This function was transitioned from returning NVMe status codes to
returning traditional kernel error codes.  However, this particular
return now accidentally returns positive error codes like ENOMEM instead
of negative -ENOMEM.

Fixes: b0ef1b11 ("nvme-auth: don't use NVMe status codes")
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Bring back the check of the Identify Namespace return value for the
legacy NVMe 1.0-style sequential scanning.  While NVMe 1.0 does not
support namespace management, there are "modern" cloud solutions like
Google Cloud Platform that claim the obsolete 1.0 compliance for no
good reason while supporting proprietary sideband namespace management.

Fixes: 1a893c2b ("nvme: refactor namespace probing")
Reported-by: Nils Hanke <nh@edgeless.systems>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Tested-by: Nils Hanke <nh@edgeless.systems>

The log entries are stored in le32, so use appropriate byte swapping
macros.
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/oe-kbuild-all/202302242222.PevBhzvC-lkp@intel.com/Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Wei reports a crash with an application using polled IO:

PGD 14265e067 P4D 14265e067 PUD 47ec50067 PMD 0
Oops: 0000 [#1] SMP
CPU: 0 PID: 21915 Comm: iocore_0 Kdump: loaded Tainted: G S                5.12.0-0_fbk12_clang_7346_g1bb6f2e7058f #1
Hardware name: Wiwynn Delta Lake MP T8/Delta Lake-Class2, BIOS Y3DLM08 04/10/2022
RIP: 0010:bio_poll+0x25/0x200
Code: 0f 1f 44 00 00 0f 1f 44 00 00 55 41 57 41 56 41 55 41 54 53 48 83 ec 28 65 48 8b 04 25 28 00 00 00 48 89 44 24 20 48 8b 47 08 <48> 8b 80 70 02 00 00 4c 8b 70 50 8b 6f 34 31 db 83 fd ff 75 25 65
RSP: 0018:ffffc90005fafdf8 EFLAGS: 00010292
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 74b43cd65dd66600
RDX: 0000000000000003 RSI: ffffc90005fafe78 RDI: ffff8884b614e140
RBP: ffff88849964df78 R08: 0000000000000000 R09: 0000000000000008
R10: 0000000000000000 R11: 0000000000000000 R12: ffff88849964df00
R13: ffffc90005fafe78 R14: ffff888137d3c378 R15: 0000000000000001
FS:  00007fd195000640(0000) GS:ffff88903f400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000270 CR3: 0000000466121001 CR4: 00000000007706f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
 iocb_bio_iopoll+0x1d/0x30
 io_do_iopoll+0xac/0x250
 __se_sys_io_uring_enter+0x3c5/0x5a0
 ? __x64_sys_write+0x89/0xd0
 do_syscall_64+0x2d/0x40
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x94f225d
Code: 24 cc 00 00 00 41 8b 84 24 d0 00 00 00 c1 e0 04 83 e0 10 41 09 c2 8b 33 8b 53 04 4c 8b 43 18 4c 63 4b 0c b8 aa 01 00 00 0f 05 <85> c0 0f 88 85 00 00 00 29 03 45 84 f6 0f 84 88 00 00 00 41 f6 c7
RSP: 002b:00007fd194ffcd88 EFLAGS: 00000202 ORIG_RAX: 00000000000001aa
RAX: ffffffffffffffda RBX: 00007fd194ffcdc0 RCX: 00000000094f225d
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000007
RBP: 00007fd194ffcdb0 R08: 0000000000000000 R09: 0000000000000008
R10: 0000000000000001 R11: 0000000000000202 R12: 00007fd269d68030
R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000000

which is due to bio->bi_bdev being NULL. This can happen if we have two
tasks doing polled IO, and task B ends up completing IO from task A if
they are sharing a poll queue. If task B completes the IO and puts the
bio into our cache, then it can allocate that bio again before task A
is done polling for it. As that would necessitate a preempt between the
two tasks, it's enough to just be a bit more careful in checking for
whether or not bio->bi_bdev is NULL.
Reported-and-tested-by: Wei Zhang <wzhang@meta.com>
Cc: stable@vger.kernel.org
Fixes: be4d234d ("bio: add allocation cache abstraction")
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

This isn't strictly needed in terms of correctness, but it does allow
polling to know if the bio has been put already by a different task
and hence avoid polling something that we don't need to.

Cc: stable@vger.kernel.org
Fixes: be4d234d ("bio: add allocation cache abstraction")
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

In loop_set_status_from_info(), lo->lo_offset and lo->lo_sizelimit should
be checked before reassignment, because if an overflow error occurs, the
original correct value will be changed to the wrong value, and it will not
be changed back.

More, the original patch did not solve the problem, the value was set and
ioctl returned an error, but the subsequent io used the value in the loop
driver, which still caused an alarm:

loop_handle_cmd
 do_req_filebacked
  loff_t pos = ((loff_t) blk_rq_pos(rq) << 9) + lo->lo_offset;
  lo_rw_aio
   cmd->iocb.ki_pos = pos

Fixes: c490a0b5 ("loop: Check for overflow while configuring loop")
Signed-off-by: Zhong Jinghua <zhongjinghua@huawei.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20230221095027.3656193-1-zhongjinghua@huaweicloud.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

sizeof(struct ublksrv_io_cmd) is 16bytes, which can be held in 64byte SQE,
so not necessary to check IO_URING_F_SQE128.

With this change, we get chance to save half SQ ring memory.

Fixed: 71f28f31 ("ublk_drv: add io_uring based userspace block driver")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20230220041413.1524335-1-ming.lei@redhat.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

bdev_get_queue() never returns NULL. Several commits [1][2] have been made
before to remove such superfluous checks, but some still remained.

For places where bdev_get_queue() is called solely for NULL checks, it is
removed entirely.

[1] commit ec9fd2a1 ("blk-lib: don't check bdev_get_queue() NULL check")
[2] commit fea127b3 ("block: remove superfluous check for request queue in bdev_is_zoned()")
Signed-off-by: Juhyung Park <qkrwngud825@gmail.com>
Reviewed-by: Pankaj Raghav <p.raghav@samsung.com>
Link: https://lore.kernel.org/r/20230203024029.48260-1-qkrwngud825@gmail.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

Group some variables based on their sizes to reduce hole and avoid padding.
On x86_64, this shrinks the size of 'struct blk_mq_tag_set'
from 304 to 296 bytes.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/6f249f9b02a3490283ef0278096556de41aa0cf0.1676626130.git.christophe.jaillet@wanadoo.frSigned-off-by: Jens Axboe <axboe@kernel.dk>

As explained in commit 36369f46 ("block: Do not reread partition table
on exclusively open device"), reread partition on the device that is
exclusively opened by someone else is problematic.

This patch will make sure partition scan will only be proceed if current
thread open the device exclusively, or the device is not opened
exclusively, and in the later case, other scanners and exclusive openers
will be blocked temporarily until partition scan is done.

Fixes: 10c70d95 ("block: remove the bd_openers checks in blk_drop_partitions")
Cc: <stable@vger.kernel.org>
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230217022200.3092987-3-yukuai1@huaweicloud.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

This reverts commit 36369f46.

This patch can't fix the problem in a corner case that device can be
opened exclusively after the checking and before blkdev_get_by_dev().
We'll use a new solution to fix the problem in the next patch, and
the new solution doesn't need to change apis.
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Acked-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230217022200.3092987-2-yukuai1@huaweicloud.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

Not every OPAL drive supports SUM (Single User Mode), so report this
information to userspace via the get-status ioctl so that we can adjust
the formatting options accordingly.
Tested on a kingston drive (which supports it) and a samsung one
(which does not).
Signed-off-by: Luca Boccassi <bluca@debian.org>
Link: https://lore.kernel.org/r/20230210010612.28729-1-luca.boccassi@gmail.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

Unconditionally calling radix_tree_preload_end() results in a OOPS
message as the preload is only conditionally called for
gfpflags_allow_blocking().

[   20.267323] BUG: using smp_processor_id() in preemptible [00000000] code: fio/416
[   20.267837] caller is brd_insert_page.part.0+0xbe/0x190 [brd]
[   20.269436] Call Trace:
[   20.269598]  <TASK>
[   20.269742]  dump_stack_lvl+0x32/0x50
[   20.269982]  check_preemption_disabled+0xd1/0xe0
[   20.270289]  brd_insert_page.part.0+0xbe/0x190 [brd]
[   20.270664]  brd_submit_bio+0x33f/0xf40 [brd]

Use radix_tree_maybe_preload() which does preload only if
gfpflags_allow_blocking() is true but also takes the lock. Therefore,
unconditionally calling radix_tree_preload_end() should not create any
issues and the message disappears.

Fixes: 6ded703c ("brd: check for REQ_NOWAIT and set correct page allocation mask")
Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
Link: https://lore.kernel.org/r/20230217121442.33914-1-p.raghav@samsung.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

kernel test robot complains about a type mismatch:

   block/blk-merge.c:984:42: sparse:     expected restricted blk_opf_t const [usertype] ff
   block/blk-merge.c:984:42: sparse:     got unsigned int
   block/blk-merge.c:1010:42: sparse: sparse: incorrect type in initializer (different base types) @@     expected restricted blk_opf_t const [usertype] ff @@     got unsigned int @@
   block/blk-merge.c:1010:42: sparse:     expected restricted blk_opf_t const [usertype] ff
   block/blk-merge.c:1010:42: sparse:     got unsigned int

because bio_failfast() is return an unsigned int rather than the
appropriate blk_opt_f type. Fix it up.

Fixes: 3ce6a115 ("block: sync mixed merged request's failfast with 1st bio's")
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/oe-kbuild-all/202302170743.GXypM9Rt-lkp@intel.com/Signed-off-by: Jens Axboe <axboe@kernel.dk>

Make sure to copy the flags when a bio_integrity_payload is cloned.
Otherwise per-I/O properties such as IP checksum flag will not be
passed down to the HBA driver. Since the integrity buffer is owned by
the original bio, the BIP_BLOCK_INTEGRITY flag needs to be masked off
to avoid a double free in the completion path.

Fixes: aae7df50 ("block: Integrity checksum flag")
Fixes: b1f01388 ("block: Relocate bio integrity flags")
Reported-by: Saurav Kashyap <skashyap@marvell.com>
Tested-by: Saurav Kashyap <skashyap@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20230215171801.21062-1-martin.petersen@oracle.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

In the current code, io statistics are missing for cgroup when bio
was throttled by blk-throttle. Fix it by moving the unreaching code
to submit_bio_noacct_nocheck.

Fixes: 3f98c753 ("block: don't check bio in blk_throtl_dispatch_work_fn")
Signed-off-by: Jinke Han <hanjinke.666@bytedance.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Acked-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230216032250.74230-1-hanjinke.666@bytedance.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

By default, non-mq drivers do not support nowait. This causes io_uring
to use a slower path as the driver cannot be trust not to block. brd
can safely set the nowait flag, as worst case all it does is a NOIO
allocation.

For io_uring, this makes a substantial difference. Before:

submitter=0, tid=453, file=/dev/ram0, node=-1
polled=0, fixedbufs=1/0, register_files=1, buffered=0, QD=128
Engine=io_uring, sq_ring=128, cq_ring=128
IOPS=440.03K, BW=1718MiB/s, IOS/call=32/31
IOPS=428.96K, BW=1675MiB/s, IOS/call=32/32
IOPS=442.59K, BW=1728MiB/s, IOS/call=32/31
IOPS=419.65K, BW=1639MiB/s, IOS/call=32/32
IOPS=426.82K, BW=1667MiB/s, IOS/call=32/31

and after:

submitter=0, tid=354, file=/dev/ram0, node=-1
polled=0, fixedbufs=1/0, register_files=1, buffered=0, QD=128
Engine=io_uring, sq_ring=128, cq_ring=128
IOPS=3.37M, BW=13.15GiB/s, IOS/call=32/31
IOPS=3.45M, BW=13.46GiB/s, IOS/call=32/31
IOPS=3.43M, BW=13.42GiB/s, IOS/call=32/32
IOPS=3.43M, BW=13.39GiB/s, IOS/call=32/31
IOPS=3.43M, BW=13.38GiB/s, IOS/call=32/31

or about an 8x in difference. Now that brd is prepared to deal with
REQ_NOWAIT reads/writes, mark it as supporting that.

Cc: stable@vger.kernel.org # 5.10+
Link: https://lore.kernel.org/linux-block/20230203103005.31290-1-p.raghav@samsung.com/Signed-off-by: Jens Axboe <axboe@kernel.dk>

If REQ_NOWAIT is set, then do a non-blocking allocation if the operation
is a write and we need to insert a new page. Currently REQ_NOWAIT cannot
be set as the queue isn't marked as supporting nowait, this change is in
preparation for allowing that.

radix_tree_preload() warns on attempting to call it with an allocation
mask that doesn't allow blocking. While that warning could arguably
be removed, we need to handle radix insertion failures anyway as they
are more likely if we cannot block to get memory.

Remove legacy BUG_ON()'s and turn them into proper errors instead, one
for the allocation failure and one for finding a page that doesn't
match the correct index.

Cc: stable@vger.kernel.org # 5.10+
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

It currently returns a page, but callers just check for NULL/page to
gauge success. Clean this up and return the appropriate error directly
instead.

Cc: stable@vger.kernel.org # 5.10+
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

We support mixed merge for requests/bios with different fastfail
settings. When request fails, each time we only handle the portion
with same failfast setting, then bios with failfast can be failed
immediately, and bios without failfast can be retried.

The idea is pretty good, but the current implementation has several
defects:

1) initially RA bio doesn't set failfast, however bio merge code
doesn't consider this point, and just check its failfast setting for
deciding if mixed merge is required. Fix this issue by adding helper
of bio_failfast().

2) when merging bio to request front, if this request is mixed
merged, we have to sync request's faifast setting with 1st bio's
failfast. Fix it by calling blk_update_mixed_merge().

3) when merging bio to request back, if this request is mixed
merged, we have to mark the bio as failfast, because blk_update_request
simply updates request failfast with 1st bio's failfast. Fix
it by calling blk_update_mixed_merge().

Fixes one normal EXT4 READ IO failure issue, because it is observed
that the normal READ IO is merged with RA IO, and the mixed merged
request has different failfast setting with 1st bio's, so finally
the normal READ IO doesn't get retried.

Cc: Tejun Heo <tj@kernel.org>
Fixes: 80a761fd ("block: implement mixed merge of different failfast requests")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20230209125527.667004-1-ming.lei@redhat.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

Pull NVMe fixes from Christoph:

"nvme fixes for Linux 6.3

 - fix and cleanup freeing single sgl (Keith Busch)"

* tag 'nvme-6.3-2023-02-15' of git://git.infradead.org/nvme:
  nvme-pci: remove iod use_sgls
  nvme-pci: fix freeing single sgl

This reverts commit 84d7d462.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230214183308.1658775-6-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

This reverts commit 821e840c08ad83736eced4037cdad864e95e2584.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230214183308.1658775-5-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

This reverts commit 178fa7d4.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230214183308.1658775-4-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

This reverts commit c43332fe as it is not
needed without moving to disk references in the blkg.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230214183308.1658775-3-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

This reverts commit 3f13ab7c as a patch
it depends on caused a few problems.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230214183308.1658775-2-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

It's not used anywhere anymore, so remove it.
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

There may only be a single DMA mapped entry from multiple physical
segments, which means we don't allocate a separte SGL list. Check the
number of allocations prior to know if we need to free something.

Freeing a single list allocation is the same for both PRP and SGL
usages, so we don't need to check the use_sgl flag anymore.

Fixes: 01df742d ("nvme-pci: remove SGL segment descriptors")
Reported-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Niklas Schnelle <schnelle@linux.ibm.com>

Currently, uring_cmd with UBLK_IO_FETCH_REQ or
UBLK_IO_COMMIT_AND_FETCH_REQ is always checked whether
userspace server has provided IO buffer even flag
UBLK_F_NEED_GET_DATA is configured.

This is a excessive check. If UBLK_F_NEED_GET_DATA is
configured, FETCH_RQ doesn't need to provide IO buffer;
COMMIT_AND_FETCH_REQ also doesn't need to do that if
the IO type is not READ.

Check ub_cmd->addr together with ublk_need_get_data()
and IO type in ublk_ch_uring_cmd().

With this fix, userspace server doesn't need to preserve
buffers for every ublk_io when flag UBLK_F_NEED_GET_DATA
is configured, in order to save memory.
Signed-off-by: Liu Xiaodong <xiaodong.liu@intel.com>
Fixes: c86019ff ("ublk_drv: add support for UBLK_IO_NEED_GET_DATA")
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20230210141356.112321-1-xiaodong.liu@intel.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

`dasd_reserve_req` is allocated before `dasd_vol_info_req`, and it
also needs to be freed before the error returns, just like the other
cases in this function.

Fixes: 9e12e54c ("s390/dasd: Handle out-of-space constraint")
Signed-off-by: Qiheng Lin <linqiheng@huawei.com>
Link: https://lore.kernel.org/r/20221208133809.16796-1-linqiheng@huawei.comSigned-off-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20230210000253.1644903-3-sth@linux.ibm.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

This does not fix a real bug, since virtual addresses
are currently indentical to physical ones.
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Stefan Haberland <sth@linux.ibm.com>
Link: https://lore.kernel.org/r/20230210000253.1644903-2-sth@linux.ibm.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

Commit b99182c5 ("bio: add pcpu caching for non-polling bio_put")
removed the code that uses this constant. Hence also remove the constant
itself.

Cc: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20230209230135.3475829-1-bvanassche@acm.orgSigned-off-by: Jens Axboe <axboe@kernel.dk>

Since commit ee6d3dd4 ("driver core: make kobj_type constant.")
the driver core allows the usage of const struct kobj_type.

Take advantage of this to constify the structure definitions to prevent
modification at runtime.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20230208-kobj_type-block-v1-1-0b3eafd7d983@weissschuh.netSigned-off-by: Jens Axboe <axboe@kernel.dk>

It checks if plug->cached_rq is empty before merging bio. But the merge action
doesn't have relationship with plug->cached_rq, it trys to merge bio with
requests within plug->mq_list. Now it checks if ->cached_rq is empty before
merging bio. If it's empty, it will miss the merge chances. So move the merge
function before checking ->cached_rq.
Signed-off-by: Xiao Ni <xni@redhat.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20230209031930.27354-1-xni@redhat.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

It turns out this was too soon.  blkg_conf_prep does to funky locking games
with the queue lock for this to work properly.

This reverts commit 27b642b0.
Reported-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230209053523.437927-1-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

While del_gendisk ensures there is no outstanding I/O on the queue,
it can't prevent block layer users from building new I/O.

This leads to a NULL ->root_blkg reference in bio_associate_blkg when
allocating a new bio on a shut down file system.  Delay freeing the
blk-cgroup subsystems from del_gendisk until disk_release to make
sure the blkg and throttle information is still avaіlable for bio
submitters, even if those bios will immediately fail.

This now can cause a case where disk_release is called on a disk
that hasn't been added.  That's mostly harmless, except for a case
in blk_throttl_exit that now needs to check for a NULL ->td pointer.

Fixes: 178fa7d4 ("blk-cgroup: delay blk-cgroup initialization until add_disk")
Reported-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20230208063514.171485-1-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

Merge branch 'md-next' of https://git.kernel.org/pub/scm/linux/kernel/git/song/md into for-6.3/block

Pull MD fix from Song:

"This commit fixes a rare crash during the takeover process."

* 'md-next' of https://git.kernel.org/pub/scm/linux/kernel/git/song/md:
  md: account io_acct_set usage with active_io

io_acct_set was enabled for raid0/raid5 io accounting. bios that contain
md_io_acct are allocated in the i/o path. There isn't a good method to
monitor if these bios are all finished and freed. In the takeover process,
io_acct_set (which is used for bios with md_io_acct) need to be freed.
However, if some bios finish after io_acct_set is freed, it may trigger
the following panic:

[ 6973.767999] RIP: 0010:mempool_free+0x52/0x80
[ 6973.786098] Call Trace:
[ 6973.786549]  md_end_io_acct+0x31/0x40
[ 6973.787227]  blk_update_request+0x224/0x380
[ 6973.787994]  blk_mq_end_request+0x1a/0x130
[ 6973.788739]  blk_complete_reqs+0x35/0x50
[ 6973.789456]  __do_softirq+0xd7/0x2c8
[ 6973.790114]  ? sort_range+0x20/0x20
[ 6973.790763]  run_ksoftirqd+0x2a/0x40
[ 6973.791400]  smpboot_thread_fn+0xb5/0x150
[ 6973.792114]  kthread+0x10b/0x130
[ 6973.792724]  ? set_kthread_struct+0x50/0x50
[ 6973.793491]  ret_from_fork+0x1f/0x40

Fix this by increasing and decreasing active_io for each bio with
md_io_acct so that mddev_suspend() will wait until all bios from
io_acct_set finish before freeing io_acct_set.
Reported-by: Fine Fan <ffan@redhat.com>
Signed-off-by: Xiao Ni <xni@redhat.com>
Signed-off-by: Song Liu <song@kernel.org>

Inside ublk_ctrl_del_dev(), when the device is removed, we wait
until the device number is freed with holding global lock of
ublk_ctl_mutex, this way isn't friendly from user viewpoint:

1) if device is in-use, the current delete command hangs in
ublk_ctrl_del_dev(), and user can't break from the handling
because wait_event() is used

2) global lock is held, so any new device can't be added and
other old devices can't be removed.

Improve the deleting handling by the following way, suggested by
Nadav:

1) wait without holding the global lock

2) replace wait_event() with wait_event_interruptible()
Reported-by: Nadav Amit <nadav.amit@gmail.com>
Suggested-by: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20230207150700.545530-1-ming.lei@redhat.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

After commit dfd6200a ("blk-cgroup: support to track if policy is
online"), there is no need to do this again in bfq.

However, 'pd->online' is not protected by 'bfqd->lock', in order to make
sure bfq won't see that 'pd->online' is still set after bfq_pd_offline(),
clear it before bfq_pd_offline() is called. This is fine because other
polices doesn't use 'pd->online' and bfq_pd_offline() will move active
bfqq to root cgroup anyway.
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230202134913.2364549-1-yukuai1@huaweicloud.comSigned-off-by: Jens Axboe <axboe@kernel.dk>