passthrough command errors
  block: sed-opal: kmalloc the cmd/resp buffers
  block, bfq: fix null pointer dereference in bfq_bio_bfqg()
2022-11-11 14:08:30 -08:00
Christoph Hellwig
ee9d55210c blk-mq: simplify blk_mq_realloc_tag_set_tags
Use set->nr_hw_queues for the current number of tags, and remove the
duplicate set->nr_hw_queues update in the caller.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20221109100811.2413423-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-10 11:18:09 -07:00
Christoph Hellwig
5ee20298ff blk-mq: remove blk_mq_alloc_tag_set_tags
There is no point in trying to share any code with the realloc case when
all that is needed by the initial tagset allocation is a simple
kcalloc_node.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20221109100811.2413423-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-10 11:18:09 -07:00
Khazhismel Kumykov
99771d73ff bfq: ignore oom_bfqq in bfq_check_waker
oom_bfqq is just a fallback bfqq, so shouldn't be used with waker
detection.

Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Khazhismel Kumykov <khazhy@google.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20221108181030.1611703-2-khazhy@google.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-09 12:42:26 -07:00
Khazhismel Kumykov
a1795c2ccb bfq: fix waker_bfqq inconsistency crash
This fixes crashes in bfq_add_bfqq_busy due to waker_bfqq being NULL,
but woken_list_node still being hashed. This would happen when
bfq_init_rq() expects a brand new allocated queue to be returned from
bfq_get_bfqq_handle_split() and unconditionally updates waker_bfqq
without resetting woken_list_node. Since we can always return oom_bfqq
when attempting to allocate, we cannot assume waker_bfqq starts as NULL.

Avoid setting woken_bfqq for oom_bfqq entirely, as it's not useful.

Crashes would have a stacktrace like:
[160595.656560]  bfq_add_bfqq_busy+0x110/0x1ec
[160595.661142]  bfq_add_request+0x6bc/0x980
[160595.666602]  bfq_insert_request+0x8ec/0x1240
[160595.671762]  bfq_insert_requests+0x58/0x9c
[160595.676420]  blk_mq_sched_insert_request+0x11c/0x198
[160595.682107]  blk_mq_submit_bio+0x270/0x62c
[160595.686759]  __submit_bio_noacct_mq+0xec/0x178
[160595.691926]  submit_bio+0x120/0x184
[160595.695990]  ext4_mpage_readpages+0x77c/0x7c8
[160595.701026]  ext4_readpage+0x60/0xb0
[160595.705158]  filemap_read_page+0x54/0x114
[160595.711961]  filemap_fault+0x228/0x5f4
[160595.716272]  do_read_fault+0xe0/0x1f0
[160595.720487]  do_fault+0x40/0x1c8

Tested by injecting random failures into bfq_get_queue, crashes go away
completely.

Fixes: 8ef3fc3a04 ("block, bfq: make shared queues inherit wakers")
Signed-off-by: Khazhismel Kumykov <khazhy@google.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20221108181030.1611703-1-khazhy@google.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-09 12:42:26 -07:00
Logan Gunthorpe
7ee4ccf574 block: set FOLL_PCI_P2PDMA in bio_map_user_iov()
When a bio's queue supports PCI P2PDMA, set FOLL_PCI_P2PDMA for
iov_iter_get_pages_flags(). This allows PCI P2PDMA pages to be
passed from userspace and enables the NVMe passthru requests to
use P2PDMA pages.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20221021174116.7200-8-logang@deltatee.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-09 11:29:21 -07:00
Logan Gunthorpe
5e3e3f2e15 block: set FOLL_PCI_P2PDMA in __bio_iov_iter_get_pages()
When a bio's queue supports PCI P2PDMA, set FOLL_PCI_P2PDMA for
iov_iter_get_pages_flags(). This allows PCI P2PDMA pages to be passed
from userspace and enables the O_DIRECT path in iomap based filesystems
and direct to block devices.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20221021174116.7200-7-logang@deltatee.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-09 11:29:21 -07:00
Logan Gunthorpe
49580e6907 block: add check when merging zone device pages
Consecutive zone device pages should not be merged into the same sgl
or bvec segment with other types of pages or if they belong to different
pgmaps. Otherwise getting the pgmap of a given segment is not possible
without scanning the entire segment. This helper returns true either if
both pages are not zone device pages or both pages are zone device
pages with the same pgmap.

Add a helper to determine if zone device pages are mergeable and use
this helper in page_is_mergeable().

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20221021174116.7200-5-logang@deltatee.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-09 11:29:21 -07:00
Serge Semin
f829230dd5 block: sed-opal: kmalloc the cmd/resp buffers
In accordance with [1] the DMA-able memory buffers must be
cacheline-aligned otherwise the cache writing-back and invalidation
performed during the mapping may cause the adjacent data being lost. It's
specifically required for the DMA-noncoherent platforms [2]. Seeing the
opal_dev.{cmd,resp} buffers are implicitly used for DMAs in the NVME and
SCSI/SD drivers in framework of the nvme_sec_submit() and sd_sec_submit()
methods respectively they must be cacheline-aligned to prevent the denoted
problem. One of the option to guarantee that is to kmalloc the buffers
[2]. Let's explicitly allocate them then instead of embedding into the
opal_dev structure instance.

Note this fix was inspired by the commit c94b7f9bab ("nvme-hwmon:
kmalloc the NVME SMART log buffer").

[1] Documentation/core-api/dma-api.rst
[2] Documentation/core-api/dma-api-howto.rst

Fixes: 455a7b238c ("block: Add Sed-opal library")
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221107203944.31686-1-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-08 07:14:35 -07:00
Yu Kuai
f02be9002c block, bfq: fix null pointer dereference in bfq_bio_bfqg()
Out test found a following problem in kernel 5.10, and the same problem
should exist in mainline:

BUG: kernel NULL pointer dereference, address: 0000000000000094
PGD 0 P4D 0
Oops: 0000 [#1] SMP
CPU: 7 PID: 155 Comm: kworker/7:1 Not tainted 5.10.0-01932-g19e0ace2ca1d-dirty 4
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-b4
Workqueue: kthrotld blk_throtl_dispatch_work_fn
RIP: 0010:bfq_bio_bfqg+0x52/0xc0
Code: 94 00 00 00 00 75 2e 48 8b 40 30 48 83 05 35 06 c8 0b 01 48 85 c0 74 3d 4b
RSP: 0018:ffffc90001a1fba0 EFLAGS: 00010002
RAX: ffff888100d60400 RBX: ffff8881132e7000 RCX: 0000000000000000
RDX: 0000000000000017 RSI: ffff888103580a18 RDI: ffff888103580a18
RBP: ffff8881132e7000 R08: 0000000000000000 R09: ffffc90001a1fe10
R10: 0000000000000a20 R11: 0000000000034320 R12: 0000000000000000
R13: ffff888103580a18 R14: ffff888114447000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff88881fdc0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000094 CR3: 0000000100cdb000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 bfq_bic_update_cgroup+0x3c/0x350
 ? ioc_create_icq+0x42/0x270
 bfq_init_rq+0xfd/0x1060
 bfq_insert_requests+0x20f/0x1cc0
 ? ioc_create_icq+0x122/0x270
 blk_mq_sched_insert_requests+0x86/0x1d0
 blk_mq_flush_plug_list+0x193/0x2a0
 blk_flush_plug_list+0x127/0x170
 blk_finish_plug+0x31/0x50
 blk_throtl_dispatch_work_fn+0x151/0x190
 process_one_work+0x27c/0x5f0
 worker_thread+0x28b/0x6b0
 ? rescuer_thread+0x590/0x590
 kthread+0x153/0x1b0
 ? kthread_flush_work+0x170/0x170
 ret_from_fork+0x1f/0x30
Modules linked in:
CR2: 0000000000000094
---[ end trace e2e59ac014314547 ]---
RIP: 0010:bfq_bio_bfqg+0x52/0xc0
Code: 94 00 00 00 00 75 2e 48 8b 40 30 48 83 05 35 06 c8 0b 01 48 85 c0 74 3d 4b
RSP: 0018:ffffc90001a1fba0 EFLAGS: 00010002
RAX: ffff888100d60400 RBX: ffff8881132e7000 RCX: 0000000000000000
RDX: 0000000000000017 RSI: ffff888103580a18 RDI: ffff888103580a18
RBP: ffff8881132e7000 R08: 0000000000000000 R09: ffffc90001a1fe10
R10: 0000000000000a20 R11: 0000000000034320 R12: 0000000000000000
R13: ffff888103580a18 R14: ffff888114447000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff88881fdc0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000094 CR3: 0000000100cdb000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Root cause is quite complex:

1) use bfq elevator for the test device.
2) create a cgroup CG
3) config blk throtl in CG

   blkg_conf_prep
    blkg_create

4) create a thread T1 and issue async io in CG:

   bio_init
    bio_associate_blkg
   ...
   submit_bio
    submit_bio_noacct
     blk_throtl_bio -> io is throttled
     // io submit is done

5) switch elevator:

   bfq_exit_queue
    blkcg_deactivate_policy
     list_for_each_entry(blkg, &q->blkg_list, q_node)
      blkg->pd[] = NULL
      // bfq policy is removed

5) thread t1 exist, then remove the cgroup CG:

   blkcg_unpin_online
    blkcg_destroy_blkgs
     blkg_destroy
      list_del_init(&blkg->q_node)
      // blkg is removed from queue list

6) switch elevator back to bfq

 bfq_init_queue
  bfq_create_group_hierarchy
   blkcg_activate_policy
    list_for_each_entry_reverse(blkg, &q->blkg_list)
     // blkg is removed from list, hence bfq policy is still NULL

7) throttled io is dispatched to bfq:

 bfq_insert_requests
  bfq_init_rq
   bfq_bic_update_cgroup
    bfq_bio_bfqg
     bfqg = blkg_to_bfqg(blkg)
     // bfqg is NULL because bfq policy is NULL

The problem is only possible in bfq because only bfq can be deactivated and
activated while queue is online, while others can only be deactivated while
the device is removed.

Fix the problem in bfq by checking if blkg is online before calling
blkg_to_bfqg().

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20221108103434.2853269-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-08 07:13:25 -07:00
Yang Li
5b2560c4c2 block: Fix some kernel-doc comments
Remove the description of @required_features in elevator_match()
to clear the below warning:

block/elevator.c:103: warning: Excess function parameter 'required_features' description in 'elevator_match'

Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=2734
Fixes: ffb86425ee ("block: don't check for required features in elevator_match")
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Link: https://lore.kernel.org/r/20221107062255.2685-1-yang.lee@linux.alibaba.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-07 07:21:45 -07:00
Linus Torvalds
4869f5750a block-6.1-2022-11-05
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Merge tag 'block-6.1-2022-11-05' of git://git.kernel.dk/linux

Pull block fixes from Jens Axboe:

 - Fixes for the ublk driver (Ming)

 - Fixes for error handling memory leaks (Chen Jun, Chen Zhongjin)

 - Explicitly clear the last request in a chain when the plug is
   flushed, as it may have already been issued (Al)

* tag 'block-6.1-2022-11-05' of git://git.kernel.dk/linux:
  block: blk_add_rq_to_plug(): clear stale 'last' after flush
  blk-mq: Fix kmemleak in blk_mq_init_allocated_queue
  block: Fix possible memory leak for rq_wb on add_disk failure
  ublk_drv: add ublk_queue_cmd() for cleanup
  ublk_drv: avoid to touch io_uring cmd in blk_mq io path
  ublk_drv: comment on ublk_driver entry of Kconfig
  ublk_drv: return flag of UBLK_F_URING_CMD_COMP_IN_TASK in case of module
2022-11-05 09:02:28 -07:00
Jinlong Chen
4046728253 blk-mq: use if-else instead of goto in blk_mq_alloc_cached_request()
if-else is more readable than goto here.

Signed-off-by: Jinlong Chen <nickyc975@zju.edu.cn>
Link: https://lore.kernel.org/r/d3306fa4e92dc9cc614edc8f1802686096bafef2.1667356813.git.nickyc975@zju.edu.cn
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-02 08:36:50 -06:00
Jinlong Chen
7edfd68165 blk-mq: improve error handling in blk_mq_alloc_rq_map()
Use goto-style error handling like we do elsewhere in the kernel.

Signed-off-by: Jinlong Chen <nickyc975@zju.edu.cn>
Link: https://lore.kernel.org/r/bbbc2d9b17b137798c7fb92042141ca4cbbc58cc.1667356813.git.nickyc975@zju.edu.cn
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-02 08:36:50 -06:00
Chao Leng
414dd48e88 blk-mq: add tagset quiesce interface
Drivers that have shared tagsets may need to quiesce potentially a lot
of request queues that all share a single tagset (e.g. nvme). Add an
interface to quiesce all the queues on a given tagset. This interface is
useful because it can speedup the quiesce by doing it in parallel.

Because some queues should not need to be quiesced (e.g. the nvme
connect_q) when quiescing the tagset, introduce a
QUEUE_FLAG_SKIP_TAGSET_QUIESCE flag to allow this new interface to
ski quiescing a particular queue.

Signed-off-by: Chao Leng <lengchao@huawei.com>
[hch: simplify for the per-tag_set srcu_struct]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Chao Leng <lengchao@huawei.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20221101150050.3510-14-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-02 08:35:34 -06:00
Christoph Hellwig
483239c75b blk-mq: pass a tagset to blk_mq_wait_quiesce_done
Nothing in blk_mq_wait_quiesce_done needs the request_queue now, so just
pass the tagset, and move the non-mq check into the only caller that
needs it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chao Leng <lengchao@huawei.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20221101150050.3510-13-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-02 08:35:34 -06:00
Christoph Hellwig
80bd4a7aab blk-mq: move the srcu_struct used for quiescing to the tagset
All I/O submissions have fairly similar latencies, and a tagset-wide
quiesce is a fairly common operation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Chao Leng <lengchao@huawei.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20221101150050.3510-12-hch@lst.de
[axboe: fix whitespace]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-02 08:35:34 -06:00
Christoph Hellwig
8537380bb9 blk-mq: skip non-mq queues in blk_mq_quiesce_queue
For submit_bio based queues there is no (S)RCU critical section during
I/O submission and thus nothing to wait for in blk_mq_wait_quiesce_done,
so skip doing any synchronization.  No non-mq driver should be calling
this, but for now we have core callers that unconditionally call into it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20221101150050.3510-11-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-02 08:35:34 -06:00
Christoph Hellwig
71b26083d5 block: set the disk capacity to 0 in blk_mark_disk_dead
nvme and xen-blkfront are already doing this to stop buffered writes from
creating dirty pages that can't be written out later.  Move it to the
common code.

This also removes the comment about the ordering from nvme, as bd_mutex
not only is gone entirely, but also hasn't been used for locking updates
to the disk size long before that, and thus the ordering requirement
documented there doesn't apply any more.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Chao Leng <lengchao@huawei.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20221101150050.3510-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-02 08:32:31 -06:00
Yu Kuai
aa625117d6 block, bfq: don't declare 'bfqd' as type 'void *' in bfq_group
Prevent unnecessary format conversion for bfqg->bfqd in multiple
places.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Paolo Valente <paolo.valente@unimore.it>
Link: https://lore.kernel.org/r/20221102022542.3621219-6-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-01 20:10:55 -06:00
Yu Kuai
918fdea388 block, bfq: remove dead code for updating 'rq_in_driver'
Such code are not even compiled since they are inside marco "#if 0".

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Paolo Valente <paolo.valente@unimore.it>
Link: https://lore.kernel.org/r/20221102022542.3621219-5-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-01 20:10:55 -06:00
Yu Kuai
f6fd119b1a block, bfq: cleanup bfq_activate_requeue_entity()
Just make the code a litter cleaner by removing the unnecessary
variable 'sd'.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Paolo Valente <paolo.valente@unimore.it>
Link: https://lore.kernel.org/r/20221102022542.3621219-4-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-01 20:10:54 -06:00
Yu Kuai
e5c63eb4b5 block, bfq: factor out code to update 'active_entities'
Current code is a bit ugly and hard to read.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Paolo Valente <paolo.valente@unimore.it>
Link: https://lore.kernel.org/r/20221102022542.3621219-3-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-01 20:10:54 -06:00
Yu Kuai
060d9217d3 block, bfq: remove set but not used variable in __bfq_entity_update_weight_prio
After the patch "block, bfq: cleanup bfq_weights_tree add/remove apis"),
the local variable 'bfqd' is not used anymore, thus remove it.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20221102022542.3621219-2-yukuai1@huaweicloud.com
Fixes: afdba14612 ("block, bfq: cleanup bfq_weights_tree add/remove apis")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-01 20:10:48 -06:00
Kemeng Shi
dc572f418a block: Replace struct rq_depth with unsigned int in struct iolatency_grp
We only need a max queue depth for every iolatency to limit the inflight io
number. Replace struct rq_depth with unsigned int to simplfy "struct
iolatency_grp" and save memory.

Signed-off-by: Kemeng Shi <shikemeng@huawei.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20221018111240.22612-4-shikemeng@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-01 09:12:24 -06:00
Kemeng Shi
6891f96898 block: Correct comment for scale_cookie_change
Default queue depth of iolatency_grp is unlimited, so we scale down
quickly(once by half) in scale_cookie_change. Remove the "subtract
1/16th" part which is not the truth and add the actual way we
scale down.

Signed-off-by: Kemeng Shi <shikemeng@huawei.com>
Link: https://lore.kernel.org/r/20221018111240.22612-3-shikemeng@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-01 09:12:24 -06:00
Kemeng Shi
db5896e9cf block: Remove redundant parent blkcg_gp check in check_scale_change
Function blkcg_iolatency_throttle will make sure blkg->parent is not
NULL before calls check_scale_change. And function check_scale_change
is only called in blkcg_iolatency_throttle.

Signed-off-by: Kemeng Shi <shikemeng@huawei.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20221018111240.22612-2-shikemeng@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-01 09:12:24 -06:00
Christoph Hellwig
64b36075eb block: split elevator_switch
Split an elevator_disable helper from elevator_switch for the case where
we want to switch to no scheduler at all.  This includes removing the
pointless elevator_switch_mq helper and removing the switch to no
schedule logic from blk_mq_init_sched.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221030100714.876891-8-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-01 09:12:24 -06:00
Christoph Hellwig
ffb86425ee block: don't check for required features in elevator_match
Checking for the required features in the callers simplifies the code
quite a bit, so do that.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221030100714.876891-7-hch@lst.de
[axboe: adjust for dropping patch 1, use __elevator_find()]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-01 09:12:05 -06:00
Christoph Hellwig
2eef17a209 block: simplify the check for the current elevator in elv_iosched_show
Just compare the pointers instead of using the string based
elevator_match.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221030100714.876891-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-01 08:02:47 -06:00
Christoph Hellwig
16095af2fa block: cleanup the variable naming in elv_iosched_store
Use eq for the elevator_queue as done elsewhere.  This frees e to be used
for the loop iterator instead of the odd __ prefix.  In addition rename
elv to cur to make it more clear it is the currently selected elevator.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221030100714.876891-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-01 08:02:47 -06:00
Christoph Hellwig
aae2a643f5 block: exit elv_iosched_show early when I/O schedulers are not supported
If the tag_set has BLK_MQ_F_NO_SCHED flag set we will never show any
scheduler, so exit early.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221030100714.876891-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-01 08:02:47 -06:00
Christoph Hellwig
81eaca442e block: cleanup elevator_get
Do the request_module and repeated lookup in the only caller that cares,
pick a saner name that explains where are actually doing a lookup and
use a sane calling conventions that passes the queue first.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221030100714.876891-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-01 08:02:47 -06:00
Yu Kuai
eb5bca7365 block, bfq: cleanup __bfq_weights_tree_remove()
It's the same with bfq_weights_tree_remove() now.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Paolo Valente <paolo.valente@linaro.org>
Link: https://lore.kernel.org/r/20220916071942.214222-7-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-01 07:09:44 -06:00
Yu Kuai
afdba14612 block, bfq: cleanup bfq_weights_tree add/remove apis
The 'bfq_data' and 'rb_root_cached' can both be accessed through
'bfq_queue', thus only pass 'bfq_queue' as parameter.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Paolo Valente <paolo.valente@linaro.org>
Link: https://lore.kernel.org/r/20220916071942.214222-6-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-01 07:09:44 -06:00
Yu Kuai
eed3ecc991 block, bfq: do not idle if only one group is activated
Now that root group is counted into 'num_groups_with_pending_reqs',
'num_groups_with_pending_reqs > 0' is always true in
bfq_asymmetric_scenario(). Thus change the condition to '> 1'.

On the other hand, this change can enable concurrent sync io if only
one group is activated.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Paolo Valente <paolo.valente@linaro.org>
Link: https://lore.kernel.org/r/20220916071942.214222-5-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-01 07:09:44 -06:00
Yu Kuai
71f8ca77cb block, bfq: refactor the counting of 'num_groups_with_pending_reqs'
Currently, bfq can't handle sync io concurrently as long as they
are not issued from root group. This is because
'bfqd->num_groups_with_pending_reqs > 0' is always true in
bfq_asymmetric_scenario().

The way that bfqg is counted into 'num_groups_with_pending_reqs':

Before this patch:
 1) root group will never be counted.
 2) Count if bfqg or it's child bfqgs have pending requests.
 3) Don't count if bfqg and it's child bfqgs complete all the requests.

After this patch:
 1) root group is counted.
 2) Count if bfqg have pending requests.
 3) Don't count if bfqg complete all the requests.

With this change, the occasion that only one group is activated can be
detected, and next patch will support concurrent sync io in the
occasion.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Paolo Valente <paolo.valente@linaro.org>
Link: https://lore.kernel.org/r/20220916071942.214222-4-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-01 07:09:44 -06:00
Yu Kuai
60a6e10c53 block, bfq: record how many queues have pending requests
Prepare to refactor the counting of 'num_groups_with_pending_reqs'.

Add a counter in bfq_group, update it while tracking if bfqq have pending
requests and when bfq_bfqq_move() is called.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Paolo Valente <paolo.valente@linaro.org>
Link: https://lore.kernel.org/r/20220916071942.214222-3-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-01 07:09:44 -06:00
Yu Kuai
3d89bd12d3 block, bfq: support to track if bfqq has pending requests
If entity belongs to bfqq, then entity->in_groups_with_pending_reqs
is not used currently. This patch use it to track if bfqq has pending
requests through callers of weights_tree insertion and removal.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Paolo Valente <paolo.valente@linaro.org>
Link: https://lore.kernel.org/r/20220916071942.214222-2-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-01 07:09:44 -06:00
Al Viro
878eb6e48f block: blk_add_rq_to_plug(): clear stale 'last' after flush
blk_mq_flush_plug_list() empties ->mq_list and request we'd peeked there
before that call is gone; in any case, we are not dealing with a mix
of requests for different queues now - there's no requests left in the
plug.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-31 20:21:38 -06:00
Chen Jun
943f45b939 blk-mq: Fix kmemleak in blk_mq_init_allocated_queue
There is a kmemleak caused by modprobe null_blk.ko

unreferenced object 0xffff8881acb1f000 (size 1024):
  comm "modprobe", pid 836, jiffies 4294971190 (age 27.068s)
  hex dump (first 32 bytes):
    00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00  .....N..........
    ff ff ff ff ff ff ff ff 00 53 99 9e ff ff ff ff  .........S......
  backtrace:
    [<000000004a10c249>] kmalloc_node_trace+0x22/0x60
    [<00000000648f7950>] blk_mq_alloc_and_init_hctx+0x289/0x350
    [<00000000af06de0e>] blk_mq_realloc_hw_ctxs+0x2fe/0x3d0
    [<00000000e00c1872>] blk_mq_init_allocated_queue+0x48c/0x1440
    [<00000000d16b4e68>] __blk_mq_alloc_disk+0xc8/0x1c0
    [<00000000d10c98c3>] 0xffffffffc450d69d
    [<00000000b9299f48>] 0xffffffffc4538392
    [<0000000061c39ed6>] do_one_initcall+0xd0/0x4f0
    [<00000000b389383b>] do_init_module+0x1a4/0x680
    [<0000000087cf3542>] load_module+0x6249/0x7110
    [<00000000beba61b8>] __do_sys_finit_module+0x140/0x200
    [<00000000fdcfff51>] do_syscall_64+0x35/0x80
    [<000000003c0f1f71>] entry_SYSCALL_64_after_hwframe+0x46/0xb0

That is because q->ma_ops is set to NULL before blk_release_queue is
called.

blk_mq_init_queue_data
  blk_mq_init_allocated_queue
    blk_mq_realloc_hw_ctxs
      for (i = 0; i < set->nr_hw_queues; i++) {
        old_hctx = xa_load(&q->hctx_table, i);
        if (!blk_mq_alloc_and_init_hctx(.., i, ..))		[1]
          if (!old_hctx)
	    break;

      xa_for_each_start(&q->hctx_table, j, hctx, j)
        blk_mq_exit_hctx(q, set, hctx, j); 			[2]

    if (!q->nr_hw_queues)					[3]
      goto err_hctxs;

  err_exit:
      q->mq_ops = NULL;			  			[4]

  blk_put_queue
    blk_release_queue
      if (queue_is_mq(q))					[5]
        blk_mq_release(q);

[1]: blk_mq_alloc_and_init_hctx failed at i != 0.
[2]: The hctxs allocated by [1] are moved to q->unused_hctx_list and
will be cleaned up in blk_mq_release.
[3]: q->nr_hw_queues is 0.
[4]: Set q->mq_ops to NULL.
[5]: queue_is_mq returns false due to [4]. And blk_mq_release
will not be called. The hctxs in q->unused_hctx_list are leaked.

To fix it, call blk_release_queue in exception path.

Fixes: 2f8f1336a4 ("blk-mq: always free hctx after request queue is freed")
Signed-off-by: Yuan Can <yuancan@huawei.com>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20221031031242.94107-1-chenjun102@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-31 08:30:47 -06:00
Jinlong Chen
56c1ee9224 blk-mq: remove redundant call to blk_freeze_queue_start in blk_mq_destroy_queue
The calling relationship in blk_mq_destroy_queue() is as follows:

blk_mq_destroy_queue()
    ...
    -> blk_queue_start_drain()
        -> blk_freeze_queue_start()  <- called
        ...
    -> blk_freeze_queue()
        -> blk_freeze_queue_start()  <- called again
        -> blk_mq_freeze_queue_wait()
    ...

So there is a redundant call to blk_freeze_queue_start().

Replace blk_freeze_queue() with blk_mq_freeze_queue_wait() to avoid the
redundant call.

Signed-off-by: Jinlong Chen <nickyc975@zju.edu.cn>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221030083212.1251255-1-nickyc975@zju.edu.cn
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-31 07:30:42 -06:00
Chen Zhongjin
fa81cbafbf block: Fix possible memory leak for rq_wb on add_disk failure
kmemleak reported memory leaks in device_add_disk():

kmemleak: 3 new suspected memory leaks

unreferenced object 0xffff88800f420800 (size 512):
  comm "modprobe", pid 4275, jiffies 4295639067 (age 223.512s)
  hex dump (first 32 bytes):
    04 00 00 00 08 00 00 00 01 00 00 00 00 00 00 00  ................
    00 e1 f5 05 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<00000000d3662699>] kmalloc_trace+0x26/0x60
    [<00000000edc7aadc>] wbt_init+0x50/0x6f0
    [<0000000069601d16>] wbt_enable_default+0x157/0x1c0
    [<0000000028fc393f>] blk_register_queue+0x2a4/0x420
    [<000000007345a042>] device_add_disk+0x6fd/0xe40
    [<0000000060e6aab0>] nbd_dev_add+0x828/0xbf0 [nbd]
    ...

It is because the memory allocated in wbt_enable_default() is not
released in device_add_disk() error path.
Normally, these memory are freed in:

del_gendisk()
  rq_qos_exit()
    rqos->ops->exit(rqos);
      wbt_exit()

So rq_qos_exit() is called to free the rq_wb memory for wbt_init().
However in the error path of device_add_disk(), only
blk_unregister_queue() is called and make rq_wb memory leaked.

Add rq_qos_exit() to the error path to fix it.

Fixes: 83cbce9574 ("block: add error handling for device_add_disk / add_disk")
Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221029071355.35462-1-chenzhongjin@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-31 07:29:53 -06:00
Jinlong Chen
219cf43c55 blk-mq: move queue_is_mq out of blk_mq_cancel_work_sync
The only caller that needs queue_is_mq check is del_gendisk, so move the
check into it.

Signed-off-by: Jinlong Chen <nickyc975@zju.edu.cn>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221030094730.1275463-1-nickyc975@zju.edu.cn
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-31 07:27:54 -06:00
David Jeffery
82c229476b blk-mq: avoid double ->queue_rq() because of early timeout
David Jeffery found one double ->queue_rq() issue, so far it can
be triggered in VM use case because of long vmexit latency or preempt
latency of vCPU pthread or long page fault in vCPU pthread, then block
IO req could be timed out before queuing the request to hardware but after
calling blk_mq_start_request() during ->queue_rq(), then timeout handler
may handle it by requeue, then double ->queue_rq() is caused, and kernel
panic.

So far, it is driver's responsibility to cover the race between timeout
and completion, so it seems supposed to be solved in driver in theory,
given driver has enough knowledge.

But it is really one common problem, lots of driver could have similar
issue, and could be hard to fix all affected drivers, even it isn't easy
for driver to handle the race. So David suggests this patch by draining
in-progress ->queue_rq() for solving this issue.

Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Keith Busch <kbusch@kernel.org>
Cc: virtualization@lists.linux-foundation.org
Cc: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: David Jeffery <djeffery@redhat.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20221026051957.358818-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-31 07:24:22 -06:00
Linus Torvalds
c6e0e874a8 block-6.1-2022-10-28
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Merge tag 'block-6.1-2022-10-28' of git://git.kernel.dk/linux

Pull block fixes from Jens Axboe:

 - NVMe pull request via Christoph:
      - make the multipath dma alignment match the non-multipath one
        (Keith Busch)
      - fix a bogus use of sg_init_marker() (Nam Cao)
      - fix circulr locking in nvme-tcp (Sagi Grimberg)

 - Initialization fix for requests allocated via the special hw queue
   allocator (John)

 - Fix for a regression added in this release with the batched
   completions of end_io backed requests (Ming)

 - Error handling leak fix for rbd (Yang)

 - Error handling leak fix for add_disk() failure (Yu)

* tag 'block-6.1-2022-10-28' of git://git.kernel.dk/linux:
  blk-mq: Properly init requests from blk_mq_alloc_request_hctx()
  blk-mq: don't add non-pt request with ->end_io to batch
  rbd: fix possible memory leak in rbd_sysfs_init()
  nvme-multipath: set queue dma alignment to 3
  nvme-tcp: fix possible circular locking when deleting a controller under memory pressure
  nvme-tcp: replace sg_init_marker() with sg_init_table()
  block: fix memory leak for elevator on add_disk failure
2022-10-29 18:06:52 -07:00
John Garry
e3c5a78cdb blk-mq: Properly init requests from blk_mq_alloc_request_hctx()
Function blk_mq_alloc_request_hctx() is missing zeroing/init of rq->bio,
biotail, __sector, and __data_len members, which blk_mq_alloc_request()
has, so duplicate what we do in blk_mq_alloc_request().

Fixes: 1f5bd336b9 ("blk-mq: add blk_mq_alloc_request_hctx")
Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/1666780513-121650-1-git-send-email-john.garry@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-28 07:54:47 -06:00
Bart Van Assche
9546531884 block: Micro-optimize get_max_segment_size()
This patch removes a conditional jump from get_max_segment_size(). The
x86-64 assembler code for this function without this patch is as follows:

206             return min_not_zero(mask - offset + 1,
   0x0000000000000118 <+72>:    not    %rax
   0x000000000000011b <+75>:    and    0x8(%r10),%rax
   0x000000000000011f <+79>:    add    $0x1,%rax
   0x0000000000000123 <+83>:    je     0x138 <bvec_split_segs+104>
   0x0000000000000125 <+85>:    cmp    %rdx,%rax
   0x0000000000000128 <+88>:    mov    %rdx,%r12
   0x000000000000012b <+91>:    cmovbe %rax,%r12
   0x000000000000012f <+95>:    test   %rdx,%rdx
   0x0000000000000132 <+98>:    mov    %eax,%edx
   0x0000000000000134 <+100>:   cmovne %r12d,%edx

With this patch applied:

206             return min(mask - offset, (unsigned long)lim->max_segment_size - 1) + 1;
   0x000000000000003f <+63>:    mov    0x28(%rdi),%ebp
   0x0000000000000042 <+66>:    not    %rax
   0x0000000000000045 <+69>:    and    0x8(%rdi),%rax
   0x0000000000000049 <+73>:    sub    $0x1,%rbp
   0x000000000000004d <+77>:    cmp    %rbp,%rax
   0x0000000000000050 <+80>:    cmova  %rbp,%rax
   0x0000000000000054 <+84>:    add    $0x1,%eax

Reviewed-by: Ming Lei <ming.lei@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Keith Busch <kbusch@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20221025191755.1711437-4-bvanassche@acm.org
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-25 13:41:20 -06:00
Bart Van Assche
aa261f2058 block: Constify most queue limits pointers
Document which functions do not modify the queue limits.

Reviewed-by: Ming Lei <ming.lei@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Keith Busch <kbusch@kernel.org>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20221025191755.1711437-3-bvanassche@acm.org
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-25 13:41:17 -06:00
Christoph Hellwig
a55b70f127 block: remove bio_start_io_acct_time
bio_start_io_acct_time is not actually used anywhere, so remove it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221025155916.270303-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-25 12:08:31 -06:00
Christoph Hellwig
2b3f056f72 blk-mq: move the call to blk_put_queue out of blk_mq_destroy_queue
The fact that blk_mq_destroy_queue also drops a queue reference leads
to various places having to grab an extra reference.  Move the call to
blk_put_queue into the callers to allow removing the extra references.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Link: https://lore.kernel.org/r/20221018135720.670094-2-hch@lst.de
[axboe: fix fabrics_q vs admin_q conflict in nvme core.c]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-25 08:25:10 -06:00
Jinlong Chen
8ed40ee35d block: fix up elevator_type refcounting
The current reference management logic of io scheduler modules contains
refcnt problems. For example, blk_mq_init_sched may fail before or after
the calling of e->ops.init_sched. If it fails before the calling, it does
nothing to the reference to the io scheduler module. But if it fails after
the calling, it releases the reference by calling kobject_put(&eq->kobj).

As the callers of blk_mq_init_sched can't know exactly where the failure
happens, they can't handle the reference to the io scheduler module
properly: releasing the reference on failure results in double-release if
blk_mq_init_sched has released it, and not releasing the reference results
in ghost reference if blk_mq_init_sched did not release it either.

The same problem also exists in io schedulers' init_sched implementations.

We can address the problem by adding releasing statements to the error
handling procedures of blk_mq_init_sched and init_sched implementations.
But that is counterintuitive and requires modifications to existing io
schedulers.

Instead, We make elevator_alloc get the io scheduler module references
that will be released by elevator_release. And then, we match each
elevator_get with an elevator_put. Therefore, each reference to an io
scheduler module explicitly has its own getter and releaser, and we no
longer need to worry about the refcnt problems.

The bugs and the patch can be validated with tools here:
https://github.com/nickyc975/linux_elv_refcnt_bug.git

[hch: split out a few bits into separate patches, use a non-try
      module_get in elevator_alloc]

Signed-off-by: Jinlong Chen <nickyc975@zju.edu.cn>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221020064819.1469928-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-23 18:59:17 -06:00
Jinlong Chen
b54c2ad9b7 block: check for an unchanged elevator earlier in __elevator_change
No need to find the actual elevator_type struct for this comparism,
the name is all that is needed.

Signed-off-by: Jinlong Chen <nickyc975@zju.edu.cn>
[hch: split from a larger patch]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221020064819.1469928-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-23 18:59:17 -06:00
Christoph Hellwig
58367c8a5f block: sanitize the elevator name before passing it to __elevator_change
The stripped name should also be used for the none check.  To do so
strip it in the caller and pass in the sanitized name.  Drop the pointless
__ prefix in the function name while we're at it.

Based on a patch from Jinlong Chen <nickyc975@zju.edu.cn>.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221020064819.1469928-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-23 18:59:17 -06:00
Christoph Hellwig
dd6f7f17bf block: add proper helpers for elevator_type module refcount management
Make sure we have helpers for all relevant module refcount operations on
the elevator_type in elevator.h, and use them.  Move the call to the get
helper in blk_mq_elv_switch_none a bit so that it is obvious with a less
verbose comment.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221020064819.1469928-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-23 18:59:17 -06:00
Yu Kuai
671fae5e51 blk-wbt: don't enable throttling if default elevator is bfq
Commit b5dc5d4d1f ("block,bfq: Disable writeback throttling") tries to
disable wbt for bfq, it's done by calling wbt_disable_default() in
bfq_init_queue(). However, wbt is still enabled if default elevator is
bfq:

device_add_disk
 elevator_init_mq
  bfq_init_queue
   wbt_disable_default -> done nothing

 blk_register_queue
  wbt_enable_default -> wbt is enabled

Fix the problem by adding a new flag ELEVATOR_FLAG_DISBALE_WBT, bfq
will set the flag in bfq_init_queue, and following wbt_enable_default()
won't enable wbt while the flag is set.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221019121518.3865235-7-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-23 18:59:17 -06:00
Yu Kuai
181d066374 elevator: add new field flags in struct elevator_queue
There are only one flag to indicate that elevator is registered currently,
prepare to add a flag to disable wbt if default elevator is bfq.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221019121518.3865235-6-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-23 18:59:17 -06:00
Yu Kuai
3642ef4d95 blk-wbt: don't show valid wbt_lat_usec in sysfs while wbt is disabled
Currently, if wbt is initialized and then disabled by
wbt_disable_default(), sysfs will still show valid wbt_lat_usec, which
will confuse users that wbt is still enabled.

This patch shows wbt_lat_usec as zero if it's disabled.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reported-and-tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221019121518.3865235-5-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-23 18:59:17 -06:00
Yu Kuai
a9a236d238 blk-wbt: make enable_state more accurate
Currently, if user disable wbt through sysfs, 'enable_state' will be
'WBT_STATE_ON_MANUAL', which will be confusing. Add a new state
'WBT_STATE_OFF_MANUAL' to cover that case.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221019121518.3865235-4-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-23 18:59:17 -06:00
Yu Kuai
b11d31ae01 blk-wbt: remove unnecessary check in wbt_enable_default()
If CONFIG_BLK_WBT_MQ is disabled, wbt_init() won't do anything.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221019121518.3865235-3-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-23 18:59:17 -06:00
Yu Kuai
6d9f4cf125 elevator: remove redundant code in elv_unregister_queue()
"elevator_queue *e" is already declared and initialized in the beginning
of elv_unregister_queue().

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20221019121518.3865235-2-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-23 18:59:17 -06:00
Yu Kuai
074501bce3 blk-iocost: read 'ioc->params' inside 'ioc->lock' in ioc_timer_fn()
'ioc->params' is updated in ioc_refresh_params(), which is proteced by
'ioc->lock', however, ioc_timer_fn() read params outside the lock.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20221012094035.390056-5-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-23 18:59:17 -06:00
Yu Kuai
2b2da2f6dc blk-iocost: prevent configuration update concurrent with io throttling
This won't cause any severe problem currently, however, this doesn't
seems appropriate:

1) 'ioc->params' is read from multiple places without holding
'ioc->lock', unexpected value might be read if writing it concurrently.

2) If configuration is changed while io is throttling, the functionality
might be affected. For example, if module params is updated and cost
becomes smaller, waiting for timer that is caculated under old
configuration is not appropriate.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20221012094035.390056-4-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-23 18:59:16 -06:00
Yu Kuai
2c06479884 blk-iocost: don't release 'ioc->lock' while updating params
ioc_qos_write() and ioc_cost_model_write() are the same:

1) hold lock to read 'ioc->params' to local variable;
2) update params to local variable without lock;
3) hold lock to write local variable to 'ioc->params';

In theroy, if user updates params concurrenty, the params might be lost:

t1: update params a		t2: update params b
spin_lock_irq(&ioc->lock);
memcpy(qos, ioc->params.qos, sizeof(qos))
spin_unlock_irq(&ioc->lock);

qos[a] = xxx;

				spin_lock_irq(&ioc->lock);
				memcpy(qos, ioc->params.qos, sizeof(qos))
				spin_unlock_irq(&ioc->lock);

				qos[b] = xxx;

spin_lock_irq(&ioc->lock);
memcpy(ioc->params.qos, qos, sizeof(qos));
ioc_refresh_params(ioc, true);
spin_unlock_irq(&ioc->lock);

				spin_lock_irq(&ioc->lock);
				// updates of a will be lost
				memcpy(ioc->params.qos, qos, sizeof(qos));
				ioc_refresh_params(ioc, true);
				spin_unlock_irq(&ioc->lock);

Althrough this is not common case, the problem can by fixed easily by
holding the lock through the read, update, write process.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20221012094035.390056-3-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-23 18:59:16 -06:00
Yu Kuai
8796acbc9a blk-iocost: disable writeback throttling
Commit b5dc5d4d1f ("block,bfq: Disable writeback throttling") disable
wbt for bfq, because different write-throttling heuristics should not
work together.

For the same reason, wbt and iocost should not work together as well,
unless admin really want to do that, dispite that performance is
affected.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20221012094035.390056-2-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-23 18:59:16 -06:00
Yu Kuai
02341a08c9 block: fix memory leak for elevator on add_disk failure
The default elevator is allocated in the beginning of device_add_disk(),
however, it's not freed in the following error path.

Fixes: 50e34d7881 ("block: disable the elevator int del_gendisk")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Yan <yanaijie@huawei.com>
Link: https://lore.kernel.org/r/20221022021615.2756171-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-22 15:14:38 -06:00
Linus Torvalds
d4b7332eef block-6.1-2022-10-20
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Merge tag 'block-6.1-2022-10-20' of git://git.kernel.dk/linux

Pull block fixes from Jens Axboe:

 - NVMe pull request via Christoph:
      - fix nvme-hwmon for DMA non-cohehrent architectures (Serge Semin)
      - add a nvme-hwmong maintainer (Christoph Hellwig)
      - fix error pointer dereference in error handling (Dan Carpenter)
      - fix invalid memory reference in nvmet_subsys_attr_qid_max_show
        (Daniel Wagner)
      - don't limit the DMA segment size in nvme-apple (Russell King)
      - fix workqueue MEM_RECLAIM flushing dependency (Sagi Grimberg)
      - disable write zeroes on various Kingston SSDs (Xander Li)

 - fix a memory leak with block device tracing (Ye)

 - flexible-array fix for ublk (Yushan)

 - document the ublk recovery feature from this merge window
   (ZiyangZhang)

 - remove dead bfq variable in struct (Yuwei)

 - error handling rq clearing fix (Yu)

 - add an IRQ safety check for the cached bio freeing (Pavel)

 - drbd bio cloning fix (Christoph)

* tag 'block-6.1-2022-10-20' of git://git.kernel.dk/linux:
  blktrace: remove unnessary stop block trace in 'blk_trace_shutdown'
  blktrace: fix possible memleak in '__blk_trace_remove'
  blktrace: introduce 'blk_trace_{start,stop}' helper
  bio: safeguard REQ_ALLOC_CACHE bio put
  block, bfq: remove unused variable for bfq_queue
  drbd: only clone bio if we have a backing device
  ublk_drv: use flexible-array member instead of zero-length array
  nvmet: fix invalid memory reference in nvmet_subsys_attr_qid_max_show
  nvmet: fix workqueue MEM_RECLAIM flushing dependency
  nvme-hwmon: kmalloc the NVME SMART log buffer
  nvme-hwmon: consistently ignore errors from nvme_hwmon_init
  nvme: add Guenther as nvme-hwmon maintainer
  nvme-apple: don't limit DMA segement size
  nvme-pci: disable write zeroes on various Kingston SSD
  nvme: fix error pointer dereference in error handling
  Documentation: document ublk user recovery feature
  blk-mq: fix null pointer dereference in blk_mq_clear_rq_mapping()
2022-10-21 15:14:14 -07:00
Pavel Begunkov
d4347d5040 bio: safeguard REQ_ALLOC_CACHE bio put
bio_put() with REQ_ALLOC_CACHE assumes that it's executed not from
an irq context. Let's add a warning if the invariant is not respected,
especially since there is a couple of places removing REQ_POLLED by hand
without also clearing REQ_ALLOC_CACHE.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/558d78313476c4e9c233902efa0092644c3d420a.1666122465.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-20 05:50:29 -07:00
Yuwei Guan
33566f92cd block, bfq: remove unused variable for bfq_queue
it defined in d0edc2473b, but there's nowhere to use it,
so remove it.

Signed-off-by: Yuwei Guan <Yuwei.Guan@zeekrlife.com>
Acked-by: Paolo Valente <paolo.valente@linaro.org>
Link: https://lore.kernel.org/r/20221018030139.159-1-Yuwei.Guan@zeekrlife.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-20 05:46:49 -07:00
Yu Kuai
76dd298094 blk-mq: fix null pointer dereference in blk_mq_clear_rq_mapping()
Our syzkaller report a null pointer dereference, root cause is
following:

__blk_mq_alloc_map_and_rqs
 set->tags[hctx_idx] = blk_mq_alloc_map_and_rqs
  blk_mq_alloc_map_and_rqs
   blk_mq_alloc_rqs
    // failed due to oom
    alloc_pages_node
    // set->tags[hctx_idx] is still NULL
    blk_mq_free_rqs
     drv_tags = set->tags[hctx_idx];
     // null pointer dereference is triggered
     blk_mq_clear_rq_mapping(drv_tags, ...)

This is because commit 63064be150 ("blk-mq:
Add blk_mq_alloc_map_and_rqs()") merged the two steps:

1) set->tags[hctx_idx] = blk_mq_alloc_rq_map()
2) blk_mq_alloc_rqs(..., set->tags[hctx_idx])

into one step:

set->tags[hctx_idx] = blk_mq_alloc_map_and_rqs()

Since tags is not initialized yet in this case, fix the problem by
checking if tags is NULL pointer in blk_mq_clear_rq_mapping().

Fixes: 63064be150 ("blk-mq: Add blk_mq_alloc_map_and_rqs()")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: John Garry <john.garry@huawei.com>
Link: https://lore.kernel.org/r/20221011142253.4015966-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-16 17:22:51 -06:00