It should use disk_stack_limits to get a proper max_discard_sectors
rather than setting a value by stack drivers.

And there is a bug. If all member disks are rotational devices,
raid0/raid10 set max_discard_sectors. So the member devices are
not ssd/nvme, but raid0/raid10 export the wrong value. It reports
warning messages in function __blkdev_issue_discard when mkfs.xfs
like this:

[ 4616.022599] ------------[ cut here ]------------
[ 4616.027779] WARNING: CPU: 4 PID: 99634 at block/blk-lib.c:50 __blkdev_issue_discard+0x16a/0x1a0
[ 4616.140663] RIP: 0010:__blkdev_issue_discard+0x16a/0x1a0
[ 4616.146601] Code: 24 4c 89 20 31 c0 e9 fe fe ff ff c1 e8 09 8d 48 ff 4c 89 f0 4c 09 e8 48 85 c1 0f 84 55 ff ff ff b8 ea ff ff ff e9 df fe ff ff <0f> 0b 48 8d 74 24 08 e8 ea d6 00 00 48 c7 c6 20 1e 89 ab 48 c7 c7
[ 4616.167567] RSP: 0018:ffffaab88cbffca8 EFLAGS: 00010246
[ 4616.173406] RAX: ffff9ba1f9e44678 RBX: 0000000000000000 RCX: ffff9ba1c9792080
[ 4616.181376] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff9ba1c9792080
[ 4616.189345] RBP: 0000000000000cc0 R08: ffffaab88cbffd10 R09: 0000000000000000
[ 4616.197317] R10: 0000000000000012 R11: 0000000000000000 R12: 0000000000000000
[ 4616.205288] R13: 0000000000400000 R14: 0000000000000cc0 R15: ffff9ba1c9792080
[ 4616.213259] FS:  00007f9a5534e980(0000) GS:ffff9ba1b7c80000(0000) knlGS:0000000000000000
[ 4616.222298] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 4616.228719] CR2: 000055a390a4c518 CR3: 0000000123e40006 CR4: 00000000001706e0
[ 4616.236689] Call Trace:
[ 4616.239428]  blkdev_issue_discard+0x52/0xb0
[ 4616.244108]  blkdev_common_ioctl+0x43c/0xa00
[ 4616.248883]  blkdev_ioctl+0x116/0x280
[ 4616.252977]  __x64_sys_ioctl+0x8a/0xc0
[ 4616.257163]  do_syscall_64+0x5c/0x90
[ 4616.261164]  ? handle_mm_fault+0xc5/0x2a0
[ 4616.265652]  ? do_user_addr_fault+0x1d8/0x690
[ 4616.270527]  ? do_syscall_64+0x69/0x90
[ 4616.274717]  ? exc_page_fault+0x62/0x150
[ 4616.279097]  entry_SYSCALL_64_after_hwframe+0x63/0xcd
[ 4616.284748] RIP: 0033:0x7f9a55398c6b
Signed-off-by: NXiao Ni <xni@redhat.com>
Reported-by: NYi Zhang <yi.zhang@redhat.com>
Reviewed-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NSong Liu <song@kernel.org>

Currently, wait_barrier() will hold 'resync_lock' to read 'conf->barrier',
and io can't be dispatched until 'barrier' is dropped.

Since holding the 'barrier' is not common, convert 'resync_lock' to use
seqlock so that holding lock can be avoided in fast path.
Signed-off-by: NYu Kuai <yukuai3@huawei.com>
Reviewed-and-Tested-by: NLogan Gunthorpe <logang@deltatee.com>
Signed-off-by: NSong Liu <song@kernel.org>

'conf->barrier' is protected by 'conf->resync_lock', reading
'conf->barrier' without holding the lock is wrong.
Signed-off-by: NYu Kuai <yukuai3@huawei.com>
Reviewed-by: NLogan Gunthorpe <logang@deltatee.com>
Acked-by: NGuoqing Jiang <guoqing.jiang@linux.dev>
Signed-off-by: NSong Liu <song@kernel.org>

Currently, wake_up() is called unconditionally in fast path such as
raid10_make_request(), which will cause lock contention under high
concurrency:

raid10_make_request
 wake_up
  __wake_up_common_lock
   spin_lock_irqsave

Improve performance by only call wake_up() if waitqueue is not empty
in allow_barrier() and raid10_make_request().
Signed-off-by: NYu Kuai <yukuai3@huawei.com>
Reviewed-by: NLogan Gunthorpe <logang@deltatee.com>
Acked-by: NGuoqing Jiang <guoqing.jiang@linux.dev>
Signed-off-by: NSong Liu <song@kernel.org>

For the case nowait in wait_barrier(), there is no point to increase
nr_waiting and then decrease it.
Signed-off-by: NYu Kuai <yukuai3@huawei.com>
Reviewed-by: NLogan Gunthorpe <logang@deltatee.com>
Acked-by: NGuoqing Jiang <guoqing.jiang@linux.dev>
Signed-off-by: NSong Liu <song@kernel.org>

Currently the nasty condition in wait_barrier() is hard to read. This
patch factors out the condition into a function.

There are no functional changes.
Signed-off-by: NYu Kuai <yukuai3@huawei.com>
Acked-by: NPaul Menzel <pmenzel@molgen.mpg.de>
Reviewed-by: NLogan Gunthorpe <logang@deltatee.com>
Acked-by: NGuoqing Jiang <guoqing.jiang@linux.dev>
Signed-off-by: NSong Liu <song@kernel.org>

With W=1, compiler complains.

drivers/md/raid10.c:1983: warning: bad line:
Signed-off-by: NGuoqing Jiang <guoqing.jiang@linux.dev>
Signed-off-by: NSong Liu <song@kernel.org>

Fix the following sparse warning:

drivers/md/raid10.c:2647:60: sparse: sparse: incorrect type in argument 5 (different base types) @@     expected restricted blk_opf_t [usertype] opf @@     got int rw @@

This patch does not change any functionality since REQ_OP_READ = READ = 0
and since REQ_OP_WRITE = WRITE = 1.

Cc: Rong A Chen <rong.a.chen@intel.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Paul Menzel <pmenzel@molgen.mpg.de>
Fixes: 4ce4c73f ("md/core: Combine two sync_page_io() arguments")
Reported-by: Nkernel test robot <lkp@intel.com>
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Signed-off-by: NSong Liu <song@kernel.org>

There's a KASAN warning in raid10_remove_disk when running the lvm
test lvconvert-raid-reshape.sh. We fix this warning by verifying that the
value "number" is valid.

BUG: KASAN: slab-out-of-bounds in raid10_remove_disk+0x61/0x2a0 [raid10]
Read of size 8 at addr ffff889108f3d300 by task mdX_raid10/124682

CPU: 3 PID: 124682 Comm: mdX_raid10 Not tainted 5.19.0-rc6 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x34/0x44
 print_report.cold+0x45/0x57a
 ? __lock_text_start+0x18/0x18
 ? raid10_remove_disk+0x61/0x2a0 [raid10]
 kasan_report+0xa8/0xe0
 ? raid10_remove_disk+0x61/0x2a0 [raid10]
 raid10_remove_disk+0x61/0x2a0 [raid10]
Buffer I/O error on dev dm-76, logical block 15344, async page read
 ? __mutex_unlock_slowpath.constprop.0+0x1e0/0x1e0
 remove_and_add_spares+0x367/0x8a0 [md_mod]
 ? super_written+0x1c0/0x1c0 [md_mod]
 ? mutex_trylock+0xac/0x120
 ? _raw_spin_lock+0x72/0xc0
 ? _raw_spin_lock_bh+0xc0/0xc0
 md_check_recovery+0x848/0x960 [md_mod]
 raid10d+0xcf/0x3360 [raid10]
 ? sched_clock_cpu+0x185/0x1a0
 ? rb_erase+0x4d4/0x620
 ? var_wake_function+0xe0/0xe0
 ? psi_group_change+0x411/0x500
 ? preempt_count_sub+0xf/0xc0
 ? _raw_spin_lock_irqsave+0x78/0xc0
 ? __lock_text_start+0x18/0x18
 ? raid10_sync_request+0x36c0/0x36c0 [raid10]
 ? preempt_count_sub+0xf/0xc0
 ? _raw_spin_unlock_irqrestore+0x19/0x40
 ? del_timer_sync+0xa9/0x100
 ? try_to_del_timer_sync+0xc0/0xc0
 ? _raw_spin_lock_irqsave+0x78/0xc0
 ? __lock_text_start+0x18/0x18
 ? _raw_spin_unlock_irq+0x11/0x24
 ? __list_del_entry_valid+0x68/0xa0
 ? finish_wait+0xa3/0x100
 md_thread+0x161/0x260 [md_mod]
 ? unregister_md_personality+0xa0/0xa0 [md_mod]
 ? _raw_spin_lock_irqsave+0x78/0xc0
 ? prepare_to_wait_event+0x2c0/0x2c0
 ? unregister_md_personality+0xa0/0xa0 [md_mod]
 kthread+0x148/0x180
 ? kthread_complete_and_exit+0x20/0x20
 ret_from_fork+0x1f/0x30
 </TASK>

Allocated by task 124495:
 kasan_save_stack+0x1e/0x40
 __kasan_kmalloc+0x80/0xa0
 setup_conf+0x140/0x5c0 [raid10]
 raid10_run+0x4cd/0x740 [raid10]
 md_run+0x6f9/0x1300 [md_mod]
 raid_ctr+0x2531/0x4ac0 [dm_raid]
 dm_table_add_target+0x2b0/0x620 [dm_mod]
 table_load+0x1c8/0x400 [dm_mod]
 ctl_ioctl+0x29e/0x560 [dm_mod]
 dm_compat_ctl_ioctl+0x7/0x20 [dm_mod]
 __do_compat_sys_ioctl+0xfa/0x160
 do_syscall_64+0x90/0xc0
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

Last potentially related work creation:
 kasan_save_stack+0x1e/0x40
 __kasan_record_aux_stack+0x9e/0xc0
 kvfree_call_rcu+0x84/0x480
 timerfd_release+0x82/0x140
L __fput+0xfa/0x400
 task_work_run+0x80/0xc0
 exit_to_user_mode_prepare+0x155/0x160
 syscall_exit_to_user_mode+0x12/0x40
 do_syscall_64+0x42/0xc0
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

Second to last potentially related work creation:
 kasan_save_stack+0x1e/0x40
 __kasan_record_aux_stack+0x9e/0xc0
 kvfree_call_rcu+0x84/0x480
 timerfd_release+0x82/0x140
 __fput+0xfa/0x400
 task_work_run+0x80/0xc0
 exit_to_user_mode_prepare+0x155/0x160
 syscall_exit_to_user_mode+0x12/0x40
 do_syscall_64+0x42/0xc0
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

The buggy address belongs to the object at ffff889108f3d200
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 0 bytes to the right of
 256-byte region [ffff889108f3d200, ffff889108f3d300)

The buggy address belongs to the physical page:
page:000000007ef2a34c refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1108f3c
head:000000007ef2a34c order:2 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head|zone=2)
raw: 4000000000010200 0000000000000000 dead000000000001 ffff889100042b40
raw: 0000000000000000 0000000080200020 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff889108f3d200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff889108f3d280: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff889108f3d300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                   ^
 ffff889108f3d380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff889108f3d400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Signed-off-by: NMikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: NSong Liu <song@kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Improve static type checking by using the new blk_opf_t type for
variables that represent a request flags.
Acked-by: NSong Liu <song@kernel.org>
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20220714180729.1065367-36-bvanassche@acm.orgSigned-off-by: NJens Axboe <axboe@kernel.dk>

Improve uniformity in the kernel of handling of request operation and
flags by passing these as a single argument.

Cc: Song Liu <song@kernel.org>
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20220714180729.1065367-32-bvanassche@acm.orgSigned-off-by: NJens Axboe <axboe@kernel.dk>

Replace the remaining calls of bdevname with snprintf using the %pg
format specifier.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJan Kara <jack@suse.cz>
Reviewed-by: NChaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20220713055317.1888500-10-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

Use the %pg format specifier to save on stack consumption and code size.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NSong Liu <song@kernel.org>

There is no direct mechanism to determine raid failure outside
personality. It is done by checking rdev->flags after executing
md_error(). If "faulty" flag is not set then -EBUSY is returned to
userspace. -EBUSY means that array will be failed after drive removal.

Mdadm has special routine to handle the array failure and it is executed
if -EBUSY is returned by md.

There are at least two known reasons to not consider this mechanism
as correct:
1. drive can be removed even if array will be failed[1].
2. -EBUSY seems to be wrong status. Array is not busy, but removal
   process cannot proceed safe.

-EBUSY expectation cannot be removed without breaking compatibility
with userspace. In this patch first issue is resolved by adding support
for MD_BROKEN flag for RAID1 and RAID10. Support for RAID456 is added in
next commit.

The idea is to set the MD_BROKEN if we are sure that raid is in failed
state now. This is done in each error_handler(). In md_error() MD_BROKEN
flag is checked. If is set, then -EBUSY is returned to userspace.

As in previous commit, it causes that #mdadm --set-faulty is able to
fail array. Previously proposed workaround is valid if optional
functionality[1] is disabled.

[1] commit 9a567843("md: allow last device to be forcibly removed from
    RAID1/RAID10.")
Reviewd-by: NXiao Ni <xni@redhat.com>
Signed-off-by: NMariusz Tkaczyk <mariusz.tkaczyk@linux.intel.com>
Signed-off-by: NSong Liu <song@kernel.org>

Just use a non-zero max_discard_sectors as an indicator for discard
support, similar to what is done for write zeroes.

The only places where needs special attention is the RAID5 driver,
which must clear discard support for security reasons by default,
even if the default stacking rules would allow for it.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Acked-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> [drbd]
Acked-by: Jan Höppner <hoeppner@linux.ibm.com> [s390]
Acked-by: Coly Li <colyli@suse.de> [bcache]
Acked-by: David Sterba <dsterba@suse.com> [btrfs]
Reviewed-by: NChaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220415045258.199825-25-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

Add a helper to check the nonrot flag based on the block_device instead
of having to poke into the block layer internal request_queue.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Acked-by: David Sterba <dsterba@suse.com> [btrfs]
Reviewed-by: NChaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220415045258.199825-12-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

Remove the magic autofree semantics and require the callers to explicitly
call bio_init to initialize the bio.

This allows bio_free to catch accidental bio_put calls on bio_init()ed
bios as well.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NColy Li <colyli@suse.de>
Acked-by: NMike Snitzer <snitzer@kernel.org>
Link: https://lore.kernel.org/r/20220406061228.410163-5-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

Those counters are not necessary after commit 11bb45e8aaf6 ("md: drop queue
limitation for RAID1 and RAID10"). Remove them from all code (conf and
plug structs). raid1_plug_cb and raid10_plug_cb are identical, so move
definition of raid1_plug_cb to common raid1-10 definitions and use it for
RAID10 too.
Signed-off-by: NMariusz Tkaczyk <mariusz.tkaczyk@linux.intel.com>
Signed-off-by: NSong Liu <song@kernel.org>

There are no more end-users of REQ_OP_WRITE_SAME left, so we can start
deleting it.

Link: https://lore.kernel.org/r/20220209082828.2629273-6-hch@lst.deSigned-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Pass a block_device to bio_clone_fast and __bio_clone_fast and give
the functions more suitable names.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMike Snitzer <snitzer@redhat.com>
Link: https://lore.kernel.org/r/20220202160109.108149-14-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

Pass the block_device that we plan to use this bio for and the
operation to bio_reset to optimize the assigment.  A NULL block_device
can be passed, both for the passthrough case on a raw request_queue and
to temporarily avoid refactoring some nasty code.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NChaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220124091107.642561-20-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

Pass the block_device and operation that we plan to use this bio for to
bio_alloc_bioset to optimize the assigment.  NULL/0 can be passed, both
for the passthrough case on a raw request_queue and to temporarily avoid
refactoring some nasty code.

Also move the gfp_mask argument after the nr_vecs argument for a much
more logical calling convention matching what most of the kernel does.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NChaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220124091107.642561-16-hch@lst.deSigned-off-by: NJens Axboe <axboe@kernel.dk>

This adds nowait support to the RAID10 driver. Very similar to
raid1 driver changes. It makes RAID10 driver return with EAGAIN
for situations where it could wait for eg:

  - Waiting for the barrier,
  - Reshape operation,
  - Discard operation.

wait_barrier() and regular_request_wait() fn are modified to return bool
to support error for wait barriers. They returns true in case of wait
or if wait is not required and returns false if wait was required
but not performed to support nowait.
Reviewed-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NVishal Verma <vverma@digitalocean.com>
Signed-off-by: NSong Liu <song@kernel.org>

As suggested by Neil Brown[1], this limitation seems to be
deprecated.

With plugging in use, writes are processed behind the raid thread
and conf->pending_count is not increased. This limitation occurs only
if caller doesn't use plugs.

It can be avoided and often it is (with plugging). There are no reports
that queue is growing to enormous size so remove queue limitation for
non-plugged IOs too.

[1] https://lore.kernel.org/linux-raid/162496301481.7211.18031090130574610495@noble.neil.brown.nameSigned-off-by: NMariusz Tkaczyk <mariusz.tkaczyk@linux.intel.com>
Signed-off-by: NSong Liu <song@kernel.org>

Actually, mddev is not used by md_new_event.
Signed-off-by: NGuoqing Jiang <guoqing.jiang@linux.dev>
Signed-off-by: NSong Liu <songliubraving@fb.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

We are seeing the following warning in raid10_handle_discard.
[  695.110751] =============================
[  695.131439] WARNING: suspicious RCU usage
[  695.151389] 4.18.0-319.el8.x86_64+debug #1 Not tainted
[  695.174413] -----------------------------
[  695.192603] drivers/md/raid10.c:1776 suspicious
rcu_dereference_check() usage!
[  695.225107] other info that might help us debug this:
[  695.260940] rcu_scheduler_active = 2, debug_locks = 1
[  695.290157] no locks held by mkfs.xfs/10186.

In the first loop of function raid10_handle_discard. It already
determines which disk need to handle discard request and add the
rdev reference count rdev->nr_pending. So the conf->mirrors will
not change until all bios come back from underlayer disks. It
doesn't need to use rcu_dereference to get rdev.

Cc: stable@vger.kernel.org
Fixes: d30588b2 ('md/raid10: improve raid10 discard request')
Signed-off-by: NXiao Ni <xni@redhat.com>
Acked-by: NGuoqing Jiang <guoqing.jiang@linux.dev>
Signed-off-by: NSong Liu <songliubraving@fb.com>

Similar to [1], this patch fixes the same bug in raid10. Also cleanup the
comments.

[1] commit 2417b986 ("md/raid1: properly indicate failure when ending
                         a failed write request")
Cc: stable@vger.kernel.org
Fixes: 7cee6d4e ("md/raid10: end bio when the device faulty")
Signed-off-by: NWei Shuyu <wsy@dogben.com>
Acked-by: NGuoqing Jiang <jiangguoqing@kylinos.cn>
Signed-off-by: NSong Liu <song@kernel.org>

For raid10, we record the start time between split bio and clone bio,
and finish the accounting in the final endio.

Also introduce start_time in r10bio accordingly.
Signed-off-by: NGuoqing Jiang <jiangguoqing@kylinos.cn>
Signed-off-by: NSong Liu <song@kernel.org>

For far layout, the discard region is not continuous on disks. So it needs
far copies r10bio to cover all regions. It needs a way to know all r10bios
have finish or not. Similar with raid10_sync_request, only the first r10bio
master_bio records the discard bio. Other r10bios master_bio record the
first r10bio. The first r10bio can finish after other r10bios finish and
then return the discard bio.
Tested-by: NAdrian Huang <ahuang12@lenovo.com>
Signed-off-by: NXiao Ni <xni@redhat.com>
Signed-off-by: NSong Liu <songliubraving@fb.com>

Now the discard request is split by chunk size. So it takes a long time
to finish mkfs on disks which support discard function. This patch improve
handling raid10 discard request. It uses the similar way with patch
29efc390 (md/md0: optimize raid0 discard handling).

But it's a little complex than raid0. Because raid10 has different layout.
If raid10 is offset layout and the discard request is smaller than stripe
size. There are some holes when we submit discard bio to underlayer disks.

For example: five disks (disk1 - disk5)
D01 D02 D03 D04 D05
D05 D01 D02 D03 D04
D06 D07 D08 D09 D10
D10 D06 D07 D08 D09
The discard bio just wants to discard from D03 to D10. For disk3, there is
a hole between D03 and D08. For disk4, there is a hole between D04 and D09.
D03 is a chunk, raid10_write_request can handle one chunk perfectly. So
the part that is not aligned with stripe size is still handled by
raid10_write_request.

If reshape is running when discard bio comes and the discard bio spans the
reshape position, raid10_write_request is responsible to handle this
discard bio.

I did a test with this patch set.
Without patch:
time mkfs.xfs /dev/md0
real4m39.775s
user0m0.000s
sys0m0.298s

With patch:
time mkfs.xfs /dev/md0
real0m0.105s
user0m0.000s
sys0m0.007s

nvme3n1           259:1    0   477G  0 disk
└─nvme3n1p1       259:10   0    50G  0 part
nvme4n1           259:2    0   477G  0 disk
└─nvme4n1p1       259:11   0    50G  0 part
nvme5n1           259:6    0   477G  0 disk
└─nvme5n1p1       259:12   0    50G  0 part
nvme2n1           259:9    0   477G  0 disk
└─nvme2n1p1       259:15   0    50G  0 part
nvme0n1           259:13   0   477G  0 disk
└─nvme0n1p1       259:14   0    50G  0 part
Reviewed-by: NColy Li <colyli@suse.de>
Reviewed-by: NGuoqing Jiang <guoqing.jiang@cloud.ionos.com>
Tested-by: NAdrian Huang <ahuang12@lenovo.com>
Signed-off-by: NXiao Ni <xni@redhat.com>
Signed-off-by: NSong Liu <songliubraving@fb.com>

The following patch will reuse these logics, so pull the same codes into
one function.
Tested-by: NAdrian Huang <ahuang12@lenovo.com>
Signed-off-by: NXiao Ni <xni@redhat.com>
Signed-off-by: NSong Liu <songliubraving@fb.com>

Now it allocs r10bio->devs[conf->copies]. Discard bio needs to submit
to all member disks and it needs to use r10bio. So extend to
r10bio->devs[geo.raid_disks].
Reviewed-by: NColy Li <colyli@suse.de>
Tested-by: NAdrian Huang <ahuang12@lenovo.com>
Signed-off-by: NXiao Ni <xni@redhat.com>
Signed-off-by: NSong Liu <songliubraving@fb.com>

A bio allocated by bio_alloc_bioset comes pre-zeroed, no need to
clear random fields.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NSong Liu <song@kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

bio_alloc_mddev is never called with a NULL mddev, and ->bio_set is
initialized in md_run, so it always must be initialized as well.  Just
open code the remaining call to bio_alloc_bioset.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NSong Liu <song@kernel.org>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Acked-by: NDamien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

Replace the gendisk pointer in struct bio with a pointer to the newly
improved struct block device.  From that the gendisk can be trivially
accessed with an extra indirection, but it also allows to directly
look up all information related to partition remapping.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

This reverts commit 8650a889.

Matthew Ruffell reported data corruption in raid10 due to the changes
in discard handling [1]. Revert these changes before we find a proper fix.

[1] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1907262/
Cc: Matthew Ruffell <matthew.ruffell@canonical.com>
Cc: Xiao Ni <xni@redhat.com>
Signed-off-by: NSong Liu <songliubraving@fb.com>

This reverts commit f046f5d0.

Matthew Ruffell reported data corruption in raid10 due to the changes
in discard handling [1]. Revert these changes before we find a proper fix.

[1] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1907262/
Cc: Matthew Ruffell <matthew.ruffell@canonical.com>
Cc: Xiao Ni <xni@redhat.com>
Signed-off-by: NSong Liu <songliubraving@fb.com>

This reverts commit bcc90d28.

Matthew Ruffell reported data corruption in raid10 due to the changes
in discard handling [1]. Revert these changes before we find a proper fix.

[1] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1907262/
Cc: Matthew Ruffell <matthew.ruffell@canonical.com>
Cc: Xiao Ni <xni@redhat.com>
Signed-off-by: NSong Liu <songliubraving@fb.com>

This reverts commit d3ee2d84.

Matthew Ruffell reported data corruption in raid10 due to the changes
in discard handling [1]. Revert these changes before we find a proper fix.

[1] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1907262/
Cc: Matthew Ruffell <matthew.ruffell@canonical.com>
Cc: Xiao Ni <xni@redhat.com>
Signed-off-by: NSong Liu <songliubraving@fb.com>

The request_queue can trivially be derived from the bio.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NDamien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NChaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>