linux-stable.git/include/uapi/linux/ublk_cmd.h, branch v6.15.2

ublk: add segment parameter

2025-03-28T22:15:43+00:00

IO split is usually bad in io_uring world, since -EAGAIN is caused and
IO handling may have to fallback to io-wq, this way does hurt performance.

ublk starts to support zero copy recently, for avoiding unnecessary IO
split, ublk driver's segment limit should be aligned with backend
device's segment limit.

Another reason is that io_buffer_register_bvec() needs to allocate bvecs,
which number is aligned with ublk request segment number, so that big
memory allocation can be avoided by setting reasonable max_segments limit.

So add segment parameter for providing ublk server chance to align
segment limit with backend, and keep it reasonable from implementation
viewpoint.

Signed-off-by: Ming Lei 
Link: https://lore.kernel.org/r/20250327095123.179113-7-ming.lei@redhat.com
Signed-off-by: Jens Axboe

Merge tag 'for-6.15/block-20250322' of git://git.kernel.dk/linux

2025-03-27T01:08:55+00:00

Pull block updates from Jens Axboe:

 - Fixes for integrity handling

 - NVMe pull request via Keith:
      - Secure concatenation for TCP transport (Hannes)
      - Multipath sysfs visibility (Nilay)
      - Various cleanups (Qasim, Baruch, Wang, Chen, Mike, Damien, Li)
      - Correct use of 64-bit BARs for pci-epf target (Niklas)
      - Socket fix for selinux when used in containers (Peijie)

 - MD pull request via Yu:
      - fix recovery can preempt resync (Li Nan)
      - fix md-bitmap IO limit (Su Yue)
      - fix raid10 discard with REQ_NOWAIT (Xiao Ni)
      - fix raid1 memory leak (Zheng Qixing)
      - fix mddev uaf (Yu Kuai)
      - fix raid1,raid10 IO flags (Yu Kuai)
      - some refactor and cleanup (Yu Kuai)

 - Series cleaning up and fixing bugs in the bad block handling code

 - Improve support for write failure simulation in null_blk

 - Various lock ordering fixes

 - Fixes for locking for debugfs attributes

 - Various ublk related fixes and improvements

 - Cleanups for blk-rq-qos wait handling

 - blk-throttle fixes

 - Fixes for loop dio and sync handling

 - Fixes and cleanups for the auto-PI code

 - Block side support for hardware encryption keys in blk-crypto

 - Various cleanups and fixes

* tag 'for-6.15/block-20250322' of git://git.kernel.dk/linux: (105 commits)
  nvmet: replace max(a, min(b, c)) by clamp(val, lo, hi)
  nvme-tcp: fix selinux denied when calling sock_sendmsg
  nvmet: pci-epf: Always configure BAR0 as 64-bit
  nvmet: Remove duplicate uuid_copy
  nvme: zns: Simplify nvme_zone_parse_entry()
  nvmet: pci-epf: Remove redundant 'flush_workqueue()' calls
  nvmet-fc: Remove unused functions
  nvme-pci: remove stale comment
  nvme-fc: Utilise min3() to simplify queue count calculation
  nvme-multipath: Add visibility for queue-depth io-policy
  nvme-multipath: Add visibility for numa io-policy
  nvme-multipath: Add visibility for round-robin io-policy
  nvmet: add tls_concat and tls_key debugfs entries
  nvmet-tcp: support secure channel concatenation
  nvmet: Add 'sq' argument to alloc_ctrl_args
  nvme-fabrics: reset admin connection for secure concatenation
  nvme-tcp: request secure channel concatenation
  nvme-keyring: add nvme_tls_psk_refresh()
  nvme: add nvme_auth_derive_tls_psk()
  nvme: add nvme_auth_generate_digest()
  ...

ublk: add DMA alignment limit

2025-03-03T18:17:52+00:00

The in-tree ublk driver doesn't need DMA alignment limit because there
is one data copy between request pages and the userspace buffer.

However, ublk is going to support zero copy, then DMA alignment limit
is required, because same IO buffer is forwarded to backend which may
have specific buffer DMA alignment limit, so the limit has to be exposed
from the frontend driver to client application.

Cc: Keith Busch 
Signed-off-by: Ming Lei 
Link: https://lore.kernel.org/r/20250227103707.2640014-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe

ublk: zc register/unregister bvec

2025-02-28T14:05:41+00:00

Provide new operations for the user to request mapping an active request
to an io uring instance's buf_table. The user has to provide the index
it wants to install the buffer.

A reference count is taken on the request to ensure it can't be
completed while it is active in a ring's buf_table.

Signed-off-by: Keith Busch 
Link: https://lore.kernel.org/r/20250227223916.143006-6-kbusch@meta.com
Reviewed-by: Ming Lei 
Signed-off-by: Jens Axboe

ublk: support device recovery without I/O queueing

2024-10-22T14:16:37+00:00

ublk currently supports the following behaviors on ublk server exit:

A: outstanding I/Os get errors, subsequently issued I/Os get errors
B: outstanding I/Os get errors, subsequently issued I/Os queue
C: outstanding I/Os get reissued, subsequently issued I/Os queue

and the following behaviors for recovery of preexisting block devices by
a future incarnation of the ublk server:

1: ublk devices stopped on ublk server exit (no recovery possible)
2: ublk devices are recoverable using start/end_recovery commands

The userspace interface allows selection of combinations of these
behaviors using flags specified at device creation time, namely:

default behavior: A + 1
UBLK_F_USER_RECOVERY: B + 2
UBLK_F_USER_RECOVERY|UBLK_F_USER_RECOVERY_REISSUE: C + 2

The behavior A + 2 is currently unsupported. Add support for this
behavior under the new flag combination
UBLK_F_USER_RECOVERY|UBLK_F_USER_RECOVERY_FAIL_IO.

Signed-off-by: Uday Shankar 
Reviewed-by: Ming Lei 
Link: https://lore.kernel.org/r/20241007182419.3263186-5-ushankar@purestorage.com
Signed-off-by: Jens Axboe

ublk: don't allow user copy for unprivileged device

2024-10-16T14:08:18+00:00

UBLK_F_USER_COPY requires userspace to call write() on ublk char
device for filling request buffer, and unprivileged device can't
be trusted.

So don't allow user copy for unprivileged device.

Cc: stable@vger.kernel.org
Fixes: 1172d5b8beca ("ublk: support user copy")
Signed-off-by: Ming Lei 
Link: https://lore.kernel.org/r/20241016134847.2911721-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe

ublk: add UBLK_CMD_DEL_DEV_ASYNC

2024-02-29T01:47:08+00:00

The current command UBLK_CMD_DEL_DEV won't return until the device is
released, this way looks more reliable, but makes userspace more
difficult to implement, especially about orders: unmap command
buffer(which holds one ublkc reference), ublkc close,
io_uring_file_unregister, ublkb close.

Add UBLK_CMD_DEL_DEV_ASYNC so that device deletion won't wait release,
then userspace needn't worry about the above order. Actually both loop
and nbd is deleted in this async way.

Signed-off-by: Ming Lei 
Link: https://lore.kernel.org/r/20240223075539.89945-3-ming.lei@redhat.com
Signed-off-by: Jens Axboe

ublk: zoned: support REQ_OP_ZONE_RESET_ALL

2023-08-21T02:24:34+00:00

There isn't any reason to not support REQ_OP_ZONE_RESET_ALL given everything
is actually handled in userspace, not mention it is pretty easy to support
RESET_ALL.

So enable REQ_OP_ZONE_RESET_ALL and let userspace handle it.

Verified by 'tools/zbc_reset_zone -all /dev/ublkb0' in libzbc[1] with
libublk-rs based ublk-zoned target prototype[2], follows command line
for creating ublk-zoned:

	cargo run --example zoned -- add -1 1024	# add $dev_id $DEV_SIZE

[1] https://github.com/westerndigitalcorporation/libzbc
[2] https://github.com/ming1/libublk-rs/tree/zoned.v2

Cc: Niklas Cassel 
Cc: Damien Le Moal 
Cc: Andreas Hindborg 
Signed-off-by: Ming Lei 
Link: https://lore.kernel.org/r/20230810124326.321472-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe

ublk: enable zoned storage support

2023-08-08T21:45:53+00:00

Add zoned storage support to ublk: report_zones and operations:
 - REQ_OP_ZONE_OPEN
 - REQ_OP_ZONE_CLOSE
 - REQ_OP_ZONE_FINISH
 - REQ_OP_ZONE_RESET
 - REQ_OP_ZONE_APPEND

The zone append feature uses the `addr` field of `struct ublksrv_io_cmd` to
communicate ALBA back to the kernel. Therefore ublk must be used with the
user copy feature (UBLK_F_USER_COPY) for zoned storage support to be
available. Without this feature, ublk will not allow zoned storage support.

Signed-off-by: Andreas Hindborg 
Reviewed-by: Ming Lei 
Tested-by: Ming Lei 
Link: https://lore.kernel.org/r/20230804114610.179530-4-nmi@metaspace.dk
Signed-off-by: Jens Axboe

ublk: add control command of UBLK_U_CMD_GET_FEATURES

2023-06-04T14:34:14+00:00

Add control command of UBLK_U_CMD_GET_FEATURES for returning driver's
feature set or capability.

This way can simplify userspace for maintaining compatibility because
userspace doesn't need to send command to one device for querying driver
feature set any more. Such as, with the queried feature set, userspace
can choose to use:

- UBLK_CMD_GET_DEV_INFO2 or UBLK_CMD_GET_DEV_INFO,
- UBLK_U_CMD_* or UBLK_CMD_*

Userspace code:
	https://github.com/ming1/ubdsrv/commits/features-cmd

Signed-off-by: Ming Lei 
Link: https://lore.kernel.org/r/20230603040601.775227-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe