This reverts commit cb2ac291.

Alex and the kernel test robot report that this causes a significant
performance regression with BFQ. I can reproduce that result, so let's
revert this one as we're close to -rc6 and we there's no point in trying
to rush a fix.

Link: https://lore.kernel.org/linux-block/1639853092.524jxfaem2.none@localhost/
Link: https://lore.kernel.org/lkml/20211219141852.GH14057@xsang-OptiPlex-9020/


Reported-by: Alex Xu (Hello71) <alex_y_xu@yahoo.ca>
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Dexuan reports that he's seeing spikes of very heavy CPU utilization when
running 24 disks and using the 'none' scheduler. This happens off the
sched restart path, because SCSI requires the queue to be restarted async,
and hence we're hammering on mod_delayed_work_on() to ensure that the work
item gets run appropriately.

Avoid hammering on the timer and just use queue_work_on() if no delay
has been specified.

Reported-and-tested-by: Dexuan Cui <decui@microsoft.com>
Link: https://lore.kernel.org/linux-block/BYAPR21MB1270C598ED214C0490F47400BF719@BYAPR21MB1270.namprd21.prod.outlook.com/


Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

The donation calculation logic assumes that the donor has non-zero
after-donation hweight, so the lowest active hweight a donating cgroup can
have is 2 so that it can donate 1 while keeping the other 1 for itself.
Earlier, we only donated from cgroups with sizable surpluses so this
condition was always true. However, with the precise donation algorithm
implemented, f1de2439 ("blk-iocost: revamp donation amount
determination") made the donation amount calculation exact enabling even low
hweight cgroups to donate.

This means that in rare occasions, a cgroup with active hweight of 1 can
enter donation calculation triggering the following warning and then a
divide-by-zero oops.

 WARNING: CPU: 4 PID: 0 at block/blk-iocost.c:1928 transfer_surpluses.cold+0x0/0x53 [884/94867]
 ...
 RIP: 0010:transfer_surpluses.cold+0x0/0x53
 Code: 92 ff 48 c7 c7 28 d1 ab b5 65 48 8b 34 25 00 ae 01 00 48 81 c6 90 06 00 00 e8 8b 3f fe ff 48 c7 c0 ea ff ff ff e9 95 ff 92 ff <0f> 0b 48 c7 c7 30 da ab b5 e8 71 3f fe ff 4c 89 e8 4d 85 ed 74 0
4
 ...
 Call Trace:
  <IRQ>
  ioc_timer_fn+0x1043/0x1390
  call_timer_fn+0xa1/0x2c0
  __run_timers.part.0+0x1ec/0x2e0
  run_timer_softirq+0x35/0x70
 ...
 iocg: invalid donation weights in /a/b: active=1 donating=1 after=0

Fix it by excluding cgroups w/ active hweight < 2 from donating. Excluding
these extreme low hweight donations shouldn't affect work conservation in
any meaningful way.

Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: f1de2439 ("blk-iocost: revamp donation amount determination")
Cc: stable@vger.kernel.org # v5.10+
Link: https://lore.kernel.org/r/Ybfh86iSvpWKxhVM@slm.duckdns.org


Signed-off-by: Jens Axboe <axboe@kernel.dk>

do_each_pid_thread(PIDTYPE_PGID) can race with a concurrent
change_pid(PIDTYPE_PGID) that can move the task from one hlist
to another while iterating. Serialize ioprio_get to take
the tasklist_lock in this case, just like it's set counterpart.

Fixes: d69b78ba (ioprio: grab rcu_read_lock in sys_ioprio_{set,get}())
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Link: https://lore.kernel.org/r/20211210182058.43417-1-dave@stgolabs.net


Signed-off-by: Jens Axboe <axboe@kernel.dk>

BUG: KASAN: use-after-free in io_submit_one+0x496/0x2fe0 fs/aio.c:1882
CPU: 2 PID: 15100 Comm: syz-executor873 Not tainted 5.16.0-rc1-syzk #1
Hardware name: Red Hat KVM, BIOS 1.13.0-2.module+el8.3.0+7860+a7792d29
04/01/2014
Call Trace:
  [...]
  refcount_dec_and_test include/linux/refcount.h:333 [inline]
  iocb_put fs/aio.c:1161 [inline]
  io_submit_one+0x496/0x2fe0 fs/aio.c:1882
  __do_sys_io_submit fs/aio.c:1938 [inline]
  __se_sys_io_submit fs/aio.c:1908 [inline]
  __x64_sys_io_submit+0x1c7/0x4a0 fs/aio.c:1908
  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
  do_syscall_64+0x3a/0x80 arch/x86/entry/common.c:80
  entry_SYSCALL_64_after_hwframe+0x44/0xae

__blkdev_direct_IO_async() returns errors from bio_iov_iter_get_pages()
directly, in which case upper layers won't be expecting ->ki_complete
to be called by the block layer and will terminate the request. However,
there is also bio_endio() leading to a second ->ki_complete and a double
free.

Fixes: 54a88eb8 ("block: add single bio async direct IO helper")
Reported-by: George Kennedy <george.kennedy@oracle.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/c9eb786f6cef041e159e6287de131bec0719ad5c.1638907997.git.asml.silence@gmail.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

cgroup.h (therefore swap.h, therefore half of the universe)
includes bpf.h which in turn includes module.h and slab.h.
Since we're about to get rid of that dependency we need
to clean things up.

v2: drop the cpu.h include from cacheinfo.h, it's not necessary
and it makes riscv sensitive to ordering of include files.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Krzysztof Wilczyński <kw@linux.com>
Acked-by: Peter Chen <peter.chen@kernel.org>
Acked-by: SeongJae Park <sj@kernel.org>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/all/20211120035253.72074-1-kuba@kernel.org/  # v1
Link: https://lore.kernel.org/all/20211120165528.197359-1-kuba@kernel.org/ # cacheinfo discussion
Link: https://lore.kernel.org/bpf/20211202203400.1208663-1-kuba@kernel.org

We need to call rq_qos_done() regardless of whether or not we're freeing
the request or not, as the reference count doesn't cover the IO completion
tracking.

Fixes: f794f335 ("block: add support for blk_mq_end_request_batch()")
Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Reported-by: Kenneth R. Crudup <kenny@panix.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

The build warning:
block/blk-core.c:968: warning: Function parameter or member 'iob'
not described in 'bio_poll'.

Fixes: 5a72e899 ("block: add a struct io_comp_batch argument to fops->iopoll()")
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Yang Guang <yang.guang5@zte.com.cn>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

disk->fops->owner is grabbed in blkdev_get_no_open() after the disk
kobject refcount is increased. This way can't make sure that
disk->fops->owner is still alive since del_gendisk() still can move
on if the kobject refcount of disk is grabbed by open() and
disk->fops->open() isn't called yet.

Fixes the issue by moving try_module_get() into blkdev_get_by_dev()
with ->open_mutex() held, then we can drain the in-progress open()
in del_gendisk(). Meantime new open() won't succeed because disk
becomes not alive.

This way is reasonable because blkdev_get_no_open() needn't to touch
disk->fops or defined callbacks.

Cc: Christoph Hellwig <hch@lst.de>
Cc: czhong@redhat.com
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211111020343.316126-1-ming.lei@redhat.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

We never insert flush request into scheduler queue before.

Recently commit d92ca9d8 ("blk-mq: don't handle non-flush requests in
blk_insert_flush") tries to handle FUA data request as normal request.
This way has caused warning[1] in mq-deadline dd_exit_sched() or io hang in
case of kyber since RQF_ELVPRIV isn't set for flush request, then
->finish_request won't be called.

Fix the issue by inserting FUA data request with blk_mq_request_bypass_insert()
when the device supports FUA, just like what we did before.

[1] https://lore.kernel.org/linux-block/CAHj4cs-_vkTW=dAzbZYGxpEWSpzpcmaNeY1R=vH311+9vMUSdg@mail.gmail.com/



Reported-by: Yi Zhang <yi.zhang@redhat.com>
Fixes: d92ca9d8 ("blk-mq: don't handle non-flush requests in blk_insert_flush")
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20211118153041.2163228-1-ming.lei@redhat.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

If blk_queue_enter() failed due to queue is dying, the
blkdev_put_no_open() is needed because blkcg_conf_open_bdev() succeeded.

Fixes: 0c9d338c ("blk-cgroup: synchronize blkg creation against policy deactivation")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20211102020705.2321858-1-yukuai3@huawei.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

elevator_init_mq() is only called before adding disk, when there isn't
any FS I/O, only passthrough requests can be queued, so freezing queue
plus canceling dispatch work is enough to drain any dispatch activities,
then we can avoid synchronize_srcu() in blk_mq_quiesce_queue().

Long boot latency issue can be fixed in case of lots of disks added
during booting.

Fixes: 737eb78e ("block: Delay default elevator initialization")
Reported-by: yangerkun <yangerkun@huawei.com>
Cc: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211117115502.1600950-1-ming.lei@redhat.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

For avoiding to slow down queue destroy, we don't call
blk_mq_quiesce_queue() in blk_cleanup_queue(), instead of delaying to
cancel dispatch work in blk_release_queue().

However, this way has caused kernel oops[1], reported by Changhui. The log
shows that scsi_device can be freed before running blk_release_queue(),
which is expected too since scsi_device is released after the scsi disk
is closed and the scsi_device is removed.

Fixes the issue by canceling blk-mq dispatch work in both blk_cleanup_queue()
and disk_release():

1) when disk_release() is run, the disk has been closed, and any sync
dispatch activities have been done, so canceling dispatch work is enough to
quiesce filesystem I/O dispatch activity.

2) in blk_cleanup_queue(), we only focus on passthrough request, and
passthrough request is always explicitly allocated & freed by
its caller, so once queue is frozen, all sync dispatch activity
for passthrough request has been done, then it is enough to just cancel
dispatch work for avoiding any dispatch activity.

[1] kernel panic log
[12622.769416] BUG: kernel NULL pointer dereference, address: 0000000000000300
[12622.777186] #PF: supervisor read access in kernel mode
[12622.782918] #PF: error_code(0x0000) - not-present page
[12622.788649] PGD 0 P4D 0
[12622.791474] Oops: 0000 [#1] PREEMPT SMP PTI
[12622.796138] CPU: 10 PID: 744 Comm: kworker/10:1H Kdump: loaded Not tainted 5.15.0+ #1
[12622.804877] Hardware name: Dell Inc. PowerEdge R730/0H21J3, BIOS 1.5.4 10/002/2015
[12622.813321] Workqueue: kblockd blk_mq_run_work_fn
[12622.818572] RIP: 0010:sbitmap_get+0x75/0x190
[12622.823336] Code: 85 80 00 00 00 41 8b 57 08 85 d2 0f 84 b1 00 00 00 45 31 e4 48 63 cd 48 8d 1c 49 48 c1 e3 06 49 03 5f 10 4c 8d 6b 40 83 f0 01 <48> 8b 33 44 89 f2 4c 89 ef 0f b6 c8 e8 fa f3 ff ff 83 f8 ff 75 58
[12622.844290] RSP: 0018:ffffb00a446dbd40 EFLAGS: 00010202
[12622.850120] RAX: 0000000000000001 RBX: 0000000000000300 RCX: 0000000000000004
[12622.858082] RDX: 0000000000000006 RSI: 0000000000000082 RDI: ffffa0b7a2dfe030
[12622.866042] RBP: 0000000000000004 R08: 0000000000000001 R09: ffffa0b742721334
[12622.874003] R10: 0000000000000008 R11: 0000000000000008 R12: 0000000000000000
[12622.881964] R13: 0000000000000340 R14: 0000000000000000 R15: ffffa0b7a2dfe030
[12622.889926] FS:  0000000000000000(0000) GS:ffffa0baafb40000(0000) knlGS:0000000000000000
[12622.898956] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[12622.905367] CR2: 0000000000000300 CR3: 0000000641210001 CR4: 00000000001706e0
[12622.913328] Call Trace:
[12622.916055]  <TASK>
[12622.918394]  scsi_mq_get_budget+0x1a/0x110
[12622.922969]  __blk_mq_do_dispatch_sched+0x1d4/0x320
[12622.928404]  ? pick_next_task_fair+0x39/0x390
[12622.933268]  __blk_mq_sched_dispatch_requests+0xf4/0x140
[12622.939194]  blk_mq_sched_dispatch_requests+0x30/0x60
[12622.944829]  __blk_mq_run_hw_queue+0x30/0xa0
[12622.949593]  process_one_work+0x1e8/0x3c0
[12622.954059]  worker_thread+0x50/0x3b0
[12622.958144]  ? rescuer_thread+0x370/0x370
[12622.962616]  kthread+0x158/0x180
[12622.966218]  ? set_kthread_struct+0x40/0x40
[12622.970884]  ret_from_fork+0x22/0x30
[12622.974875]  </TASK>
[12622.977309] Modules linked in: scsi_debug rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace fscache netfs sunrpc dm_multipath intel_rapl_msr intel_rapl_common dell_wmi_descriptor sb_edac rfkill video x86_pkg_temp_thermal intel_powerclamp dcdbas coretemp kvm_intel kvm mgag200 irqbypass i2c_algo_bit rapl drm_kms_helper ipmi_ssif intel_cstate intel_uncore syscopyarea sysfillrect sysimgblt fb_sys_fops pcspkr cec mei_me lpc_ich mei ipmi_si ipmi_devintf ipmi_msghandler acpi_power_meter drm fuse xfs libcrc32c sr_mod cdrom sd_mod t10_pi sg ixgbe ahci libahci crct10dif_pclmul crc32_pclmul crc32c_intel libata megaraid_sas ghash_clmulni_intel tg3 wdat_wdt mdio dca wmi dm_mirror dm_region_hash dm_log dm_mod [last unloaded: scsi_debug]

Reported-by: ChanghuiZhong <czhong@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: linux-scsi@vger.kernel.org
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211116014343.610501-1-ming.lei@redhat.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

If we fail the submission queue checks, we don't put the queue afterwards.
This can cause various issues like stalls on scheduler switch or failure
to remove the device, or like in the original bug report, timeout waiting
for the device on reboot/restart.

While in there, fix a few whitespace discrepancies in the surrounding
code.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=215039


Fixes: b637108a ("blk-mq: fix filesystem I/O request allocation")
Reported-and-tested-by: Stephen Smith <stephenmsmith@blueyonder.co.uk>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Booting to Android userspace on 5.14 or newer triggers the following
SELinux denial:

avc: denied { sys_nice } for comm="init" capability=23
     scontext=u:r:init:s0 tcontext=u:r:init:s0 tclass=capability
     permissive=0

Init is PID 0 running as root, so it already has CAP_SYS_ADMIN. For
better compatibility with older SEPolicy, check ADMIN before NICE.

Fixes: 9d3a39a5 ("block: grant IOPRIO_CLASS_RT to CAP_SYS_NICE")
Signed-off-by: Alistair Delva <adelva@google.com>
Cc: Khazhismel Kumykov <khazhy@google.com>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Serge Hallyn <serge@hallyn.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Paul Moore <paul@paul-moore.com>
Cc: selinux@vger.kernel.org
Cc: linux-security-module@vger.kernel.org
Cc: kernel-team@android.com
Cc: stable@vger.kernel.org # v5.14+
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: Serge Hallyn <serge@hallyn.com>
Link: https://lore.kernel.org/r/20211115181655.3608659-1-adelva@google.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

submit_bio_checks() may update bio->bi_opf, so we have to initialize
blk_mq_alloc_data.cmd_flags with bio->bi_opf after submit_bio_checks()
returns when allocating new request.

In case of using cached request, fallback to allocate new request if
cached rq isn't compatible with the incoming bio, otherwise change
rq->cmd_flags with incoming bio->bi_opf.

Fixes: 900e0807 ("block: move queue enter logic into blk_mq_submit_bio()")
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

KASAN reports a use-after-free report when doing block test:

==================================================================
[10050.967049] BUG: KASAN: use-after-free in
submit_bio_checks+0x1539/0x1550

[10050.977638] Call Trace:
[10050.978190]  dump_stack+0x9b/0xce
[10050.979674]  print_address_description.constprop.6+0x3e/0x60
[10050.983510]  kasan_report.cold.9+0x22/0x3a
[10050.986089]  submit_bio_checks+0x1539/0x1550
[10050.989576]  submit_bio_noacct+0x83/0xc80
[10050.993714]  submit_bio+0xa7/0x330
[10050.994435]  mpage_readahead+0x380/0x500
[10050.998009]  read_pages+0x1c1/0xbf0
[10051.002057]  page_cache_ra_unbounded+0x4c2/0x6f0
[10051.007413]  do_page_cache_ra+0xda/0x110
[10051.008207]  force_page_cache_ra+0x23d/0x3d0
[10051.009087]  page_cache_sync_ra+0xca/0x300
[10051.009970]  generic_file_buffered_read+0xbea/0x2130
[10051.012685]  generic_file_read_iter+0x315/0x490
[10051.014472]  blkdev_read_iter+0x113/0x1b0
[10051.015300]  aio_read+0x2ad/0x450
[10051.023786]  io_submit_one+0xc8e/0x1d60
[10051.029855]  __se_sys_io_submit+0x125/0x350
[10051.033442]  do_syscall_64+0x2d/0x40
[10051.034156]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

[10051.048733] Allocated by task 18598:
[10051.049482]  kasan_save_stack+0x19/0x40
[10051.050263]  __kasan_kmalloc.constprop.1+0xc1/0xd0
[10051.051230]  kmem_cache_alloc+0x146/0x440
[10051.052060]  mempool_alloc+0x125/0x2f0
[10051.052818]  bio_alloc_bioset+0x353/0x590
[10051.053658]  mpage_alloc+0x3b/0x240
[10051.054382]  do_mpage_readpage+0xddf/0x1ef0
[10051.055250]  mpage_readahead+0x264/0x500
[10051.056060]  read_pages+0x1c1/0xbf0
[10051.056758]  page_cache_ra_unbounded+0x4c2/0x6f0
[10051.057702]  do_page_cache_ra+0xda/0x110
[10051.058511]  force_page_cache_ra+0x23d/0x3d0
[10051.059373]  page_cache_sync_ra+0xca/0x300
[10051.060198]  generic_file_buffered_read+0xbea/0x2130
[10051.061195]  generic_file_read_iter+0x315/0x490
[10051.062189]  blkdev_read_iter+0x113/0x1b0
[10051.063015]  aio_read+0x2ad/0x450
[10051.063686]  io_submit_one+0xc8e/0x1d60
[10051.064467]  __se_sys_io_submit+0x125/0x350
[10051.065318]  do_syscall_64+0x2d/0x40
[10051.066082]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

[10051.067455] Freed by task 13307:
[10051.068136]  kasan_save_stack+0x19/0x40
[10051.068931]  kasan_set_track+0x1c/0x30
[10051.069726]  kasan_set_free_info+0x1b/0x30
[10051.070621]  __kasan_slab_free+0x111/0x160
[10051.071480]  kmem_cache_free+0x94/0x460
[10051.072256]  mempool_free+0xd6/0x320
[10051.072985]  bio_free+0xe0/0x130
[10051.073630]  bio_put+0xab/0xe0
[10051.074252]  bio_endio+0x3a6/0x5d0
[10051.074984]  blk_update_request+0x590/0x1370
[10051.075870]  scsi_end_request+0x7d/0x400
[10051.076667]  scsi_io_completion+0x1aa/0xe50
[10051.077503]  scsi_softirq_done+0x11b/0x240
[10051.078344]  blk_mq_complete_request+0xd4/0x120
[10051.079275]  scsi_mq_done+0xf0/0x200
[10051.080036]  virtscsi_vq_done+0xbc/0x150
[10051.080850]  vring_interrupt+0x179/0x390
[10051.081650]  __handle_irq_event_percpu+0xf7/0x490
[10051.082626]  handle_irq_event_percpu+0x7b/0x160
[10051.083527]  handle_irq_event+0xcc/0x170
[10051.084297]  handle_edge_irq+0x215/0xb20
[10051.085122]  asm_call_irq_on_stack+0xf/0x20
[10051.085986]  common_interrupt+0xae/0x120
[10051.086830]  asm_common_interrupt+0x1e/0x40

==================================================================

Bio will be checked at beginning of submit_bio_noacct(). If bio needs
to be throttled, it will start the timer and stop submit bio directly.
Bio will submit in blk_throtl_dispatch_work_fn() when the timer expires.
But in the current process, if bio is throttled, it will still set bio
issue->value by blkcg_bio_issue_init(). This is redundant and may cause
the above use-after-free.

CPU0                                   CPU1
submit_bio
submit_bio_noacct
  submit_bio_checks
    blk_throtl_bio()
      <=mod_timer(&sq->pending_timer
                                      blk_throtl_dispatch_work_fn
                                        submit_bio_noacct() <= bio have
                                        throttle tag, will throw directly
                                        and bio issue->value will be set
                                        here

                                      bio_endio()
                                      bio_put()
                                      bio_free() <= free this bio

    blkcg_bio_issue_init(bio)
      <= bio has been freed and
      will lead to UAF
  return BLK_QC_T_NONE

Fix this by remove extra blkcg_bio_issue_init.

Fixes: e439bedf (blkcg: consolidate bio_issue_init() to be a part of core)
Signed-off-by: Laibin Qiu <qiulaibin@huawei.com>
Link: https://lore.kernel.org/r/20211112093354.3581504-1-qiulaibin@huawei.com


Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

When BLKRESETZONE ioctl and data read race, the data read leaves stale
page cache. The commit e5113505 ("block: Discard page cache of zone
reset target range") added page cache truncation to avoid stale page
cache after the ioctl. However, the stale page cache still can be read
during the reset zone operation for the ioctl. To avoid the stale page
cache completely, hold invalidate_lock of the block device file mapping.

Fixes: e5113505 ("block: Discard page cache of zone reset target range")
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Cc: stable@vger.kernel.org # v5.15
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211111085238.942492-1-shinichiro.kawasaki@wdc.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

It is very annoying to have two block layer functions which share same
name, so rename blk_attempt_bio_merge in blk-mq.c as
blk_mq_attempt_bio_merge.

Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211111085134.345235-3-ming.lei@redhat.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

blk_mq_sched_bio_merge is only called from blk-mq.c:blk_attempt_bio_merge(),
which is called when queue usage counter is grabbed already:

1) blk_mq_get_new_requests()

2) blk_mq_get_request()
- cached request in current plug owns one queue usage counter

So don't grab ->q_usage_counter in blk_mq_sched_bio_merge(), and more
importantly this nest way causes hang in blk_mq_freeze_queue_wait().

Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211111085134.345235-2-ming.lei@redhat.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

The naming got changed as part of a revision of the patchset, but the
kerneldoc apparently never got updated. Fix it.

Reported-by: kernel test robot <lkp@intel.com>
Fixes: a2247f19 ("block: Add independent access ranges support")
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Now that we have done a spring cleaning on all drivers and added
error checking / handling, let's keep it that way and ensure
no new drivers fail to stick with it.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20211110002949.999380-1-mcgrof@kernel.org


Signed-off-by: Jens Axboe <axboe@kernel.dk>

kernel test robot reports that we now trigger some sparse warnings:

block/blk-mq.h:169:32: sparse: sparse: restricted req_flags_t degrades to integer
block/blk-mq.h:169:32: sparse: sparse: restricted req_flags_t degrades to integer
block/blk-mq.h:169:32: sparse: sparse: restricted req_flags_t degrades to integer

which is due to ->rq_flags being an unsigned int, rather than the
stronger type req_flags_t enum.

Change the type to req_flags_t to silence this warning.

Fixes: 56f8da64 ("block: add rq_flags to struct blk_mq_alloc_data")
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

When BLKZEROOUT ioctl and data read race, the data read leaves stale
page cache. To avoid the stale page cache, hold invalidate_lock of the
block device file mapping. The stale page cache is observed when
blktests test case block/009 is modified to call "blkdiscard -z" command
and repeated hundreds of times.

This patch can be applied back to the stable kernel version v5.15.y.
Rework is required for older stable kernels.

Fixes: 22dd6d35 ("block: invalidate the page cache when issuing BLKZEROOUT")
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Cc: stable@vger.kernel.org # v5.15
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20211109104723.835533-3-shinichiro.kawasaki@wdc.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

When BLKDISCARD ioctl and data read race, the data read leaves stale
page cache. To avoid the stale page cache, hold invalidate_lock of the
block device file mapping. The stale page cache is observed when
blktests test case block/009 is repeated hundreds of times.

This patch can be applied back to the stable kernel version v5.15.y
with slight patch edit. Rework is required for older stable kernels.

Fixes: 351499a1 ("block: Invalidate cache on discard v2")
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Cc: stable@vger.kernel.org # v5.15
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20211109104723.835533-2-shinichiro.kawasaki@wdc.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

Some drivers(NVMe, SCSI) need to call quiesce and unquiesce in pair, but it
is hard to switch to this style, so these drivers need one atomic flag for
helping to balance quiesce and unquiesce.

When quiesce is in-progress, the driver still needs to wait until
the quiesce is done, so add API of blk_mq_wait_quiesce_done() for
these drivers.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20211109071144.181581-2-ming.lei@redhat.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

We got UAF report on v5.10 as follows:
[ 1446.674930] ==================================================================
[ 1446.675970] BUG: KASAN: use-after-free in blk_mq_get_driver_tag+0x9a4/0xa90
[ 1446.676902] Read of size 8 at addr ffff8880185afd10 by task kworker/1:2/12348
[ 1446.677851]
[ 1446.678073] CPU: 1 PID: 12348 Comm: kworker/1:2 Not tainted 5.10.0-10177-gc9c81b1e346a #2
[ 1446.679168] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
[ 1446.680692] Workqueue: kthrotld blk_throtl_dispatch_work_fn
[ 1446.681448] Call Trace:
[ 1446.681800]  dump_stack+0x9b/0xce
[ 1446.682916]  print_address_description.constprop.6+0x3e/0x60
[ 1446.685999]  kasan_report.cold.9+0x22/0x3a
[ 1446.687186]  blk_mq_get_driver_tag+0x9a4/0xa90
[ 1446.687785]  blk_mq_dispatch_rq_list+0x21a/0x1d40
[ 1446.692576]  __blk_mq_do_dispatch_sched+0x394/0x830
[ 1446.695758]  __blk_mq_sched_dispatch_requests+0x398/0x4f0
[ 1446.698279]  blk_mq_sched_dispatch_requests+0xdf/0x140
[ 1446.698967]  __blk_mq_run_hw_queue+0xc0/0x270
[ 1446.699561]  __blk_mq_delay_run_hw_queue+0x4cc/0x550
[ 1446.701407]  blk_mq_run_hw_queue+0x13b/0x2b0
[ 1446.702593]  blk_mq_sched_insert_requests+0x1de/0x390
[ 1446.703309]  blk_mq_flush_plug_list+0x4b4/0x760
[ 1446.705408]  blk_flush_plug_list+0x2c5/0x480
[ 1446.708471]  blk_finish_plug+0x55/0xa0
[ 1446.708980]  blk_throtl_dispatch_work_fn+0x23b/0x2e0
[ 1446.711236]  process_one_work+0x6d4/0xfe0
[ 1446.711778]  worker_thread+0x91/0xc80
[ 1446.713400]  kthread+0x32d/0x3f0
[ 1446.714362]  ret_from_fork+0x1f/0x30
[ 1446.714846]
[ 1446.715062] Allocated by task 1:
[ 1446.715509]  kasan_save_stack+0x19/0x40
[ 1446.716026]  __kasan_kmalloc.constprop.1+0xc1/0xd0
[ 1446.716673]  blk_mq_init_tags+0x6d/0x330
[ 1446.717207]  blk_mq_alloc_rq_map+0x50/0x1c0
[ 1446.717769]  __blk_mq_alloc_map_and_request+0xe5/0x320
[ 1446.718459]  blk_mq_alloc_tag_set+0x679/0xdc0
[ 1446.719050]  scsi_add_host_with_dma.cold.3+0xa0/0x5db
[ 1446.719736]  virtscsi_probe+0x7bf/0xbd0
[ 1446.720265]  virtio_dev_probe+0x402/0x6c0
[ 1446.720808]  really_probe+0x276/0xde0
[ 1446.721320]  driver_probe_device+0x267/0x3d0
[ 1446.721892]  device_driver_attach+0xfe/0x140
[ 1446.722491]  __driver_attach+0x13a/0x2c0
[ 1446.723037]  bus_for_each_dev+0x146/0x1c0
[ 1446.723603]  bus_add_driver+0x3fc/0x680
[ 1446.724145]  driver_register+0x1c0/0x400
[ 1446.724693]  init+0xa2/0xe8
[ 1446.725091]  do_one_initcall+0x9e/0x310
[ 1446.725626]  kernel_init_freeable+0xc56/0xcb9
[ 1446.726231]  kernel_init+0x11/0x198
[ 1446.726714]  ret_from_fork+0x1f/0x30
[ 1446.727212]
[ 1446.727433] Freed by task 26992:
[ 1446.727882]  kasan_save_stack+0x19/0x40
[ 1446.728420]  kasan_set_track+0x1c/0x30
[ 1446.728943]  kasan_set_free_info+0x1b/0x30
[ 1446.729517]  __kasan_slab_free+0x111/0x160
[ 1446.730084]  kfree+0xb8/0x520
[ 1446.730507]  blk_mq_free_map_and_requests+0x10b/0x1b0
[ 1446.731206]  blk_mq_realloc_hw_ctxs+0x8cb/0x15b0
[ 1446.731844]  blk_mq_init_allocated_queue+0x374/0x1380
[ 1446.732540]  blk_mq_init_queue_data+0x7f/0xd0
[ 1446.733155]  scsi_mq_alloc_queue+0x45/0x170
[ 1446.733730]  scsi_alloc_sdev+0x73c/0xb20
[ 1446.734281]  scsi_probe_and_add_lun+0x9a6/0x2d90
[ 1446.734916]  __scsi_scan_target+0x208/0xc50
[ 1446.735500]  scsi_scan_channel.part.3+0x113/0x170
[ 1446.736149]  scsi_scan_host_selected+0x25a/0x360
[ 1446.736783]  store_scan+0x290/0x2d0
[ 1446.737275]  dev_attr_store+0x55/0x80
[ 1446.737782]  sysfs_kf_write+0x132/0x190
[ 1446.738313]  kernfs_fop_write_iter+0x319/0x4b0
[ 1446.738921]  new_sync_write+0x40e/0x5c0
[ 1446.739429]  vfs_write+0x519/0x720
[ 1446.739877]  ksys_write+0xf8/0x1f0
[ 1446.740332]  do_syscall_64+0x2d/0x40
[ 1446.740802]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 1446.741462]
[ 1446.741670] The buggy address belongs to the object at ffff8880185afd00
[ 1446.741670]  which belongs to the cache kmalloc-256 of size 256
[ 1446.743276] The buggy address is located 16 bytes inside of
[ 1446.743276]  256-byte region [ffff8880185afd00, ffff8880185afe00)
[ 1446.744765] The buggy address belongs to the page:
[ 1446.745416] page:ffffea0000616b00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x185ac
[ 1446.746694] head:ffffea0000616b00 order:2 compound_mapcount:0 compound_pincount:0
[ 1446.747719] flags: 0x1fffff80010200(slab|head)
[ 1446.748337] raw: 001fffff80010200 ffffea00006a3208 ffffea000061bf08 ffff88801004f240
[ 1446.749404] raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
[ 1446.750455] page dumped because: kasan: bad access detected
[ 1446.751227]
[ 1446.751445] Memory state around the buggy address:
[ 1446.752102]  ffff8880185afc00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 1446.753090]  ffff8880185afc80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 1446.754079] >ffff8880185afd00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 1446.755065]                          ^
[ 1446.755589]  ffff8880185afd80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 1446.756574]  ffff8880185afe00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 1446.757566] ==================================================================

Flag 'BLK_MQ_F_TAG_QUEUE_SHARED' will be set if the second device on the
same host initializes it's queue successfully. However, if the second
device failed to allocate memory in blk_mq_alloc_and_init_hctx() from
blk_mq_realloc_hw_ctxs() from blk_mq_init_allocated_queue(),
__blk_mq_free_map_and_rqs() will be called on error path, and if
'BLK_MQ_TAG_HCTX_SHARED' is not set, 'tag_set->tags' will be freed
while it's still used by the first device.

To fix this issue we move release newly allocated hardware context from
blk_mq_realloc_hw_ctxs to __blk_mq_update_nr_hw_queues. As there is needn't to
release hardware context in blk_mq_init_allocated_queue.

Fixes: 868f2f0b ("blk-mq: dynamic h/w context count")
Signed-off-by: Ye Bin <yebin10@huawei.com>
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211108074019.1058843-1-yebin10@huawei.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

We have new helpers for this, use them rather than the slower inode
size reads. This makes the read/write path consistent with most of
the rest of block as well.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/a72767cd-3c6d-47f7-80f4-aa025a17b2cb@kernel.dk


Signed-off-by: Jens Axboe <axboe@kernel.dk>

Commit 83cbce95 ("block: add error handling for device_add_disk /
add_disk") added error handling to device_add_disk(), however the goto
label for the kobject_create_and_add() failure did not set the return
value correctly, and so we can end up in a situation where
kobject_create_and_add() fails but we report success.

Fixes: 83cbce95 ("block: add error handling for device_add_disk / add_disk")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211103164023.1384821-1-mcgrof@kernel.org


[axboe: fold in followup fix from Wu Bo <wubo40@huawei.com>]
Signed-off-by: Jens Axboe <axboe@kernel.dk>

If we're driving multiple devices, we could have pre-populated the cache
for a different device. Ensure that the empty request matches the current
queue.

Fixes: 47c122e3 ("block: pre-allocate requests if plug is started and is a batch")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Retain the old logic for the fops based submit, but for our internal
blk_mq_submit_bio(), move the queue entering logic into the core
function itself.

We need to be a bit careful if going into the scheduler, as a scheduler
or queue mappings can arbitrarily change before we have entered the queue.
Have the bio scheduler mapping do that separately, it's a very cheap
operation compared to actually doing merging locking and lookups.

Reviewed-by: Christoph Hellwig <hch@lst.de>
[axboe: update to check merge post submit_bio_checks() doing remap...]
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Just a prep patch for shifting the queue enter logic. This moves the
expected fast path inline, and leaves __bio_queue_enter() as an
out-of-line function call. We don't want to inline the latter, as it's
mostly slow path code.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

This is in preparation for a fix, but serves as a cleanup as well moving
the cached vs regular alloc logic out of blk_mq_submit_bio().

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Requests that were stored in the cache deliberately didn't hold an enter
reference to the queue, instead we grabbed one every time we pulled a
request out of there. That made for awkward logic on freeing the remainder
of the cached list, if needed, where we had to artificially raise the
queue usage count before each free.

Grab references up front for cached plug requests. That's safer, and also
more efficient.

Fixes: 47c122e3 ("block: pre-allocate requests if plug is started and is a batch")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

__register_blkdev() is used to register a probe callback, and
that callback is typically used to call add_disk(). Now that
we are able to capture errors for add_disk(), we need to fix
those probe calls where add_disk() fails and clean up resources.

We don't extend the probe call to return the error given:

1) we'd have to always special-case the case where the disk
   was already present, as otherwise concurrent requests to
   open an existing block device would fail, and this would be
   a userspace visible change
2) the error from ilookup() on blkdev_get_no_open() is sufficient
3) The only thing the probe call is used for is to support
   pre-devtmpfs, pre-udev semantics that want to create disks when
   their pre-created device node is accessed, and so we don't care
   for failures on probe there.

Expand documentation for the probe callback to ensure users cleanup
resources if add_disk() is used and to clarify this interface may be
removed in the future.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/20211103230437.1639990-12-mcgrof@kernel.org


Signed-off-by: Jens Axboe <axboe@kernel.dk>

In case of shared tags and none io sched, batched completion still may
be run into, and hctx->nr_active is accounted when getting driver tag,
so it has to be updated in blk_mq_end_request_batch().

Otherwise, hctx->nr_active may become same with queue depth, then
hctx_may_queue() always return false, then io hang is caused.

Fixes the issue by updating the counter in batched way.

Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Fixes: f794f335 ("block: add support for blk_mq_end_request_batch()")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211102153619.3627505-4-ming.lei@redhat.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

Looks it is missed so add it.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211102133502.3619184-3-ming.lei@redhat.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

It is obvious that io merge can't be done between two different queues, so
just try to run io merge in case of same queue.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20211102133502.3619184-2-ming.lei@redhat.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

It's not safe to do this before blk_queue_enter(), as the scheduler state
could have changed in between. Hence move the RQF_ELV setting into the
allocators, where we know the queue is already entered.

Suggested-by: Ming Lei <ming.lei@redhat.com>
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Reported-by: Steffen Maier <maier@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

A previous commit fixed up the condition for doing direct issue, but that
left the 'from_schedule' argument dead inside the branch. Replace it with
'false'.

Fixes: ff155223 ("blk-mq: don't issue request directly in case that current is to be blocked")
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>