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7 weeks agoublk: add UBLK_U_CMD_REG_BUF/UNREG_BUF control commands
Ming Lei [Tue, 31 Mar 2026 15:31:52 +0000 (23:31 +0800)] 
ublk: add UBLK_U_CMD_REG_BUF/UNREG_BUF control commands

Add control commands for registering and unregistering shared memory
buffers for zero-copy I/O:

- UBLK_U_CMD_REG_BUF (0x18): pins pages from userspace, inserts PFN
  ranges into a per-device maple tree for O(log n) lookup during I/O.
  Buffer pointers are tracked in a per-device xarray. Returns the
  assigned buffer index.

- UBLK_U_CMD_UNREG_BUF (0x19): removes PFN entries and unpins pages.

Queue freeze/unfreeze is handled internally so userspace need not
quiesce the device during registration.

Also adds:
- UBLK_IO_F_SHMEM_ZC flag and addr encoding helpers in UAPI header
  (16-bit buffer index supporting up to 65536 buffers)
- Data structures (ublk_buf, ublk_buf_range) and xarray/maple tree
- __ublk_ctrl_reg_buf() helper for PFN insertion with error unwinding
- __ublk_ctrl_unreg_buf() helper for cleanup reuse
- ublk_support_shmem_zc() / ublk_dev_support_shmem_zc() stubs
  (returning false — feature not enabled yet)

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://patch.msgid.link/20260331153207.3635125-2-ming.lei@redhat.com
[axboe: fixup ublk_buf_reg -> ublk_shmem_buf_reg errors, comments]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 weeks agodrbd: use get_random_u64() where appropriate
David Carlier [Sun, 5 Apr 2026 15:47:04 +0000 (16:47 +0100)] 
drbd: use get_random_u64() where appropriate

Use the typed random integer helpers instead of
get_random_bytes() when filling a single integer variable.
The helpers return the value directly, require no pointer
or size argument, and better express intent.

Signed-off-by: David Carlier <devnexen@gmail.com>
Reviewed-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com>
Link: https://patch.msgid.link/20260405154704.4610-1-devnexen@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 weeks agodrbd: remove DRBD_GENLA_F_MANDATORY flag handling
Christoph Böhmwalder [Fri, 3 Apr 2026 13:29:53 +0000 (15:29 +0200)] 
drbd: remove DRBD_GENLA_F_MANDATORY flag handling

DRBD used a custom mechanism to mark netlink attributes as "mandatory":
bit 14 of nla_type was repurposed as DRBD_GENLA_F_MANDATORY. Attributes
sent from userspace that had this bit present and that were unknown
to the kernel would lead to an error.

Since commit ef6243acb478 ("genetlink: optionally validate strictly/dumps"),
the generic netlink layer rejects unknown top-level attributes when
strict validation is enabled. DRBD never opted out of strict
validation, so unknown top-level attributes are already rejected by
the netlink core.

The mandatory flag mechanism was required for nested attributes, because
these are parsed liberally, silently dropping attributes unknown to the
kernel.

This prepares for the move to a new YNL-based family, which will use the
now-default strict parsing.
The current family is not expected to gain any new attributes, which
makes this change safe.

Old userspace that still sets bit 14 is unaffected: nla_type()
strips it before __nla_validate_parse() performs attribute validation,
so the bit never reaches DRBD.

Remove all references to the mandatory flag in DRBD.

Cc: Johannes Berg <johannes.berg@intel.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com>
Link: https://patch.msgid.link/20260403132953.2248751-1-christoph.boehmwalder@linbit.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 weeks agoblk-wbt: remove WARN_ON_ONCE from wbt_init_enable_default()
Yuto Ohnuki [Mon, 16 Mar 2026 07:03:59 +0000 (07:03 +0000)] 
blk-wbt: remove WARN_ON_ONCE from wbt_init_enable_default()

wbt_init_enable_default() uses WARN_ON_ONCE to check for failures from
wbt_alloc() and wbt_init(). However, both are expected failure paths:

- wbt_alloc() can return NULL under memory pressure (-ENOMEM)
- wbt_init() can fail with -EBUSY if wbt is already registered

syzbot triggers this by injecting memory allocation failures during MTD
partition creation via ioctl(BLKPG), causing a spurious warning.

wbt_init_enable_default() is a best-effort initialization called from
blk_register_queue() with a void return type. Failure simply means the
disk operates without writeback throttling, which is harmless.

Replace WARN_ON_ONCE with plain if-checks, consistent with how
wbt_set_lat() in the same file already handles these failures. Add a
pr_warn() for the wbt_init() failure to retain diagnostic information
without triggering a full stack trace.

Reported-by: syzbot+71fcf20f7c1e5043d78c@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=71fcf20f7c1e5043d78c
Fixes: 41afaeeda509 ("blk-wbt: fix possible deadlock to nest pcpu_alloc_mutex under q_usage_counter")
Signed-off-by: Yuto Ohnuki <ytohnuki@amazon.com>
Reviewed-by: Yu Kuai <yukuai@fnnas.com>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Link: https://patch.msgid.link/20260316070358.65225-2-ytohnuki@amazon.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 weeks agoselftests: ublk: test that teardown after incomplete recovery completes
Uday Shankar [Mon, 6 Apr 2026 04:25:31 +0000 (22:25 -0600)] 
selftests: ublk: test that teardown after incomplete recovery completes

Before the fix, teardown of a ublk server that was attempting to recover
a device, but died when it had submitted a nonempty proper subset of the
fetch commands to any queue would loop forever. Add a test to verify
that, after the fix, teardown completes. This is done by:

- Adding a new argument to the fault_inject target that causes it die
  after fetching a nonempty proper subset of the IOs to a queue
- Using that argument in a new test while trying to recover an
  already-created device
- Attempting to delete the ublk device at the end of the test; this
  hangs forever if teardown from the fault-injected ublk server never
  completed.

It was manually verified that the test passes with the fix and hangs
without it.

Signed-off-by: Uday Shankar <ushankar@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://patch.msgid.link/20260405-cancel-v2-2-02d711e643c2@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 weeks agoublk: reset per-IO canceled flag on each fetch
Uday Shankar [Mon, 6 Apr 2026 04:25:30 +0000 (22:25 -0600)] 
ublk: reset per-IO canceled flag on each fetch

If a ublk server starts recovering devices but dies before issuing fetch
commands for all IOs, cancellation of the fetch commands that were
successfully issued may never complete. This is because the per-IO
canceled flag can remain set even after the fetch for that IO has been
submitted - the per-IO canceled flags for all IOs in a queue are reset
together only once all IOs for that queue have been fetched. So if a
nonempty proper subset of the IOs for a queue are fetched when the ublk
server dies, the IOs in that subset will never successfully be canceled,
as their canceled flags remain set, and this prevents ublk_cancel_cmd
from actually calling io_uring_cmd_done on the commands, despite the
fact that they are outstanding.

Fix this by resetting the per-IO cancel flags immediately when each IO
is fetched instead of waiting for all IOs for the queue (which may never
happen).

Signed-off-by: Uday Shankar <ushankar@purestorage.com>
Fixes: 728cbac5fe21 ("ublk: move device reset into ublk_ch_release()")
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: zhang, the-essence-of-life <zhangweize9@gmail.com>
Link: https://patch.msgid.link/20260405-cancel-v2-1-02d711e643c2@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 weeks agoblock: remove unused BVEC_ITER_ALL_INIT
Caleb Sander Mateos [Fri, 3 Apr 2026 18:48:51 +0000 (12:48 -0600)] 
block: remove unused BVEC_ITER_ALL_INIT

This macro no longer has any users, so remove it.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Link: https://patch.msgid.link/20260403184852.2140919-1-csander@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 weeks agobcache: fix uninitialized closure object
Mingzhe Zou [Fri, 3 Apr 2026 04:21:35 +0000 (12:21 +0800)] 
bcache: fix uninitialized closure object

In the previous patch ("bcache: fix cached_dev.sb_bio use-after-free and
crash"), we adopted a simple modification suggestion from AI to fix the
use-after-free.

But in actual testing, we found an extreme case where the device is
stopped before calling bch_write_bdev_super().

At this point, struct closure sb_write has not been initialized yet.
For this patch, we ensure that sb_bio has been completed via
sb_write_mutex.

Signed-off-by: Mingzhe Zou <mingzhe.zou@easystack.cn>
Signed-off-by: Coly Li <colyli@fnnas.com>
Link: https://patch.msgid.link/20260403042135.2221247-1-colyli@fnnas.com
Fixes: fec114a98b87 ("bcache: fix cached_dev.sb_bio use-after-free and crash")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 weeks agobcache: fix cached_dev.sb_bio use-after-free and crash
Mingzhe Zou [Sun, 22 Mar 2026 13:41:02 +0000 (21:41 +0800)] 
bcache: fix cached_dev.sb_bio use-after-free and crash

In our production environment, we have received multiple crash reports
regarding libceph, which have caught our attention:

```
[6888366.280350] Call Trace:
[6888366.280452]  blk_update_request+0x14e/0x370
[6888366.280561]  blk_mq_end_request+0x1a/0x130
[6888366.280671]  rbd_img_handle_request+0x1a0/0x1b0 [rbd]
[6888366.280792]  rbd_obj_handle_request+0x32/0x40 [rbd]
[6888366.280903]  __complete_request+0x22/0x70 [libceph]
[6888366.281032]  osd_dispatch+0x15e/0xb40 [libceph]
[6888366.281164]  ? inet_recvmsg+0x5b/0xd0
[6888366.281272]  ? ceph_tcp_recvmsg+0x6f/0xa0 [libceph]
[6888366.281405]  ceph_con_process_message+0x79/0x140 [libceph]
[6888366.281534]  ceph_con_v1_try_read+0x5d7/0xf30 [libceph]
[6888366.281661]  ceph_con_workfn+0x329/0x680 [libceph]
```

After analyzing the coredump file, we found that the address of
dc->sb_bio has been freed. We know that cached_dev is only freed when it
is stopped.

Since sb_bio is a part of struct cached_dev, rather than an alloc every
time.  If the device is stopped while writing to the superblock, the
released address will be accessed at endio.

This patch hopes to wait for sb_write to complete in cached_dev_free.

It should be noted that we analyzed the cause of the problem, then tell
all details to the QWEN and adopted the modifications it made.

Signed-off-by: Mingzhe Zou <mingzhe.zou@easystack.cn>
Fixes: cafe563591446 ("bcache: A block layer cache")
Cc: stable@vger.kernel.org # 3.10+
Signed-off-by: Coly Li <colyli@fnnas.com>
Link: https://patch.msgid.link/20260322134102.480107-1-colyli@fnnas.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
7 weeks agoblock: use sysfs_emit in sysfs show functions
Thorsten Blum [Thu, 2 Apr 2026 16:50:00 +0000 (18:50 +0200)] 
block: use sysfs_emit in sysfs show functions

Replace sprintf() with sysfs_emit() in sysfs show functions.
sysfs_emit() is preferred for formatting sysfs output because it
provides safer bounds checking.

Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://patch.msgid.link/20260402164958.894879-4-thorsten.blum@linux.dev
Signed-off-by: Jens Axboe <axboe@kernel.dk>
8 weeks agoblk-crypto: fix name of the bio completion callback
Christoph Hellwig [Wed, 1 Apr 2026 13:58:51 +0000 (15:58 +0200)] 
blk-crypto: fix name of the bio completion callback

Fix a simple naming issue in the documentation: the completion
routine is called bi_end_io and not bi_complete.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Eric Biggers <ebiggers@kernel.org>
Link: https://patch.msgid.link/20260401135854.125109-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
8 weeks agobio: fix kmemleak false positives from percpu bio alloc cache
Ming Lei [Thu, 26 Mar 2026 14:40:58 +0000 (22:40 +0800)] 
bio: fix kmemleak false positives from percpu bio alloc cache

When a bio is allocated from the mempool with REQ_ALLOC_CACHE set and
later completed, bio_put() places it into the per-cpu bio_alloc_cache
via bio_put_percpu_cache() instead of freeing it back to the
mempool/slab. The slab allocation remains tracked by kmemleak, but the
only reference to the bio is through the percpu cache's free_list,
which kmemleak fails to trace through percpu memory. This causes
kmemleak to report the cached bios as unreferenced objects.

Use symmetric kmemleak_free()/kmemleak_alloc() calls to properly track
bios across percpu cache transitions:

 - bio_put_percpu_cache: call kmemleak_free() when a bio enters the
   cache, unregistering it from kmemleak tracking.

 - bio_alloc_percpu_cache: call kmemleak_alloc() when a bio is taken
   from the cache for reuse, re-registering it so that genuine leaks
   of reused bios remain detectable.

 - __bio_alloc_cache_prune: call kmemleak_alloc() before bio_free() so
   that kmem_cache_free()'s internal kmemleak_free() has a matching
   allocation to pair with.

Tested-by: Yi Zhang <yi.zhang@redhat.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://patch.msgid.link/20260326144058.2392319-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
8 weeks agoblk-iocost: fix busy_level reset when no IOs complete
Jialin Wang [Tue, 31 Mar 2026 10:05:09 +0000 (10:05 +0000)] 
blk-iocost: fix busy_level reset when no IOs complete

When a disk is saturated, it is common for no IOs to complete within a
timer period. Currently, in this case, rq_wait_pct and missed_ppm are
calculated as 0, the iocost incorrectly interprets this as meeting QoS
targets and resets busy_level to 0.

This reset prevents busy_level from reaching the threshold (4) needed
to reduce vrate. On certain cloud storage, such as Azure Premium SSD,
we observed that iocost may fail to reduce vrate for tens of seconds
during saturation, failing to mitigate noisy neighbor issues.

Fix this by tracking the number of IO completions (nr_done) in a period.
If nr_done is 0 and there are lagging IOs, the saturation status is
unknown, so we keep busy_level unchanged.

The issue is consistently reproducible on Azure Standard_D8as_v5 (Dasv5)
VMs with 512GB Premium SSD (P20) using the script below. It was not
observed on GCP n2d VMs (with 100G pd-ssd and 1.5T local-ssd), and no
regressions were found with this patch. In this script, cgA performs
large IOs with iodepth=128, while cgB performs small IOs with iodepth=1
rate_iops=100 rw=randrw. With iocost enabled, we expect it to throttle
cgA, the submission latency (slat) of cgA should be significantly higher,
cgB can reach 200 IOPS and the completion latency (clat) should below.

  BLK_DEVID="8:0"
  MODEL="rbps=173471131 rseqiops=3566 rrandiops=3566 wbps=173333269 wseqiops=3566 wrandiops=3566"
  QOS="rpct=90 rlat=3500 wpct=90 wlat=3500 min=80 max=10000"

  echo "$BLK_DEVID ctrl=user model=linear $MODEL" > /sys/fs/cgroup/io.cost.model
  echo "$BLK_DEVID enable=1 ctrl=user $QOS" > /sys/fs/cgroup/io.cost.qos

  CG_A="/sys/fs/cgroup/cgA"
  CG_B="/sys/fs/cgroup/cgB"

  FILE_A="/path/to/sda/A.fio.testfile"
  FILE_B="/path/to/sda/B.fio.testfile"
  RESULT_DIR="./iocost_results_$(date +%Y%m%d_%H%M%S)"

  mkdir -p "$CG_A" "$CG_B" "$RESULT_DIR"

  get_result() {
    local file=$1
    local label=$2

    local results=$(jq -r '
    .jobs[0].mixed |
    ( .iops | tonumber | round ) as $iops |
    ( .bw_bytes / 1024 / 1024 ) as $bps |
    ( .slat_ns.mean / 1000000 ) as $slat |
    ( .clat_ns.mean / 1000000 ) as $avg |
    ( .clat_ns.max / 1000000 ) as $max |
    ( .clat_ns.percentile["90.000000"] / 1000000 ) as $p90 |
    ( .clat_ns.percentile["99.000000"] / 1000000 ) as $p99 |
    ( .clat_ns.percentile["99.900000"] / 1000000 ) as $p999 |
    ( .clat_ns.percentile["99.990000"] / 1000000 ) as $p9999 |
    "\($iops)|\($bps)|\($slat)|\($avg)|\($max)|\($p90)|\($p99)|\($p999)|\($p9999)"
    ' "$file")

    IFS='|' read -r iops bps slat avg max p90 p99 p999 p9999 <<<"$results"
    printf "%-8s %-6s %-7.2f %-8.2f %-8.2f %-8.2f %-8.2f %-8.2f %-8.2f %-8.2f\n" \
           "$label" "$iops" "$bps" "$slat" "$avg" "$max" "$p90" "$p99" "$p999" "$p9999"
  }

  run_fio() {
    local cg_path=$1
    local filename=$2
    local name=$3
    local bs=$4
    local qd=$5
    local out=$6
    shift 6
    local extra=$@

    (
      pid=$(sh -c 'echo $PPID')
      echo $pid >"${cg_path}/cgroup.procs"
      fio --name="$name" --filename="$filename" --direct=1 --rw=randrw --rwmixread=50 \
          --ioengine=libaio --bs="$bs" --iodepth="$qd" --size=4G --runtime=10 \
          --time_based --group_reporting --unified_rw_reporting=mixed \
          --output-format=json --output="$out" $extra >/dev/null 2>&1
    ) &
  }

  echo "Starting Test ..."

  for bs_b in "4k" "32k" "256k"; do
    echo "Running iteration: BS=$bs_b"
    out_a="${RESULT_DIR}/cgA_1m.json"
    out_b="${RESULT_DIR}/cgB_${bs_b}.json"

    # cgA: Heavy background (BS 1MB, QD 128)
    run_fio "$CG_A" "$FILE_A" "cgA" "1m" 128 "$out_a"
    # cgB: Latency sensitive (Variable BS, QD 1, Read/Write IOPS limit 100)
    run_fio "$CG_B" "$FILE_B" "cgB" "$bs_b" 1 "$out_b" "--rate_iops=100"

    wait
    SUMMARY_DATA+="$(get_result "$out_a" "cgA-1m")"$'\n'
    SUMMARY_DATA+="$(get_result "$out_b" "cgB-$bs_b")"$'\n\n'
  done

  echo -e "\nFinal Results Summary:\n"

  printf "%-8s %-6s %-7s %-8s %-8s %-8s %-8s %-8s %-8s %-8s\n" \
          "" "" "" "slat" "clat" "clat" "clat" "clat" "clat" "clat"
  printf "%-8s %-6s %-7s %-8s %-8s %-8s %-8s %-8s %-8s %-8s\n\n" \
          "CGROUP" "IOPS" "MB/s" "avg(ms)" "avg(ms)" "max(ms)" "P90(ms)" "P99" "P99.9" "P99.99"
  echo "$SUMMARY_DATA"

  echo "Results saved in $RESULT_DIR"

Before:
                          slat     clat     clat     clat     clat     clat     clat
  CGROUP   IOPS   MB/s    avg(ms)  avg(ms)  max(ms)  P90(ms)  P99      P99.9    P99.99

  cgA-1m   166    166.37  3.44     748.95   1298.29  977.27   1233.13  1300.23  1300.23
  cgB-4k   5      0.02    0.02     181.74   761.32   742.39   759.17   759.17   759.17

  cgA-1m   167    166.51  1.98     748.68   1549.41  809.50   1451.23  1551.89  1551.89
  cgB-32k  6      0.18    0.02     169.98   761.76   742.39   759.17   759.17   759.17

  cgA-1m   166    165.55  2.89     750.89   1540.37  851.44   1451.23  1535.12  1535.12
  cgB-256k 5      1.30    0.02     191.35   759.51   750.78   759.17   759.17   759.17

After:
                          slat     clat     clat     clat     clat     clat     clat
  CGROUP   IOPS   MB/s    avg(ms)  avg(ms)  max(ms)  P90(ms)  P99      P99.9    P99.99

  cgA-1m   162    162.48  6.14     749.69   850.02   826.28   834.67   843.06   851.44
  cgB-4k   199    0.78    0.01     1.95     42.12    2.57     7.50     34.87    42.21

  cgA-1m   146    146.20  6.83     833.04   908.68   893.39   901.78   910.16   910.16
  cgB-32k  200    6.25    0.01     2.32     31.40    3.06     7.50     16.58    31.33

  cgA-1m   110    110.46  9.04     1082.67  1197.91  1182.79  1199.57  1199.57  1199.57
  cgB-256k 200    49.98   0.02     3.69     22.20    4.88     9.11     20.05    22.15

Signed-off-by: Jialin Wang <wjl.linux@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://patch.msgid.link/20260331100509.182882-1-wjl.linux@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
8 weeks agoblk-cgroup: fix disk reference leak in blkcg_maybe_throttle_current()
Jackie Liu [Tue, 31 Mar 2026 08:50:54 +0000 (16:50 +0800)] 
blk-cgroup: fix disk reference leak in blkcg_maybe_throttle_current()

Add the missing put_disk() on the error path in
blkcg_maybe_throttle_current(). When blkcg lookup, blkg lookup, or
blkg_tryget() fails, the function jumps to the out label which only
calls rcu_read_unlock() but does not release the disk reference acquired
by blkcg_schedule_throttle() via get_device(). Since current->throttle_disk
is already set to NULL before the lookup, blkcg_exit() cannot release
this reference either, causing the disk to never be freed.

Restore the reference release that was present as blk_put_queue() in the
original code but was inadvertently dropped during the conversion from
request_queue to gendisk.

Fixes: f05837ed73d0 ("blk-cgroup: store a gendisk to throttle in struct task_struct")
Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/20260331085054.46857-1-liu.yun@linux.dev
Signed-off-by: Jens Axboe <axboe@kernel.dk>
8 weeks agozloop: add max_open_zones option
Damien Le Moal [Thu, 26 Mar 2026 20:32:45 +0000 (05:32 +0900)] 
zloop: add max_open_zones option

Introduce the new max_open_zones option to allow specifying a limit on
the maximum number of open zones of a zloop device. This change allows
creating a zloop device that can more closely mimick the characteristics
of a physical SMR drive.

When set to a non zero value, only up to max_open_zones zones can be in
the implicit open (BLK_ZONE_COND_IMP_OPEN) and explicit open
(BLK_ZONE_COND_EXP_OPEN) conditions at any time. The transition to the
implicit open condition of a zone on a write operation can result in an
implicit close of an already implicitly open zone. This is handled in
the function zloop_do_open_zone(). This function also handles
transitions to the explicit open condition. Implicit close transitions
are handled using an LRU ordered list of open zones which is managed
using the helper functions zloop_lru_rotate_open_zone() and
zloop_lru_remove_open_zone().

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/20260326203245.946830-1-dlemoal@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
8 weeks agoblock: fix zones_cond memory leak on zone revalidation error paths
Jackie Liu [Tue, 31 Mar 2026 11:12:16 +0000 (19:12 +0800)] 
block: fix zones_cond memory leak on zone revalidation error paths

When blk_revalidate_disk_zones() fails after disk_revalidate_zone_resources()
has allocated args.zones_cond, the memory is leaked because no error path
frees it.

Fixes: 6e945ffb6555 ("block: use zone condition to determine conventional zones")
Suggested-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
Link: https://patch.msgid.link/20260331111216.24242-1-liu.yun@linux.dev
Signed-off-by: Jens Axboe <axboe@kernel.dk>
8 weeks agoloop: fix partition scan race between udev and loop_reread_partitions()
Daan De Meyer [Tue, 31 Mar 2026 10:51:28 +0000 (10:51 +0000)] 
loop: fix partition scan race between udev and loop_reread_partitions()

When LOOP_CONFIGURE is called with LO_FLAGS_PARTSCAN, the following
sequence occurs:

  1. disk_force_media_change() sets GD_NEED_PART_SCAN
  2. Uevent suppression is lifted and a KOBJ_CHANGE uevent is sent
  3. loop_global_unlock() releases the lock
  4. loop_reread_partitions() calls bdev_disk_changed() to scan

There is a race between steps 2 and 4: when udev receives the uevent
and opens the device before loop_reread_partitions() runs,
blkdev_get_whole() in bdev.c sees GD_NEED_PART_SCAN set and calls
bdev_disk_changed() for a first scan. Then loop_reread_partitions()
does a second scan. The open_mutex serializes these two scans, but
does not prevent both from running.

The second scan in bdev_disk_changed() drops all partition devices
from the first scan (via blk_drop_partitions()) before re-adding
them, causing partition block devices to briefly disappear. This
breaks any systemd unit with BindsTo= on the partition device: systemd
observes the device going dead, fails the dependent units, and does
not retry them when the device reappears.

Fix this by removing the GD_NEED_PART_SCAN set from
disk_force_media_change() entirely. None of the current callers need
the lazy on-open partition scan triggered by this flag:

  - floppy: sets GENHD_FL_NO_PART, so disk_has_partscan() is always
    false and GD_NEED_PART_SCAN has no effect.
  - loop (loop_configure, loop_change_fd): when LO_FLAGS_PARTSCAN is
    set, loop_reread_partitions() performs an explicit scan. When not
    set, GD_SUPPRESS_PART_SCAN prevents the lazy scan path.
  - loop (__loop_clr_fd): calls bdev_disk_changed() explicitly if
    LO_FLAGS_PARTSCAN is set.
  - nbd (nbd_clear_sock_ioctl): capacity is set to zero immediately
    after; nbd manages GD_NEED_PART_SCAN explicitly elsewhere.

With GD_NEED_PART_SCAN no longer set by disk_force_media_change(),
udev opening the loop device after the uevent no longer triggers a
redundant scan in blkdev_get_whole(), and only the single explicit
scan from loop_reread_partitions() runs.

A regression test for this bug has been submitted to blktests:
https://github.com/linux-blktests/blktests/pull/240.

Fixes: 9f65c489b68d ("loop: raise media_change event")
Signed-off-by: Daan De Meyer <daan@amutable.com>
Acked-by: Christian Brauner <brauner@kernel.org>
Link: https://patch.msgid.link/20260331105130.1077599-1-daan@amutable.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
8 weeks agosed-opal: Add STACK_RESET command
Milan Broz [Tue, 10 Mar 2026 09:53:49 +0000 (10:53 +0100)] 
sed-opal: Add STACK_RESET command

The TCG Opal device could enter a state where no new session can be
created, blocking even Discovery or PSID reset. While a power cycle
or waiting for the timeout should work, there is another possibility
for recovery: using the Stack Reset command.

The Stack Reset command is defined in the TCG Storage Architecture Core
Specification and is mandatory for all Opal devices (see Section 3.3.6
of the Opal SSC specification).

This patch implements the Stack Reset command. Sending it should clear
all active sessions immediately, allowing subsequent commands to run
successfully. While it is a TCG transport layer command, the Linux
kernel implements only Opal ioctls, so it makes sense to use the
IOC_OPAL ioctl interface.

The Stack Reset takes no arguments; the response can be success or pending.
If the command reports a pending state, userspace can try to repeat it;
in this case, the code returns -EBUSY.

Signed-off-by: Milan Broz <gmazyland@gmail.com>
Reviewed-by: Ondrej Kozina <okozina@redhat.com>
Link: https://patch.msgid.link/20260310095349.411287-1-gmazyland@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2 months agoMerge tag 'nvme-7.1-2026-03-27' of git://git.infradead.org/nvme into for-7.1/block
Jens Axboe [Fri, 27 Mar 2026 15:51:17 +0000 (09:51 -0600)] 
Merge tag 'nvme-7.1-2026-03-27' of git://git.infradead.org/nvme into for-7.1/block

Pull NVMe updates from Keith:

"- Fabrics authentication updates (Eric, Alistar)
 - Enanced block queue limits support (Caleb)
 - Workqueue usage updates (Marco)
 - A new write zeroes device quirk (Robert)
 - Tagset cleanup fix for loop device (Nilay)"

* tag 'nvme-7.1-2026-03-27' of git://git.infradead.org/nvme: (41 commits)
  nvme-loop: do not cancel I/O and admin tagset during ctrl reset/shutdown
  nvme: add WQ_PERCPU to alloc_workqueue users
  nvmet-fc: add WQ_PERCPU to alloc_workqueue users
  nvmet: replace use of system_wq with system_percpu_wq
  nvme-auth: Don't propose NVME_AUTH_DHGROUP_NULL with SC_C
  nvme: Add the DHCHAP maximum HD IDs
  nvme-pci: add NVME_QUIRK_DISABLE_WRITE_ZEROES for Kingston OM3SGP4
  nvme: respect NVME_QUIRK_DISABLE_WRITE_ZEROES when wzsl is set
  nvmet: report NPDGL and NPDAL
  nvmet: use NVME_NS_FEAT_OPTPERF_SHIFT
  nvme: set discard_granularity from NPDG/NPDA
  nvme: add from0based() helper
  nvme: always issue I/O Command Set specific Identify Namespace
  nvme: update nvme_id_ns OPTPERF constants
  nvme: fold nvme_config_discard() into nvme_update_disk_info()
  nvme: add preferred I/O size fields to struct nvme_id_ns_nvm
  nvme: Allow reauth from sysfs
  nvme: Expose the tls_configured sysfs for secure concat connections
  nvmet-tcp: Don't free SQ on authentication success
  nvmet-tcp: Don't error if TLS is enabed on a reset
  ...

2 months agonvme-loop: do not cancel I/O and admin tagset during ctrl reset/shutdown
Nilay Shroff [Fri, 13 Mar 2026 11:38:48 +0000 (17:08 +0530)] 
nvme-loop: do not cancel I/O and admin tagset during ctrl reset/shutdown

Cancelling the I/O and admin tagsets during nvme-loop controller reset
or shutdown is unnecessary. The subsequent destruction of the I/O and
admin queues already waits for all in-flight target operations to
complete.

Cancelling the tagsets first also opens a race window. After a request
tag has been cancelled, a late completion from the target may still
arrive before the queues are destroyed. In that case the completion path
may access a request whose tag has already been cancelled or freed,
which can lead to a kernel crash. Please see below the kernel crash
encountered while running blktests nvme/040:

run blktests nvme/040 at 2026-03-08 06:34:27
loop0: detected capacity change from 0 to 2097152
nvmet: adding nsid 1 to subsystem blktests-subsystem-1
nvmet: Created nvm controller 1 for subsystem blktests-subsystem-1 for NQN nqn.2014-08.org.nvmexpress:uuid:0f01fb42-9f7f-4856-b0b3-51e60b8de349.
nvme nvme6: creating 96 I/O queues.
nvme nvme6: new ctrl: "blktests-subsystem-1"
nvme_log_error: 1 callbacks suppressed
block nvme6n1: no usable path - requeuing I/O
nvme6c6n1: Read(0x2) @ LBA 2096384, 128 blocks, Host Aborted Command (sct 0x3 / sc 0x71)
blk_print_req_error: 1 callbacks suppressed
I/O error, dev nvme6c6n1, sector 2096384 op 0x0:(READ) flags 0x2880700 phys_seg 1 prio class 2
block nvme6n1: no usable path - requeuing I/O
Kernel attempted to read user page (236) - exploit attempt? (uid: 0)
BUG: Kernel NULL pointer dereference on read at 0x00000236
Faulting instruction address: 0xc000000000961274
Oops: Kernel access of bad area, sig: 11 [#1]
LE PAGE_SIZE=64K MMU=Radix  SMP NR_CPUS=2048 NUMA pSeries
Modules linked in: nvme_loop nvme_fabrics loop nvmet null_blk rpadlpar_io rpaphp xsk_diag bonding rfkill nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nf_tables nfnetlink pseries_rng dax_pmem vmx_crypto drm drm_panel_orientation_quirks xfs mlx5_core nvme bnx2x sd_mod nd_pmem nd_btt nvme_core sg papr_scm tls libnvdimm ibmvscsi ibmveth scsi_transport_srp nvme_keyring nvme_auth mdio hkdf pseries_wdt dm_mirror dm_region_hash dm_log dm_mod fuse [last unloaded: loop]
CPU: 25 UID: 0 PID: 0 Comm: swapper/25 Kdump: loaded Not tainted 7.0.0-rc3+ #14 PREEMPT
Hardware name: IBM,9043-MRX Power11 (architected) 0x820200 0xf000007 of:IBM,FW1120.00 (RF1120_128) hv:phyp pSeries
NIP:  c000000000961274 LR: c008000009af1808 CTR: c00000000096124c
REGS: c0000007ffc0f910 TRAP: 0300   Not tainted  (7.0.0-rc3+)
MSR:  8000000000009033 <SF,EE,ME,IR,DR,RI,LE>  CR: 22222222  XER: 00000000
CFAR: c008000009af232c DAR: 0000000000000236 DSISR: 40000000 IRQMASK: 0
GPR00: c008000009af17fc c0000007ffc0fbb0 c000000001c78100 c0000000be05cc00
GPR04: 0000000000000001 0000000000000000 0000000000000007 0000000000000000
GPR08: 0000000000000000 0000000000000000 0000000000000002 c008000009af2318
GPR12: c00000000096124c c0000007ffdab880 0000000000000000 0000000000000000
GPR16: 0000000000000010 0000000000000000 0000000000000004 0000000000000000
GPR20: 0000000000000001 c000000002ca2b00 0000000100043bb2 000000000000000a
GPR24: 000000000000000a 0000000000000000 0000000000000000 0000000000000000
GPR28: c000000084021d40 c000000084021d50 c0000000be05cd60 c0000000be05cc00
NIP [c000000000961274] blk_mq_complete_request_remote+0x28/0x2d4
LR [c008000009af1808] nvme_loop_queue_response+0x110/0x290 [nvme_loop]
Call Trace:
 0xc00000000502c640 (unreliable)
 nvme_loop_queue_response+0x104/0x290 [nvme_loop]
 __nvmet_req_complete+0x80/0x498 [nvmet]
 nvmet_req_complete+0x24/0xf8 [nvmet]
 nvmet_bio_done+0x58/0xcc [nvmet]
 bio_endio+0x250/0x390
 blk_update_request+0x2e8/0x68c
 blk_mq_end_request+0x30/0x5c
 lo_complete_rq+0x94/0x110 [loop]
 blk_complete_reqs+0x78/0x98
 handle_softirqs+0x148/0x454
 do_softirq_own_stack+0x3c/0x50
 __irq_exit_rcu+0x18c/0x1b4
 irq_exit+0x1c/0x34
 do_IRQ+0x114/0x278
 hardware_interrupt_common_virt+0x28c/0x290

Since the queue teardown path already guarantees that all target-side
operations have completed, cancelling the tagsets is redundant and
unsafe. So avoid cancelling the I/O and admin tagsets during controller
reset and shutdown.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme: add WQ_PERCPU to alloc_workqueue users
Marco Crivellari [Mon, 23 Feb 2026 10:23:28 +0000 (11:23 +0100)] 
nvme: add WQ_PERCPU to alloc_workqueue users

This continues the effort to refactor workqueue APIs, which began with
the introduction of new workqueues and a new alloc_workqueue flag in:

   commit 128ea9f6ccfb ("workqueue: Add system_percpu_wq and system_dfl_wq")
   commit 930c2ea566af ("workqueue: Add new WQ_PERCPU flag")

The refactoring is going to alter the default behavior of
alloc_workqueue() to be unbound by default.

With the introduction of the WQ_PERCPU flag (equivalent to !WQ_UNBOUND),
any alloc_workqueue() caller that doesn’t explicitly specify WQ_UNBOUND
must now use WQ_PERCPU. For more details see the Link tag below.

In order to keep alloc_workqueue() behavior identical, explicitly request
WQ_PERCPU.

Link: https://lore.kernel.org/all/20250221112003.1dSuoGyc@linutronix.de/
Suggested-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvmet-fc: add WQ_PERCPU to alloc_workqueue users
Marco Crivellari [Mon, 23 Feb 2026 10:23:29 +0000 (11:23 +0100)] 
nvmet-fc: add WQ_PERCPU to alloc_workqueue users

This continues the effort to refactor workqueue APIs, which began with
the introduction of new workqueues and a new alloc_workqueue flag in:

   commit 128ea9f6ccfb ("workqueue: Add system_percpu_wq and system_dfl_wq")
   commit 930c2ea566af ("workqueue: Add new WQ_PERCPU flag")

The refactoring is going to alter the default behavior of
alloc_workqueue() to be unbound by default.

With the introduction of the WQ_PERCPU flag (equivalent to !WQ_UNBOUND),
any alloc_workqueue() caller that doesn’t explicitly specify WQ_UNBOUND
must now use WQ_PERCPU. For more details see the Link tag below.

In order to keep alloc_workqueue() behavior identical, explicitly request
WQ_PERCPU.

Cc: Justin Tee <justin.tee@broadcom.com>
Cc: Naresh Gottumukkala <nareshgottumukkala83@gmail.com>
CC: Paul Ely <paul.ely@broadcom.com>
Link: https://lore.kernel.org/all/20250221112003.1dSuoGyc@linutronix.de/
Suggested-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvmet: replace use of system_wq with system_percpu_wq
Marco Crivellari [Mon, 23 Feb 2026 10:23:27 +0000 (11:23 +0100)] 
nvmet: replace use of system_wq with system_percpu_wq

This patch continues the effort to refactor workqueue APIs, which has begun
with the changes introducing new workqueues and a new alloc_workqueue flag:

   commit 128ea9f6ccfb ("workqueue: Add system_percpu_wq and system_dfl_wq")
   commit 930c2ea566af ("workqueue: Add new WQ_PERCPU flag")

The point of the refactoring is to eventually alter the default behavior of
workqueues to become unbound by default so that their workload placement is
optimized by the scheduler.

Before that to happen, workqueue users must be converted to the better named
new workqueues with no intended behaviour changes:

   system_wq -> system_percpu_wq
   system_unbound_wq -> system_dfl_wq

This way the old obsolete workqueues (system_wq, system_unbound_wq) can be
removed in the future.

Link: https://lore.kernel.org/all/20250221112003.1dSuoGyc@linutronix.de/
Suggested-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme-auth: Don't propose NVME_AUTH_DHGROUP_NULL with SC_C
Alistair Francis [Fri, 20 Mar 2026 00:20:45 +0000 (10:20 +1000)] 
nvme-auth: Don't propose NVME_AUTH_DHGROUP_NULL with SC_C

Section 8.3.4.5.2 of the NVMe 2.1 base spec states that

"""
The 00h identifier shall not be proposed in an AUTH_Negotiate message
that requests secure channel concatenation (i.e., with the SC_C field
set to a non-zero value).
"""

We need to ensure that we don't set the NVME_AUTH_DHGROUP_NULL idlist if
SC_C is set.

Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Chris Leech <cleech@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kamaljit Singh <kamaljit.singh@opensource.wdc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme: Add the DHCHAP maximum HD IDs
Alistair Francis [Fri, 20 Mar 2026 00:20:44 +0000 (10:20 +1000)] 
nvme: Add the DHCHAP maximum HD IDs

In preperation for using DHCHAP length in upcoming host and target
patches let's add the hash and diffie-hellman ID length macros.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Yunje Shin <ioerts@kookmin.ac.kr>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Chris Leech <cleech@redhat.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme-pci: add NVME_QUIRK_DISABLE_WRITE_ZEROES for Kingston OM3SGP4
Robert Beckett [Fri, 20 Mar 2026 19:22:09 +0000 (19:22 +0000)] 
nvme-pci: add NVME_QUIRK_DISABLE_WRITE_ZEROES for Kingston OM3SGP4

The Kingston OM3SGP42048K2-A00 (PCI ID 2646:502f) firmware has a race
condition when processing concurrent write zeroes and DSM (discard)
commands, causing spurious "LBA Out of Range" errors and IOMMU page
faults at address 0x0.

The issue is reliably triggered by running two concurrent mkfs commands
on different partitions of the same drive, which generates interleaved
write zeroes and discard operations.

Disable write zeroes for this device, matching the pattern used for
other Kingston OM* drives that have similar firmware issues.

Cc: stable@vger.kernel.org
Signed-off-by: Robert Beckett <bob.beckett@collabora.com>
Assisted-by: claude-opus-4-6-v1
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme: respect NVME_QUIRK_DISABLE_WRITE_ZEROES when wzsl is set
Robert Beckett [Fri, 20 Mar 2026 19:22:08 +0000 (19:22 +0000)] 
nvme: respect NVME_QUIRK_DISABLE_WRITE_ZEROES when wzsl is set

The NVM Command Set Identify Controller data may report a non-zero
Write Zeroes Size Limit (wzsl). When present, nvme_init_non_mdts_limits()
unconditionally overrides max_zeroes_sectors from wzsl, even if
NVME_QUIRK_DISABLE_WRITE_ZEROES previously set it to zero.

This effectively re-enables write zeroes for devices that need it
disabled, defeating the quirk. Several Kingston OM* drives rely on
this quirk to avoid firmware issues with write zeroes commands.

Check for the quirk before applying the wzsl override.

Fixes: 5befc7c26e5a ("nvme: implement non-mdts command limits")
Cc: stable@vger.kernel.org
Signed-off-by: Robert Beckett <bob.beckett@collabora.com>
Assisted-by: claude-opus-4-6-v1
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvmet: report NPDGL and NPDAL
Caleb Sander Mateos [Fri, 27 Feb 2026 20:23:53 +0000 (13:23 -0700)] 
nvmet: report NPDGL and NPDAL

A block device with a very large discard_granularity queue limit may not
be able to report it in the 16-bit NPDG and NPDA fields in the Identify
Namespace data structure. For this reason, version 2.1 of the NVMe specs
added 32-bit fields NPDGL and NPDAL to the NVM Command Set Specific
Identify Namespace structure. So report the discard_granularity there
too and set OPTPERF to 11b to indicate those fields are supported.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvmet: use NVME_NS_FEAT_OPTPERF_SHIFT
Caleb Sander Mateos [Fri, 27 Feb 2026 20:23:52 +0000 (13:23 -0700)] 
nvmet: use NVME_NS_FEAT_OPTPERF_SHIFT

Use the NVME_NS_FEAT_OPTPERF_SHIFT constant in nvmet_bdev_set_limits()
to set the OPTPERF bits of the nvme_id_ns NSFEAT field instead of the
magic number 4.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme: set discard_granularity from NPDG/NPDA
Caleb Sander Mateos [Fri, 27 Feb 2026 20:23:51 +0000 (13:23 -0700)] 
nvme: set discard_granularity from NPDG/NPDA

Currently, nvme_config_discard() always sets the discard_granularity
queue limit to the logical block size. However, NVMe namespaces can
advertise a larger preferred discard granularity in the NPDG or NPDA
field of the Identify Namespace structure or the NPDGL or NPDAL fields
of the I/O Command Set Specific Identify Namespace structure.

Use these fields to compute the discard_granularity limit. The logic is
somewhat involved. First, the fields are optional. NPDG is only reported
if the low bit of OPTPERF is set in NSFEAT. NPDA is reported if any bit
of OPTPERF is set. And NPDGL and NPDAL are reported if the high bit of
OPTPERF is set. NPDGL and NPDAL can also each be set to 0 to opt out of
reporting a limit. I/O Command Set Specific Identify Namespace may also
not be supported by older NVMe controllers. Another complication is that
multiple values may be reported among NPDG, NPDGL, NPDA, and NPDAL. The
spec says to prefer the values reported in the L variants. The spec says
NPDG should be a multiple of NPDA and NPDGL should be a multiple of
NPDAL, but it doesn't specify a relationship between NPDG and NPDAL or
NPDGL and NPDA. So use the maximum of the reported NPDG(L) and NPDA(L)
values as the discard_granularity.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme: add from0based() helper
Caleb Sander Mateos [Fri, 27 Feb 2026 20:23:50 +0000 (13:23 -0700)] 
nvme: add from0based() helper

The NVMe specifications are big fans of "0's based"/"0-based" fields for
encoding values that must be positive. The encoded value is 1 less than
the value it represents. nvmet already provides a helper to0based() for
encoding 0's based values, so add a corresponding helper to decode these
fields on the host side.

Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme: always issue I/O Command Set specific Identify Namespace
Caleb Sander Mateos [Fri, 27 Feb 2026 20:23:49 +0000 (13:23 -0700)] 
nvme: always issue I/O Command Set specific Identify Namespace

Currently, the I/O Command Set specific Identify Namespace structure is
only fetched for controllers that support extended LBA formats. This is
because struct nvme_id_ns_nvm is only used by nvme_configure_pi_elbas(),
which is only called when the ELBAS bit is set in the CTRATT field of
the Identify Controller structure.

However, the I/O Command Set specific Identify Namespace structure will
soon be used in nvme_update_disk_info(), so always try to obtain it in
nvme_update_ns_info_block(). This Identify structure is first defined in
NVMe spec version 2.0, but controllers reporting older versions could
still implement it.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme: update nvme_id_ns OPTPERF constants
Caleb Sander Mateos [Fri, 27 Feb 2026 20:23:48 +0000 (13:23 -0700)] 
nvme: update nvme_id_ns OPTPERF constants

In NVMe verson 2.0 and below, OPTPERF comprises only bit 4 of NSFEAT in
the Identify Namespace structure. Since version 2.1, OPTPERF includes
both bits 4 and 5 of NSFEAT. Replace the NVME_NS_FEAT_IO_OPT constant
with NVME_NS_FEAT_OPTPERF_SHIFT, NVME_NS_FEAT_OPTPERF_MASK, and
NVME_NS_FEAT_OPTPERF_MASK_2_1, representing the first bit, pre-2.1 bit
width, and post-2.1 bit width of OPTPERF.

Update nvme_update_disk_info() to check both OPTPERF bits for
controllers that report version 2.1 or newer, as NPWG and NOWS are
supported even if only bit 5 is set.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme: fold nvme_config_discard() into nvme_update_disk_info()
Caleb Sander Mateos [Fri, 27 Feb 2026 20:23:47 +0000 (13:23 -0700)] 
nvme: fold nvme_config_discard() into nvme_update_disk_info()

The choice of what queue limits are set in nvme_update_disk_info() vs.
nvme_config_discard() seems a bit arbitrary. A subsequent commit will
compute the discard_granularity limit using struct nvme_id_ns, which is
only passed to nvme_update_disk_info() currently. So move the logic in
nvme_config_discard() to nvme_update_disk_info(). Replace several
instances of ns->ctrl in nvme_update_disk_info() with the ctrl variable
brought from nvme_config_discard().

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme: add preferred I/O size fields to struct nvme_id_ns_nvm
Caleb Sander Mateos [Fri, 27 Feb 2026 20:23:46 +0000 (13:23 -0700)] 
nvme: add preferred I/O size fields to struct nvme_id_ns_nvm

A subsequent change will use the NPDGL and NPDAL fields of the NVM
Command Set Specific Identify Namespace structure, so add them (and the
handful of intervening fields) to struct nvme_id_ns_nvm. Add an
assertion that the size is still 4 KB.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme: Allow reauth from sysfs
Alistair Francis [Tue, 2 Dec 2025 05:17:55 +0000 (15:17 +1000)] 
nvme: Allow reauth from sysfs

Allow userspace to trigger a reauth (REPLACETLSPSK) from sysfs.
This can be done by writing  a zero to the sysfs file.

echo 0 > /sys/devices/virtual/nvme-fabrics/ctl/nvme0/tls_configured_key

In order to use the new keys for the admin queue we call controller
reset. This isn't ideal, but I can't find a simpler way to reset the
admin queue TLS connection.

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme: Expose the tls_configured sysfs for secure concat connections
Alistair Francis [Tue, 2 Dec 2025 05:17:54 +0000 (15:17 +1000)] 
nvme: Expose the tls_configured sysfs for secure concat connections

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvmet-tcp: Don't free SQ on authentication success
Alistair Francis [Tue, 2 Dec 2025 05:17:53 +0000 (15:17 +1000)] 
nvmet-tcp: Don't free SQ on authentication success

Curently after the host sends a REPLACETLSPSK we free the TLS keys as
part of calling nvmet_auth_sq_free() on success. This means when the
host sends a follow up REPLACETLSPSK we return CONCAT_MISMATCH as the
check for !nvmet_queue_tls_keyid(req->sq) fails.

This patch ensures we don't free the TLS key on success as we might need
it again in the future.

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvmet-tcp: Don't error if TLS is enabed on a reset
Alistair Francis [Tue, 2 Dec 2025 05:17:52 +0000 (15:17 +1000)] 
nvmet-tcp: Don't error if TLS is enabed on a reset

If the host sends a AUTH_Negotiate Message on the admin queue with
REPLACETLSPSK set then we expect and require a TLS connection and
shouldn't report an error if TLS is enabled.

This change only enforces the nvmet_queue_tls_keyid() check if we aren't
resetting the negotiation.

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agocrypto: remove HKDF library
Eric Biggers [Mon, 2 Mar 2026 07:59:59 +0000 (23:59 -0800)] 
crypto: remove HKDF library

Remove crypto/hkdf.c, since it's no longer used.  Originally it had two
users, but now both of them just inline the needed HMAC computations
using the HMAC library APIs.  That ends up being better, since it
eliminates all the complexity and performance issues associated with the
crypto_shash abstraction and multi-step HMAC input formatting.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme-auth: common: remove selections of no-longer used crypto modules
Eric Biggers [Mon, 2 Mar 2026 07:59:58 +0000 (23:59 -0800)] 
nvme-auth: common: remove selections of no-longer used crypto modules

Now that nvme-auth uses the crypto library instead of crypto_shash,
remove obsolete selections from the NVME_AUTH kconfig option.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme-auth: common: remove nvme_auth_digest_name()
Eric Biggers [Mon, 2 Mar 2026 07:59:57 +0000 (23:59 -0800)] 
nvme-auth: common: remove nvme_auth_digest_name()

Since nvme_auth_digest_name() is no longer used, remove it and the
associated data from the hash_map array.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme-auth: target: use crypto library in nvmet_auth_ctrl_hash()
Eric Biggers [Mon, 2 Mar 2026 07:59:56 +0000 (23:59 -0800)] 
nvme-auth: target: use crypto library in nvmet_auth_ctrl_hash()

For the HMAC computation in nvmet_auth_ctrl_hash(), use the crypto
library instead of crypto_shash.  This is simpler, faster, and more
reliable.  Notably, this eliminates the crypto transformation object
allocation for every call, which was very slow.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme-auth: target: use crypto library in nvmet_auth_host_hash()
Eric Biggers [Mon, 2 Mar 2026 07:59:55 +0000 (23:59 -0800)] 
nvme-auth: target: use crypto library in nvmet_auth_host_hash()

For the HMAC computation in nvmet_auth_host_hash(), use the crypto
library instead of crypto_shash.  This is simpler, faster, and more
reliable.  Notably, this eliminates the crypto transformation object
allocation for every call, which was very slow.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme-auth: target: remove obsolete crypto_has_shash() checks
Eric Biggers [Mon, 2 Mar 2026 07:59:54 +0000 (23:59 -0800)] 
nvme-auth: target: remove obsolete crypto_has_shash() checks

Since nvme-auth is now doing its HMAC computations using the crypto
library, it's guaranteed that all the algorithms actually work.
Therefore, remove the crypto_has_shash() checks which are now obsolete.

However, the caller in nvmet_auth_negotiate() seems to have also been
relying on crypto_has_shash(nvme_auth_hmac_name(host_hmac_id)) to
validate the host_hmac_id.  Therefore, make it validate the ID more
directly by checking whether nvme_auth_hmac_hash_len() returns 0 or not.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme-auth: host: remove allocation of crypto_shash
Eric Biggers [Mon, 2 Mar 2026 07:59:53 +0000 (23:59 -0800)] 
nvme-auth: host: remove allocation of crypto_shash

Now that the crypto_shash that is being allocated in
nvme_auth_process_dhchap_challenge() and stored in the
struct nvme_dhchap_queue_context is no longer used, remove it.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme-auth: host: use crypto library in nvme_auth_dhchap_setup_ctrl_response()
Eric Biggers [Mon, 2 Mar 2026 07:59:52 +0000 (23:59 -0800)] 
nvme-auth: host: use crypto library in nvme_auth_dhchap_setup_ctrl_response()

For the HMAC computation in nvme_auth_dhchap_setup_ctrl_response(), use
the crypto library instead of crypto_shash.  This is simpler, faster,
and more reliable.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme-auth: host: use crypto library in nvme_auth_dhchap_setup_host_response()
Eric Biggers [Mon, 2 Mar 2026 07:59:51 +0000 (23:59 -0800)] 
nvme-auth: host: use crypto library in nvme_auth_dhchap_setup_host_response()

For the HMAC computation in nvme_auth_dhchap_setup_host_response(), use
the crypto library instead of crypto_shash.  This is simpler, faster,
and more reliable.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme-auth: common: use crypto library in nvme_auth_derive_tls_psk()
Eric Biggers [Mon, 2 Mar 2026 07:59:50 +0000 (23:59 -0800)] 
nvme-auth: common: use crypto library in nvme_auth_derive_tls_psk()

For the HKDF-Expand-Label computation in nvme_auth_derive_tls_psk(), use
the crypto library instead of crypto_shash and crypto/hkdf.c.

While this means the HKDF "helper" functions are no longer utilized,
they clearly weren't buying us much: it's simpler to just inline the
HMAC computations directly, and this code needs to be tested anyway.  (A
similar result was seen in fs/crypto/.  As a result, this eliminates the
last user of crypto/hkdf.c, which we'll be able to remove as well.)

As usual this is also a lot more efficient, eliminating the allocation
of a transformation object and multiple other dynamic allocations.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme-auth: common: use crypto library in nvme_auth_generate_digest()
Eric Biggers [Mon, 2 Mar 2026 07:59:49 +0000 (23:59 -0800)] 
nvme-auth: common: use crypto library in nvme_auth_generate_digest()

For the HMAC computation in nvme_auth_generate_digest(), use the crypto
library instead of crypto_shash.  This is simpler, faster, and more
reliable.  Notably, this eliminates the crypto transformation object
allocation for every call, which was very slow.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme-auth: common: use crypto library in nvme_auth_generate_psk()
Eric Biggers [Mon, 2 Mar 2026 07:59:48 +0000 (23:59 -0800)] 
nvme-auth: common: use crypto library in nvme_auth_generate_psk()

For the HMAC computation in nvme_auth_generate_psk(), use the crypto
library instead of crypto_shash.  This is simpler, faster, and more
reliable.  Notably, this eliminates the crypto transformation object
allocation for every call, which was very slow.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme-auth: common: use crypto library in nvme_auth_augmented_challenge()
Eric Biggers [Mon, 2 Mar 2026 07:59:47 +0000 (23:59 -0800)] 
nvme-auth: common: use crypto library in nvme_auth_augmented_challenge()

For the hash and HMAC computations in nvme_auth_augmented_challenge(),
use the crypto library instead of crypto_shash.  This is simpler,
faster, and more reliable.  Notably, this eliminates two crypto
transformation object allocations for every call, which was very slow.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme-auth: common: use crypto library in nvme_auth_transform_key()
Eric Biggers [Mon, 2 Mar 2026 07:59:46 +0000 (23:59 -0800)] 
nvme-auth: common: use crypto library in nvme_auth_transform_key()

For the HMAC computation in nvme_auth_transform_key(), use the crypto
library instead of crypto_shash.  This is simpler, faster, and more
reliable.  Notably, this eliminates the transformation object allocation
for every call, which was very slow.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme-auth: common: add HMAC helper functions
Eric Biggers [Mon, 2 Mar 2026 07:59:45 +0000 (23:59 -0800)] 
nvme-auth: common: add HMAC helper functions

Add some helper functions for computing HMAC-SHA256, HMAC-SHA384, or
HMAC-SHA512 values using the crypto library instead of crypto_shash.
These will enable some significant simplifications and performance
improvements in nvme-auth.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme-auth: common: explicitly verify psk_len == hash_len
Eric Biggers [Mon, 2 Mar 2026 07:59:44 +0000 (23:59 -0800)] 
nvme-auth: common: explicitly verify psk_len == hash_len

nvme_auth_derive_tls_psk() is always called with psk_len == hash_len.
And based on the comments above nvme_auth_generate_psk() and
nvme_auth_derive_tls_psk(), this isn't an implementation choice but
rather just the length the spec uses.  Add a check which makes this
explicit, so that when cleaning up nvme_auth_derive_tls_psk() we don't
have to retain support for arbitrary values of psk_len.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme-auth: rename nvme_auth_generate_key() to nvme_auth_parse_key()
Eric Biggers [Mon, 2 Mar 2026 07:59:43 +0000 (23:59 -0800)] 
nvme-auth: rename nvme_auth_generate_key() to nvme_auth_parse_key()

This function does not generate a key.  It parses the key from the
string that the caller passes in.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme-auth: common: add KUnit tests for TLS key derivation
Eric Biggers [Mon, 2 Mar 2026 07:59:42 +0000 (23:59 -0800)] 
nvme-auth: common: add KUnit tests for TLS key derivation

Unit-test the sequence of function calls that derive tls_psk, so that we
can be more confident that changes in the implementation don't break it.

Since the NVMe specification doesn't seem to include any test vectors
for this (nor does its description of the algorithm seem to match what
was actually implemented, for that matter), I just set the expected
values to the values that the code currently produces.  In the case
of SHA-512, nvme_auth_generate_digest() currently returns -EINVAL, so
for now the test tests for that too.  If it is later determined that
some other behavior is needed, the test can be updated accordingly.

Tested with:

    tools/testing/kunit/kunit.py run --kunitconfig drivers/nvme/common/

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme-auth: use proper argument types
Eric Biggers [Mon, 2 Mar 2026 07:59:41 +0000 (23:59 -0800)] 
nvme-auth: use proper argument types

For input parameters, use pointer to const.  This makes it easier to
understand which parameters are inputs and which are outputs.

In addition, consistently use char for strings and u8 for binary.  This
makes it easier to understand what is a string and what is binary data.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme-auth: common: constify static data
Eric Biggers [Mon, 2 Mar 2026 07:59:40 +0000 (23:59 -0800)] 
nvme-auth: common: constify static data

Fully constify the dhgroup_map and hash_map arrays.  Remove 'const' from
individual fields, as it is now redundant.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agonvme-auth: add NVME_AUTH_MAX_DIGEST_SIZE constant
Eric Biggers [Mon, 2 Mar 2026 07:59:39 +0000 (23:59 -0800)] 
nvme-auth: add NVME_AUTH_MAX_DIGEST_SIZE constant

Define a NVME_AUTH_MAX_DIGEST_SIZE constant and use it in the
appropriate places.

Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>
2 months agodrbd: Balance RCU calls in drbd_adm_dump_devices()
Bart Van Assche [Thu, 26 Mar 2026 21:40:54 +0000 (14:40 -0700)] 
drbd: Balance RCU calls in drbd_adm_dump_devices()

Make drbd_adm_dump_devices() call rcu_read_lock() before
rcu_read_unlock() is called. This has been detected by the Clang
thread-safety analyzer.

Tested-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Fixes: a55bbd375d18 ("drbd: Backport the "status" command")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/20260326214054.284593-1-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2 months agodrbd: use genl pre_doit/post_doit
Christoph Böhmwalder [Tue, 24 Mar 2026 15:29:07 +0000 (16:29 +0100)] 
drbd: use genl pre_doit/post_doit

Every doit handler followed the same pattern: stack-allocate an
adm_ctx, call drbd_adm_prepare() at the top, call drbd_adm_finish()
at the bottom. This duplicated boilerplate across 25 handlers and
made error paths inconsistent, since some handlers could miss sending
the reply skb on early-exit paths.

The generic netlink framework already provides pre_doit/post_doit
hooks for exactly this purpose. An old comment even noted "this
would be a good candidate for a pre_doit hook".

Use them:

- pre_doit heap-allocates adm_ctx, looks up per-command flags from a
  new drbd_genl_cmd_flags[] table, runs drbd_adm_prepare(), and
  stores the context in info->user_ptr[0].
- post_doit sends the reply, drops kref references for
  device/connection/resource, and frees the adm_ctx.
- Handlers just receive adm_ctx from info->user_ptr[0], set
  reply_dh->ret_code, and return. All teardown is in post_doit.
- drbd_adm_finish() is removed, superseded by post_doit.

Signed-off-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com>
Link: https://patch.msgid.link/20260324152907.2840984-1-christoph.boehmwalder@linbit.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2 months agozloop: forget write cache on force removal
Christoph Hellwig [Mon, 23 Mar 2026 07:11:50 +0000 (08:11 +0100)] 
zloop: forget write cache on force removal

Add a new options that causes zloop to truncate the zone files to the
write pointer value recorded at the last cache flush to simulate
unclean shutdowns.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://patch.msgid.link/20260323071156.2940772-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2 months agozloop: refactor zloop_rw
Christoph Hellwig [Mon, 23 Mar 2026 07:11:49 +0000 (08:11 +0100)] 
zloop: refactor zloop_rw

Split out two helpers functions to make the function more readable and
to avoid conditional locking.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://patch.msgid.link/20260323071156.2940772-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2 months agoblock: fix bio_alloc_bioset slowpath GFP handling
Vasily Gorbik [Sun, 22 Mar 2026 02:35:10 +0000 (03:35 +0100)] 
block: fix bio_alloc_bioset slowpath GFP handling

bio_alloc_bioset() first strips __GFP_DIRECT_RECLAIM from the optimistic
fast allocation attempt with try_alloc_gfp(). If that fast path fails,
the slowpath checks saved_gfp to decide whether blocking allocation is
allowed, but then still calls mempool_alloc() with the stripped gfp mask.
That can lead to a NULL bio pointer being passed into bio_init().

Fix the slowpath by using saved_gfp for the bio and bvec mempool
allocations.

Fixes: b520c4eef83d ("block: split bio_alloc_bioset more clearly into a fast and slowpath")
Reported-by: syzbot+09ddb593eea76a158f42@syzkaller.appspotmail.com
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/p01.gc6e9ad5845ad.ttca29g@ub.hpns
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2 months agoublk: move cold paths out of __ublk_batch_dispatch() for icache efficiency
Ming Lei [Wed, 18 Mar 2026 01:41:12 +0000 (09:41 +0800)] 
ublk: move cold paths out of __ublk_batch_dispatch() for icache efficiency

Mark ublk_filter_unused_tags() as noinline since it is only called from
the unlikely(needs_filter) branch. Extract the error-handling block from
__ublk_batch_dispatch() into a new noinline ublk_batch_dispatch_fail()
function to keep the hot path compact and icache-friendly. This also
makes __ublk_batch_dispatch() more readable by separating the error
recovery logic from the normal dispatch flow.

Before: __ublk_batch_dispatch is ~1419 bytes
After:  __ublk_batch_dispatch is ~1090 bytes (-329 bytes, -23%)

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://patch.msgid.link/20260318014112.3125432-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2 months agoMerge tag 'md-7.1-20260323' of git://git.kernel.org/pub/scm/linux/kernel/git/mdraid...
Jens Axboe [Sun, 22 Mar 2026 19:37:45 +0000 (13:37 -0600)] 
Merge tag 'md-7.1-20260323' of git://git.kernel.org/pub/scm/linux/kernel/git/mdraid/linux into for-7.1/block

Pull MD changes from Yu Kuia:

"Bug Fixes:
 - md: suppress spurious superblock update error message for dm-raid
   (Chen Cheng)
 - md/raid1: fix the comparing region of interval tree (Xiao Ni)
 - md/raid10: fix deadlock with check operation and nowait requests
   (Josh Hunt)
 - md/raid5: skip 2-failure compute when other disk is R5_LOCKED
   (FengWei Shih)
 - md/md-llbitmap: raise barrier before state machine transition
   (Yu Kuai)
 - md/md-llbitmap: skip reading rdevs that are not in_sync (Yu Kuai)

 Improvements:
 - md/raid5: set chunk_sectors to enable full stripe I/O splitting
   (Yu Kuai)

 Cleanups:
 - md: remove unused mddev argument from export_rdev (Chen Cheng)
 - md/raid5: remove stale md_raid5_kick_device() declaration
   (Chen Cheng)
 - md/raid5: move handle_stripe() comment to correct location
   (Chen Cheng)"

* tag 'md-7.1-20260323' of git://git.kernel.org/pub/scm/linux/kernel/git/mdraid/linux:
  md: remove unused mddev argument from export_rdev
  md/raid5: move handle_stripe() comment to correct location
  md/raid5: remove stale md_raid5_kick_device() declaration
  md/raid1: fix the comparing region of interval tree
  md/raid5: skip 2-failure compute when other disk is R5_LOCKED
  md/md-llbitmap: raise barrier before state machine transition
  md/md-llbitmap: skip reading rdevs that are not in_sync
  md/raid5: set chunk_sectors to enable full stripe I/O splitting
  md/raid10: fix deadlock with check operation and nowait requests
  md: suppress spurious superblock update error message for dm-raid

2 months agomd: remove unused mddev argument from export_rdev
Chen Cheng [Wed, 4 Mar 2026 11:14:17 +0000 (19:14 +0800)] 
md: remove unused mddev argument from export_rdev

The mddev argument in export_rdev() is never used. Remove it to
simplify callers.

Signed-off-by: Chen Cheng <chencheng@fnnas.com>
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
Link: https://lore.kernel.org/linux-raid/20260304111417.20777-1-chencheng@fnnas.com/
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
2 months agomd/raid5: move handle_stripe() comment to correct location
Chen Cheng [Wed, 4 Mar 2026 11:10:01 +0000 (19:10 +0800)] 
md/raid5: move handle_stripe() comment to correct location

Move the handle_stripe() documentation comment from above
analyse_stripe() to directly above handle_stripe() where it belongs.

Signed-off-by: Chen Cheng <chencheng@fnnas.com>
Reviewed-by: Yu Kuai <yukuai@fnnas.com>
Link: https://lore.kernel.org/linux-raid/20260304111001.15767-1-chencheng@fnnas.com/
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
2 months agomd/raid5: remove stale md_raid5_kick_device() declaration
Chen Cheng [Wed, 4 Mar 2026 11:09:18 +0000 (19:09 +0800)] 
md/raid5: remove stale md_raid5_kick_device() declaration

Remove the unused md_raid5_kick_device() declaration from raid5.h -
no definition exists for this function.

Signed-off-by: Chen Cheng <chencheng@fnnas.com>
Reviewed-by: Yu Kuai <yukuai@fnnas.com>
Link: https://lore.kernel.org/linux-raid/20260304110919.15071-1-chencheng@fnnas.com/
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
2 months agomd/raid1: fix the comparing region of interval tree
Xiao Ni [Thu, 5 Mar 2026 01:18:33 +0000 (09:18 +0800)] 
md/raid1: fix the comparing region of interval tree

Interval tree uses [start, end] as a region which stores in the tree.
In raid1, it uses the wrong end value. For example:
bio(A,B) is too big and needs to be split to bio1(A,C-1), bio2(C,B).
The region of bio1 is [A,C] and the region of bio2 is [C,B]. So bio1 and
bio2 overlap which is not right.

Fix this problem by using right end value of the region.

Fixes: d0d2d8ba0494 ("md/raid1: introduce wait_for_serialization")
Signed-off-by: Xiao Ni <xni@redhat.com>
Link: https://lore.kernel.org/linux-raid/20260305011839.5118-2-xni@redhat.com/
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
2 months agomd/raid5: skip 2-failure compute when other disk is R5_LOCKED
FengWei Shih [Thu, 19 Mar 2026 05:33:51 +0000 (13:33 +0800)] 
md/raid5: skip 2-failure compute when other disk is R5_LOCKED

When skip_copy is enabled on a doubly-degraded RAID6, a device that is
being written to will be in R5_LOCKED state with R5_UPTODATE cleared.
If a new read triggers fetch_block() while the write is still in
flight, the 2-failure compute path may select this locked device as a
compute target because it is not R5_UPTODATE.

Because skip_copy makes the device page point directly to the bio page,
reconstructing data into it might be risky. Also, since the compute
marks the device R5_UPTODATE, it triggers WARN_ON in ops_run_io()
which checks that R5_SkipCopy and R5_UPTODATE are not both set.

This can be reproduced by running small-range concurrent read/write on
a doubly-degraded RAID6 with skip_copy enabled, for example:

  mdadm -C /dev/md0 -l6 -n6 -R -f /dev/loop[0-3] missing missing
  echo 1 > /sys/block/md0/md/skip_copy
  fio --filename=/dev/md0 --rw=randrw --bs=4k --numjobs=8 \
      --iodepth=32 --size=4M --runtime=30 --time_based --direct=1

Fix by checking R5_LOCKED before proceeding with the compute. The
compute will be retried once the lock is cleared on IO completion.

Signed-off-by: FengWei Shih <dannyshih@synology.com>
Reviewed-by: Yu Kuai <yukuai@fnnas.com>
Link: https://lore.kernel.org/linux-raid/20260319053351.3676794-1-dannyshih@synology.com/
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
2 months agoblock: partitions: Replace pp_buf with struct seq_buf
Kees Cook [Sat, 21 Mar 2026 00:48:44 +0000 (17:48 -0700)] 
block: partitions: Replace pp_buf with struct seq_buf

In preparation for removing the strlcat API[1], replace the char *pp_buf
with a struct seq_buf, which tracks the current write position and
remaining space internally. This allows for:

- Direct use of seq_buf_printf() in place of snprintf()+strlcat()
  pairs, eliminating local tmp buffers throughout.
- Adjacent strlcat() calls that build strings piece-by-piece
  (e.g., strlcat("["); strlcat(name); strlcat("]")) to be collapsed
  into single seq_buf_printf() calls.
- Simpler call sites: seq_buf_puts() takes only the buffer and string,
  with no need to pass PAGE_SIZE at every call.

The backing buffer allocation is unchanged (__get_free_page), and the
output path uses seq_buf_str() to NUL-terminate before passing to
printk().

Link: https://github.com/KSPP/linux/issues/370
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Josh Law <objecting@objecting.org>
Signed-off-by: Kees Cook <kees@kernel.org>
Reviewed-by: Josh Law <objecting@objecting.org>
Link: https://patch.msgid.link/20260321004840.work.670-kees@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2 months agoscsi: bsg: add io_uring passthrough handler
Yang Xiuwei [Tue, 17 Mar 2026 07:22:26 +0000 (15:22 +0800)] 
scsi: bsg: add io_uring passthrough handler

Implement the SCSI-specific io_uring command handler for BSG using
struct bsg_uring_cmd.

The handler builds a SCSI request from the io_uring command, maps user
buffers (including fixed buffers), and completes asynchronously via a
request end_io callback and task_work. Completion returns a 32-bit
status and packed residual/sense information via CQE res and res2, and
supports IO_URING_F_NONBLOCK.

Signed-off-by: Yang Xiuwei <yangxiuwei@kylinos.cn>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/20260317072226.2598233-4-yangxiuwei@kylinos.cn
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2 months agobsg: add io_uring command support to generic layer
Yang Xiuwei [Tue, 17 Mar 2026 07:22:25 +0000 (15:22 +0800)] 
bsg: add io_uring command support to generic layer

Add an io_uring command handler to the generic BSG layer. The new
.uring_cmd file operation validates io_uring features and delegates
handling to a per-queue bsg_uring_cmd_fn callback.

Extend bsg_register_queue() so transport drivers can register both
sg_io and io_uring command handlers.

Signed-off-by: Yang Xiuwei <yangxiuwei@kylinos.cn>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/20260317072226.2598233-3-yangxiuwei@kylinos.cn
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2 months agobsg: add bsg_uring_cmd uapi structure
Yang Xiuwei [Tue, 17 Mar 2026 07:22:24 +0000 (15:22 +0800)] 
bsg: add bsg_uring_cmd uapi structure

Add the bsg_uring_cmd structure to the BSG UAPI header to support
io_uring-based SCSI passthrough operations via IORING_OP_URING_CMD.

Signed-off-by: Yang Xiuwei <yangxiuwei@kylinos.cn>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/20260317072226.2598233-2-yangxiuwei@kylinos.cn
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2 months agoblock: reject zero length in bio_add_page()
Qu Wenruo [Tue, 17 Mar 2026 08:06:34 +0000 (18:36 +1030)] 
block: reject zero length in bio_add_page()

The function bio_add_page() returns the number of bytes added to the
bio, and if that failed it should return 0.

However there is a special quirk, if a caller is passing a page with
length 0, that function will always return 0 but with different results:

- The page is added to the bio
  If there is enough bvec slot or the folio can be merged with the last
  bvec.

  The return value 0 is just the length passed in, which is also 0.

- The page is not added to the bio
  If the page is not mergeable with the last bvec, or there is no bvec
  slot available.

  The return value 0 means page is not added into the bio.

Unfortunately the caller is not able to distinguish the above two cases,
and will treat the 0 return value as page addition failure.

In that case, this can lead to the double releasing of the last page:

- By the bio cleanup
  Which normally goes through every page of the bio, including the last
  page which is added into the bio.

- By the caller
  Which believes the page is not added into the bio, thus would manually
  release the page.

I do not think anyone should call bio_add_folio()/bio_add_page() with zero
length, but idiots like me can still show up.

So add an extra WARN_ON_ONCE() check for zero length and rejects it
early to avoid double freeing.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Link: https://patch.msgid.link/bc2223c080f38d0b63f968f605c918181c840f40.1773734749.git.wqu@suse.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2 months agoblk-mq: make blk_mq_hw_ctx_sysfs_entry instances const
Thomas Weißschuh [Mon, 16 Mar 2026 22:43:54 +0000 (23:43 +0100)] 
blk-mq: make blk_mq_hw_ctx_sysfs_entry instances const

The blk_mq_hw_ctx_sysfs_entry structures are never modified,
mark them as const.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Link: https://patch.msgid.link/20260316-b4-sysfs-const-attr-block-v1-4-a35d73b986b0@weissschuh.net
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2 months agoblk-crypto: make blk_crypto_attr instances const
Thomas Weißschuh [Mon, 16 Mar 2026 22:43:53 +0000 (23:43 +0100)] 
blk-crypto: make blk_crypto_attr instances const

The blk_crypto_attrs structures are never modified, mark them as const.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: John Garry <john.g.garry@oracle.com>>
Link: https://patch.msgid.link/20260316-b4-sysfs-const-attr-block-v1-3-a35d73b986b0@weissschuh.net
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2 months agoblock: ia-ranges: make blk_ia_range_sysfs_entry instances const
Thomas Weißschuh [Mon, 16 Mar 2026 22:43:52 +0000 (23:43 +0100)] 
block: ia-ranges: make blk_ia_range_sysfs_entry instances const

The blk_ia_range_sysfs_entry structures are never modified,
mark them as const.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Link: https://patch.msgid.link/20260316-b4-sysfs-const-attr-block-v1-2-a35d73b986b0@weissschuh.net
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2 months agoblock: make queue_sysfs_entry instances const
Thomas Weißschuh [Mon, 16 Mar 2026 22:43:51 +0000 (23:43 +0100)] 
block: make queue_sysfs_entry instances const

The queue_sysfs_entry structures are never modified, mark them as const.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Link: https://patch.msgid.link/20260316-b4-sysfs-const-attr-block-v1-1-a35d73b986b0@weissschuh.net
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2 months agoblock: remove bvec_free
Christoph Hellwig [Mon, 16 Mar 2026 16:11:31 +0000 (17:11 +0100)] 
block: remove bvec_free

bvec_free is only called by bio_free, so inline it there.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> -ck
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://patch.msgid.link/20260316161144.1607877-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2 months agoblock: split bio_alloc_bioset more clearly into a fast and slowpath
Christoph Hellwig [Mon, 16 Mar 2026 16:11:30 +0000 (17:11 +0100)] 
block: split bio_alloc_bioset more clearly into a fast and slowpath

bio_alloc_bioset tries non-waiting slab allocations first for the bio and
bvec array, but does so in a somewhat convoluted way.

Restructure the function so that it first open codes these slab
allocations, and then falls back to the mempools with the original
gfp mask.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> -ck
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://patch.msgid.link/20260316161144.1607877-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2 months agoblock: mark bvec_{alloc,free} static
Christoph Hellwig [Mon, 16 Mar 2026 16:11:29 +0000 (17:11 +0100)] 
block: mark bvec_{alloc,free} static

Only used in bio.c these days.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> -ck
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://patch.msgid.link/20260316161144.1607877-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2 months agomd/md-llbitmap: raise barrier before state machine transition
Yu Kuai [Mon, 23 Feb 2026 02:40:35 +0000 (10:40 +0800)] 
md/md-llbitmap: raise barrier before state machine transition

Move the barrier raise operation before calling llbitmap_state_machine()
in both llbitmap_start_write() and llbitmap_start_discard(). This
ensures the barrier is in place before any state transitions occur,
preventing potential race conditions where the state machine could
complete before the barrier is properly raised.

Cc: stable@vger.kernel.org
Fixes: 5ab829f1971d ("md/md-llbitmap: introduce new lockless bitmap")
Link: https://lore.kernel.org/linux-raid/20260223024038.3084853-3-yukuai@fnnas.com
Signed-off-by: Yu Kuai <yukuai@fnnas.com>
2 months agomd/md-llbitmap: skip reading rdevs that are not in_sync
Yu Kuai [Mon, 23 Feb 2026 02:40:34 +0000 (10:40 +0800)] 
md/md-llbitmap: skip reading rdevs that are not in_sync

When reading bitmap pages from member disks, the code iterates through
all rdevs and attempts to read from the first available one. However,
it only checks for raid_disk assignment and Faulty flag, missing the
In_sync flag check.

This can cause bitmap data to be read from spare disks that are still
being rebuilt and don't have valid bitmap information yet. Reading
stale or uninitialized bitmap data from such disks can lead to
incorrect dirty bit tracking, potentially causing data corruption
during recovery or normal operation.

Add the In_sync flag check to ensure bitmap pages are only read from
fully synchronized member disks that have valid bitmap data.

Cc: stable@vger.kernel.org
Fixes: 5ab829f1971d ("md/md-llbitmap: introduce new lockless bitmap")
Link: https://lore.kernel.org/linux-raid/20260223024038.3084853-2-yukuai@fnnas.com
Signed-off-by: Yu Kuai <yukuai@fnnas.com>
2 months agomd/raid5: set chunk_sectors to enable full stripe I/O splitting
Yu Kuai [Mon, 23 Feb 2026 03:58:34 +0000 (11:58 +0800)] 
md/raid5: set chunk_sectors to enable full stripe I/O splitting

Set chunk_sectors to the full stripe width (io_opt) so that the block
layer splits I/O at full stripe boundaries. This ensures that large
writes are aligned to full stripes, avoiding the read-modify-write
overhead that occurs with partial stripe writes in RAID-5/6.

When chunk_sectors is set, the block layer's bio splitting logic in
get_max_io_size() uses blk_boundary_sectors_left() to limit I/O size
to the boundary. This naturally aligns split bios to full stripe
boundaries, enabling more efficient full stripe writes.

Test results with 24-disk RAID5 (chunk_size=64k):
  dd if=/dev/zero of=/dev/md0 bs=10M oflag=direct
  Before: 461 MB/s
  After:  520 MB/s  (+12.8%)

Link: https://lore.kernel.org/linux-raid/20260223035834.3132498-1-yukuai@fnnas.com
Suggested-by: Christoph Hellwig <hch@infradead.org>
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Yu Kuai <yukuai@fnnas.com>
2 months agomd/raid10: fix deadlock with check operation and nowait requests
Josh Hunt [Tue, 3 Mar 2026 00:56:19 +0000 (19:56 -0500)] 
md/raid10: fix deadlock with check operation and nowait requests

When an array check is running it will raise the barrier at which point
normal requests will become blocked and increment the nr_pending value to
signal there is work pending inside of wait_barrier(). NOWAIT requests
do not block and so will return immediately with an error, and additionally
do not increment nr_pending in wait_barrier(). Upstream change commit
43806c3d5b9b ("raid10: cleanup memleak at raid10_make_request") added a
call to raid_end_bio_io() to fix a memory leak when NOWAIT requests hit
this condition. raid_end_bio_io() eventually calls allow_barrier() and
it will unconditionally do an atomic_dec_and_test(&conf->nr_pending) even
though the corresponding increment on nr_pending didn't happen in the
NOWAIT case.

This can be easily seen by starting a check operation while an application
is doing nowait IO on the same array. This results in a deadlocked state
due to nr_pending value underflowing and so the md resync thread gets stuck
waiting for nr_pending to == 0.

Output of r10conf state of the array when we hit this condition:

crash> struct r10conf
barrier = 1,
        nr_pending = {
          counter = -41
        },
        nr_waiting = 15,
        nr_queued = 0,

Example of md_sync thread stuck waiting on raise_barrier() and other
requests stuck in wait_barrier():

md1_resync
[<0>] raise_barrier+0xce/0x1c0
[<0>] raid10_sync_request+0x1ca/0x1ed0
[<0>] md_do_sync+0x779/0x1110
[<0>] md_thread+0x90/0x160
[<0>] kthread+0xbe/0xf0
[<0>] ret_from_fork+0x34/0x50
[<0>] ret_from_fork_asm+0x1a/0x30

kworker/u1040:2+flush-253:4
[<0>] wait_barrier+0x1de/0x220
[<0>] regular_request_wait+0x30/0x180
[<0>] raid10_make_request+0x261/0x1000
[<0>] md_handle_request+0x13b/0x230
[<0>] __submit_bio+0x107/0x1f0
[<0>] submit_bio_noacct_nocheck+0x16f/0x390
[<0>] ext4_io_submit+0x24/0x40
[<0>] ext4_do_writepages+0x254/0xc80
[<0>] ext4_writepages+0x84/0x120
[<0>] do_writepages+0x7a/0x260
[<0>] __writeback_single_inode+0x3d/0x300
[<0>] writeback_sb_inodes+0x1dd/0x470
[<0>] __writeback_inodes_wb+0x4c/0xe0
[<0>] wb_writeback+0x18b/0x2d0
[<0>] wb_workfn+0x2a1/0x400
[<0>] process_one_work+0x149/0x330
[<0>] worker_thread+0x2d2/0x410
[<0>] kthread+0xbe/0xf0
[<0>] ret_from_fork+0x34/0x50
[<0>] ret_from_fork_asm+0x1a/0x30

Fixes: 43806c3d5b9b ("raid10: cleanup memleak at raid10_make_request")
Cc: stable@vger.kernel.org
Signed-off-by: Josh Hunt <johunt@akamai.com>
Link: https://lore.kernel.org/linux-raid/20260303005619.1352958-1-johunt@akamai.com
Signed-off-by: Yu Kuai <yukuai@fnnas.com>
2 months agomd: suppress spurious superblock update error message for dm-raid
Chen Cheng [Tue, 10 Feb 2026 13:38:47 +0000 (21:38 +0800)] 
md: suppress spurious superblock update error message for dm-raid

dm-raid has external metadata management (mddev->external = 1) and
no persistent superblock (mddev->persistent = 0). For these arrays,
there's no superblock to update, so the error message is spurious.

The error appears as:
md_update_sb: can't update sb for read-only array md0

Fixes: 8c9e376b9d1a ("md: warn about updating super block failure")
Reported-by: Tj <tj.iam.tj@proton.me>
Closes: https://lore.kernel.org/all/20260128082430.96788-1-tj.iam.tj@proton.me/
Signed-off-by: Chen Cheng <chencheng@fnnas.com>
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
Link: https://lore.kernel.org/linux-raid/20260210133847.269986-1-chencheng@fnnas.com
Signed-off-by: Yu Kuai <yukuai@fnnas.com>
2 months agoublk: report BLK_SPLIT_INTERVAL_CAPABLE
Caleb Sander Mateos [Fri, 13 Mar 2026 14:47:01 +0000 (07:47 -0700)] 
ublk: report BLK_SPLIT_INTERVAL_CAPABLE

The ublk driver doesn't access request integrity buffers directly, it
only copies them to/from the ublk server in ublk_copy_user_integrity().
ublk_copy_user_integrity() uses bio_for_each_integrity_vec() to walk all
the integrity segments. ublk devices are therefore capable of handling
requests with integrity intervals split across segments. Set
BLK_SPLIT_INTERVAL_CAPABLE in the struct blk_integrity flags for ublk
devices to opt out of the integrity-interval dma_alignment limit.

Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Link: https://patch.msgid.link/20260313144701.1221652-3-kbusch@meta.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2 months agoblk-integrity: support arbitrary buffer alignment
Keith Busch [Fri, 13 Mar 2026 14:47:00 +0000 (07:47 -0700)] 
blk-integrity: support arbitrary buffer alignment

A bio segment may have partial interval block data with the rest
continuing into the next segments because direct-io data payloads only
need to align in memory to the device's DMA limits.

At the same time, the protection information may also be split in
multiple segments. The most likely way that may happen is if two
requests merge, or if we're directly using the io_uring user metadata.
The generate/verify, however, only ever accessed the first bip_vec.

Further, it may be possible to unalign the protection fields from the
user space buffer, or if there are odd additional opaque bytes in front
or in back of the protection information metadata region.

Change up the iteration to allow spanning multiple segments. This patch
is mostly a re-write of the protection information handling to allow any
arbitrary alignments, so it's probably easier to review the end result
rather than the diff.

Many controllers are not able to handle interval data composed of
multiple segments when PI is used, so this patch introduces a new
integrity limit that a low level driver can set to notify that it is
capable, default to false. The nvme driver is the first one to enable it
in this patch. Everyone else will force DMA alignment to the logical
block size as before to ensure interval data is always aligned within a
single segment.

Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Link: https://patch.msgid.link/20260313144701.1221652-2-kbusch@meta.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2 months agoblk-cgroup: wait for blkcg cleanup before initializing new disk
Ming Lei [Wed, 11 Mar 2026 03:28:37 +0000 (11:28 +0800)] 
blk-cgroup: wait for blkcg cleanup before initializing new disk

When a queue is shared across disk rebind (e.g., SCSI unbind/bind), the
previous disk's blkcg state is cleaned up asynchronously via
disk_release() -> blkcg_exit_disk(). If the new disk's blkcg_init_disk()
runs before that cleanup finishes, we may overwrite q->root_blkg while
the old one is still alive, and radix_tree_insert() in blkg_create()
fails with -EEXIST because the old blkg entries still occupy the same
queue id slot in blkcg->blkg_tree. This causes the sd probe to fail
with -ENOMEM.

Fix it by waiting in blkcg_init_disk() for root_blkg to become NULL,
which indicates the previous disk's blkcg cleanup has completed.

Fixes: 1059699f87eb ("block: move blkcg initialization/destroy into disk allocation/release handler")
Cc: Yi Zhang <yi.zhang@redhat.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/20260311032837.2368714-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2 months agoblock: clear BIO_QOS flags in blk_steal_bios()
Chaitanya Kulkarni [Thu, 26 Feb 2026 03:12:43 +0000 (19:12 -0800)] 
block: clear BIO_QOS flags in blk_steal_bios()

When a bio goes through the rq_qos infrastructure on a path's request
queue, it gets BIO_QOS_THROTTLED or BIO_QOS_MERGED flags set. These
flags indicate that rq_qos_done_bio() should be called on completion
to update rq_qos accounting.

During path failover in nvme_failover_req(), the bio's bi_bdev is
redirected from the failed path's disk to the multipath head's disk
via bio_set_dev(). However, the BIO_QOS flags are not cleared.

When the bio eventually completes (either successfully via a new path
or with an error via bio_io_error()), rq_qos_done_bio() checks for
these flags and calls __rq_qos_done_bio(q->rq_qos, bio) where q is
obtained from the bio's current bi_bdev - which is now the multipath
head's queue, not the original path's queue.

The multipath head's queue does not have rq_qos enabled (q->rq_qos is
NULL), but the code assumes that if BIO_QOS_* flags are set, q->rq_qos
must be valid.

This breaks when a bio is moved between queues during NVMe multipath
failover, leading to a NULL pointer dereference.

Execution Context timeline :-

   * =====> dd process context
   [USER] dd process
     [SYSCALL] write() - dd process context
       submit_bio()
       nvme_ns_head_submit_bio() - path selection
       blk_mq_submit_bio()  #### QOS FLAGS SET HERE

        [USER] dd waits or returns

          ==== I/O in flight on NVMe hardware =====

   ===== End of submission path ====
   ------------------------------------------------------

   * dd ====> Interrupt context;
   [IRQ] NVMe completion interrupt
       nvme_irq()
        nvme_complete_rq()
         nvme_failover_req() ### BIO MOVED TO HEAD
            spin_lock_irqsave (atomic section)
            bio_set_dev() changes bi_bdev
            ### BUG: QOS flags NOT cleared
            kblockd_schedule_work()

   * Interrupt context =====> kblockd workqueue
   [WQ] kblockd workqueue - kworker process
       nvme_requeue_work()
        submit_bio_noacct()
         nvme_ns_head_submit_bio()
          nvme_find_path() returns NULL
           bio_io_error()
            bio_endio()
             rq_qos_done_bio()  ### CRASH ###

   KERNEL PANIC / OOPS

Crash from blktests nvme/058 (rapid namespace remapping):

[ 1339.636033] BUG: kernel NULL pointer dereference, address: 0000000000000000
[ 1339.641025] nvme nvme4: rescanning namespaces.
[ 1339.642064] #PF: supervisor read access in kernel mode
[ 1339.642067] #PF: error_code(0x0000) - not-present page
[ 1339.642070] PGD 0 P4D 0
[ 1339.642073] Oops: Oops: 0000 [#1] SMP NOPTI
[ 1339.642078] CPU: 35 UID: 0 PID: 4579 Comm: kworker/35:2H
               Tainted: G   O     N  6.17.0-rc3nvme+ #5 PREEMPT(voluntary)
[ 1339.642084] Tainted: [O]=OOT_MODULE, [N]=TEST
[ 1339.673446] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
           BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[ 1339.682359] Workqueue: kblockd nvme_requeue_work [nvme_core]
[ 1339.686613] RIP: 0010:__rq_qos_done_bio+0xd/0x40
[ 1339.690161] Code: 75 dd 5b 5d 41 5c c3 cc cc cc cc 66 90 90 90 90 90 90 90
                     90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 55 48 89 f5
             53 48 89 fb <48> 8b 03 48 8b 40 30 48 85 c0 74 0b 48 89 ee
             48 89 df ff d0 0f 1f
[ 1339.703691] RSP: 0018:ffffc900066f3c90 EFLAGS: 00010202
[ 1339.706844] RAX: ffff888148b9ef00 RBX: 0000000000000000 RCX: 0000000000000000
[ 1339.711136] RDX: 00000000000001c0 RSI: ffff8882aaab8a80 RDI: 0000000000000000
[ 1339.715691] RBP: ffff8882aaab8a80 R08: 0000000000000000 R09: 0000000000000000
[ 1339.720472] R10: 0000000000000000 R11: fefefefefefefeff R12: ffff8882aa3b6010
[ 1339.724650] R13: 0000000000000000 R14: ffff8882338bcef0 R15: ffff8882aa3b6020
[ 1339.729029] FS:  0000000000000000(0000) GS:ffff88985c0cf000(0000) knlGS:0000000000000000
[ 1339.734525] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1339.738563] CR2: 0000000000000000 CR3: 0000000111045000 CR4: 0000000000350ef0
[ 1339.742750] DR0: ffffffff845ccbec DR1: ffffffff845ccbed DR2: ffffffff845ccbee
[ 1339.745630] DR3: ffffffff845ccbef DR6: 00000000ffff0ff0 DR7: 0000000000000600
[ 1339.748488] Call Trace:
[ 1339.749512]  <TASK>
[ 1339.750449]  bio_endio+0x71/0x2e0
[ 1339.751833]  nvme_ns_head_submit_bio+0x290/0x320 [nvme_core]
[ 1339.754073]  __submit_bio+0x222/0x5e0
[ 1339.755623]  ? rcu_is_watching+0xd/0x40
[ 1339.757201]  ? submit_bio_noacct_nocheck+0x131/0x370
[ 1339.759210]  submit_bio_noacct_nocheck+0x131/0x370
[ 1339.761189]  ? submit_bio_noacct+0x20/0x620
[ 1339.762849]  nvme_requeue_work+0x4b/0x60 [nvme_core]
[ 1339.764828]  process_one_work+0x20e/0x630
[ 1339.766528]  worker_thread+0x184/0x330
[ 1339.768129]  ? __pfx_worker_thread+0x10/0x10
[ 1339.769942]  kthread+0x10a/0x250
[ 1339.771263]  ? __pfx_kthread+0x10/0x10
[ 1339.772776]  ? __pfx_kthread+0x10/0x10
[ 1339.774381]  ret_from_fork+0x273/0x2e0
[ 1339.775948]  ? __pfx_kthread+0x10/0x10
[ 1339.777504]  ret_from_fork_asm+0x1a/0x30
[ 1339.779163]  </TASK>

Fix this by clearing both BIO_QOS_THROTTLED and BIO_QOS_MERGED flags
when bios are redirected to the multipath head in nvme_failover_req().
This is consistent with the existing code that clears REQ_POLLED and
REQ_NOWAIT flags when the bio changes queues.

Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/20260226031243.87200-3-kch@nvidia.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2 months agoblock: move bio queue-transition flag fixups into blk_steal_bios()
Chaitanya Kulkarni [Thu, 26 Feb 2026 03:12:42 +0000 (19:12 -0800)] 
block: move bio queue-transition flag fixups into blk_steal_bios()

blk_steal_bios() transfers bios from a request to a bio_list when the
request is requeued to a different queue. The NVMe multipath failover
path (nvme_failover_req) currently open-codes clearing of REQ_POLLED,
bi_cookie, and REQ_NOWAIT on each bio before calling blk_steal_bios().

Move these fixups into blk_steal_bios() itself so that any caller
automatically gets correct flag state when bios cross queue boundaries.
Simplify nvme_failover_req() accordingly.

Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/20260226031243.87200-2-kch@nvidia.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2 months agoMerge branch 'for-7.1/block-integrity' into for-7.1/block
Jens Axboe [Mon, 9 Mar 2026 20:30:14 +0000 (14:30 -0600)] 
Merge branch 'for-7.1/block-integrity' into for-7.1/block

Merge in integrity changes which are also landing in the VFS tree as
dependencies for fs related changes.

* for-7.1/block-integrity:
  block: pass a maxlen argument to bio_iov_iter_bounce
  block: add fs_bio_integrity helpers
  block: make max_integrity_io_size public
  block: prepare generation / verification helpers for fs usage
  block: add a bdev_has_integrity_csum helper
  block: factor out a bio_integrity_setup_default helper
  block: factor out a bio_integrity_action helper

2 months agoblock: remove bdev_nonrot()
Damien Le Moal [Thu, 26 Feb 2026 07:54:48 +0000 (16:54 +0900)] 
block: remove bdev_nonrot()

bdev_nonrot() is simply the negative return value of bdev_rot().
So replace all call sites of bdev_nonrot() with calls to bdev_rot()
and remove bdev_nonrot().

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2 months agoblock: Correct comments on bio_alloc_clone() and bio_init_clone()
John Garry [Fri, 27 Feb 2026 10:44:38 +0000 (10:44 +0000)] 
block: Correct comments on bio_alloc_clone() and bio_init_clone()

Correct the comments that the cloned bio must be freed before the memory
pointed to by @bio_src->bi_io_vecs (is freed).

Christoph Hellwig contributed most the of the update wording.

Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2 months agoDocumentation: ABI: stable: document the zoned_qd1_writes attribute
Damien Le Moal [Fri, 27 Feb 2026 13:19:51 +0000 (22:19 +0900)] 
Documentation: ABI: stable: document the zoned_qd1_writes attribute

Update the documentation file Documentation/ABI/stable/sysfs-block to
describe the zoned_qd1_writes sysfs queue attribute file.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2 months agoblock: default to QD=1 writes for blk-mq rotational zoned devices
Damien Le Moal [Fri, 27 Feb 2026 13:19:50 +0000 (22:19 +0900)] 
block: default to QD=1 writes for blk-mq rotational zoned devices

For blk-mq rotational zoned block devices (e.g. SMR HDDs), default to
having zone write plugging limit write operations to a maximum queue
depth of 1 for all zones. This significantly reduce write seek overhead
and improves SMR HDD write throughput.

For remotely connected disks with a very high network latency this
features might not be useful. However, remotely connected zoned devices
are rare at the moment, and we cannot know the round trip latency to
pick a good default for network attached devices. System administrators
can however disable this feature in that case.

For BIO based (non blk-mq) rotational zoned block devices, the device
driver (e.g. a DM target driver) can directly set an appropriate
default.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2 months agoblock: allow submitting all zone writes from a single context
Damien Le Moal [Fri, 27 Feb 2026 13:19:49 +0000 (22:19 +0900)] 
block: allow submitting all zone writes from a single context

In order to maintain sequential write patterns per zone with zoned block
devices, zone write plugging issues only a single write BIO per zone at
any time. This works well but has the side effect that when large
sequential write streams are issued by the user and these streams cross
zone boundaries, the device ends up receiving a discontiguous set of
write commands for different zones. The same also happens when a user
writes simultaneously at high queue depth multiple zones: the device
does not see all sequential writes per zone and receives discontiguous
writes to different zones. While this does not affect the performance of
solid state zoned block devices, when using an SMR HDD, this pattern
change from sequential writes to discontiguous writes to different zones
significantly increases head seek which results in degraded write
throughput.

In order to reduce this seek overhead for rotational media devices,
introduce a per disk zone write plugs kernel thread to issue all write
BIOs to zones. This single zone write issuing context is enabled for
any zoned block device that has a request queue flagged with the new
QUEUE_ZONED_QD1_WRITES flag.

The flag QUEUE_ZONED_QD1_WRITES is visible as the sysfs queue attribute
zoned_qd1_writes for zoned devices. For regular block devices, this
attribute is not visible. For zoned block devices, a user can override
the default value set to force the global write maximum queue depth of
1 for a zoned block device, or clear this attribute to fallback to the
default behavior of zone write plugging which limits writes to QD=1 per
sequential zone.

Writing to a zoned block device flagged with QUEUE_ZONED_QD1_WRITES is
implemented using a list of zone write plugs that have a non-empty BIO
list. Listed zone write plugs are processed by the disk zone write plugs
worker kthread in FIFO order, and all BIOs of a zone write plug are all
processed before switching to the next listed zone write plug. A newly
submitted BIO for a non-FULL zone write plug that is not yet listed
causes the addition of the zone write plug at the end of the disk list
of zone write plugs.

Since the write BIOs queued in a zone write plug BIO list are
necessarilly sequential, for rotational media, using the single zone
write plugs kthread to issue all BIOs maintains a sequential write
pattern and thus reduces seek overhead and improves write throughput.
This processing essentially result in always writing to HDDs at QD=1,
which is not an issue for HDDs operating with write caching enabled.
Performance with write cache disabled is also not degraded thanks to
the efficient write handling of modern SMR HDDs.

A disk list of zone write plugs is defined using the new struct gendisk
zone_wplugs_list, and accesses to this list is protected using the
zone_wplugs_list_lock spinlock.  The per disk kthread
(zone_wplugs_worker) code is implemented by the function
disk_zone_wplugs_worker(). A reference on listed zone write plugs is
always held until all BIOs of the zone write plug are processed by the
worker kthread. BIO issuing at QD=1 is driven using a completion
structure (zone_wplugs_worker_bio_done) and calls to blk_io_wait().

With this change, performance when sequentially writing the zones of a
30 TB SMR SATA HDD connected to an AHCI adapter changes as follows
(1MiB direct I/Os, results in MB/s unit):

                    +--------------------+
    |   Write BW (MB/s)  |
 +------------------+----------+---------+
 | Sequential write | Baseline | Patched |
 |  Queue Depth     | 6.19-rc8 |         |
 +------------------+----------+---------+
 | 1                | 244      | 245     |
 | 2                | 244      | 245     |
 | 4                | 245      | 245     |
 | 8                | 242      | 245     |
 | 16               | 222      | 246     |
 | 32               | 211      | 245     |
 | 64               | 193      | 244     |
 | 128              | 112      | 246     |
 +------------------+----------+---------+

With the current code (baseline), as the sequential write stream crosses
a zone boundary, higher queue depth creates a gap between the
last IO to the previous zone and the first IOs to the following zones,
causing head seeks and degrading performance. Using the disk zone
write plugs worker thread, this pattern disappears and the maximum
throughput of the drive is maintained, leading to over 100%
improvements in throughput for high queue depth write.

Using 16 fio jobs all writing to randomly chosen zones at QD=32 with 1
MiB direct IOs, write throughput also increases significantly.

                    +--------------------+
    |   Write BW (MB/s)  |
 +------------------+----------+---------+
 |   Random write   | Baseline | Patched |
 |  Number of zones | 6.19-rc7 |         |
 +------------------+----------+---------+
 | 1                | 191      | 192     |
 | 2                | 101      | 128     |
 | 4                | 115      | 123     |
 | 8                | 90       | 120     |
 | 16               | 64       | 115     |
 | 32               | 58       | 105     |
 | 64               | 56       | 101     |
 | 128              | 55       | 99      |
 +------------------+----------+---------+

Tests using XFS shows that buffered write speed with 8 jobs writing
files increases by 12% to 35% depending on the workload.

                    +--------------------+
    |   Write BW (MB/s)  |
 +------------------+----------+---------+
 |     Workload     | Baseline | Patched |
 |                  | 6.19-rc7 |         |
 +------------------+----------+---------+
 | 256MiB file size | 212      | 238     |
 +------------------+----------+---------+
 | 4MiB .. 128 MiB  | 213      | 243     |
 | random file size |          |         |
 +------------------+----------+---------+
 | 2MiB .. 8 MiB    | 179      | 242     |
 | random file size |          |         |
 +------------------+----------+---------+

Performance gains are even more significant when using an HBA that
limits the maximum size of commands to a small value, e.g. HBAs
controlled with the mpi3mr driver limit commands to a maximum of 1 MiB.
In such case, the write throughput gains are over 40%.

                    +--------------------+
    |   Write BW (MB/s)  |
 +------------------+----------+---------+
 |     Workload     | Baseline | Patched |
 |                  | 6.19-rc7 |         |
 +------------------+----------+---------+
 | 256MiB file size | 175      | 245     |
 +------------------+----------+---------+
 | 4MiB .. 128 MiB  | 174      | 244     |
 | random file size |          |         |
 +------------------+----------+---------+
 | 2MiB .. 8 MiB    | 171      | 243     |
 | random file size |          |         |
 +------------------+----------+---------+

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>