254 Commits
Author SHA1 Message Date
Ming LeiandJens Axboe 289653bb76 Documentation: ublk: address review comments for SHMEM_ZC docs
- Use "physical pages" instead of "page frame numbers (PFNs)" for
  clarity
- Remove "without any per-I/O overhead" claim from zero-copy
  description
- Add scatter/gather limitation: each I/O's data must be contiguous
  within a single registered buffer

Suggested-by: Caleb Sander Mateos <csander@purestorage.com>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Link: https://patch.msgid.link/20260409133020.3780098-7-tom.leiming@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-04-09 19:10:44 -06:00
Ming LeiandJens Axboe 08677040a9 ublk: enable UBLK_F_SHMEM_ZC feature flag
Add UBLK_F_SHMEM_ZC (1ULL << 19) to the UAPI header and UBLK_F_ALL.
Switch ublk_support_shmem_zc() and ublk_dev_support_shmem_zc() from
returning false to checking the actual flag, enabling the shared
memory zero-copy feature for devices that request it.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://patch.msgid.link/20260331153207.3635125-4-ming.lei@redhat.com
[axboe: ublk_buf_reg -> ublk_shmem_buf_reg errors]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-04-07 07:39:24 -06:00
Christoph HellwigandJens Axboe 4e56428ed4 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>
2026-04-02 07:09:03 -06:00
Keith BuschandJens Axboe 72a41750f1 block: remove bio_last_bvec_all
There are no more callers of this function after commit f6b2d8b134
("btrfs: track the next file offset in struct btrfs_bio_ctrl"), so
remove the function.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Kanchan Joshi <joshi.k@samsung.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-01-26 21:07:48 -07:00
Ming LeiandJens Axboe 4d8fd7c559 ublk: document feature UBLK_F_BATCH_IO
Document feature UBLK_F_BATCH_IO.

Reviewed-by: Caleb Sander Mateos <csander@purestorage.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-01-22 20:05:40 -07:00
Christoph HellwigandJens Axboe bb8e2019ad blk-crypto: handle the fallback above the block layer
Add a blk_crypto_submit_bio helper that either submits the bio when
it is not encrypted or inline encryption is provided, but otherwise
handles the encryption before going down into the low-level driver.
This reduces the risk from bio reordering and keeps memory allocation
as high up in the stack as possible.

Note that if the submitter knows that inline enctryption is known to
be supported by the underyling driver, it can still use plain
submit_bio.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2026-01-11 12:55:41 -07:00
Bagas SanjayaandJens Axboe db3dfae1a2 Documentation: ublk: Separate UBLK_F_AUTO_BUF_REG fallback behavior sublists
Stephen Rothwell reports htmldocs warning on ublk docs:

Documentation/block/ublk.rst:414: ERROR: Unexpected indentation. [docutils]

Fix the warning by separating sublists of auto buffer registration
fallback behavior from their appropriate parent list item.

Fixes: ff20c51648 ("ublk: document auto buffer registration(UBLK_F_AUTO_BUF_REG)")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Closes: https://lore.kernel.org/linux-next/20250612132638.193de386@canb.auug.org.au/
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Link: https://lore.kernel.org/r/20250613023857.15971-1-bagasdotme@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-06-13 09:25:42 -06:00
Ming LeiandJens Axboe ff20c51648 ublk: document auto buffer registration(UBLK_F_AUTO_BUF_REG)
Document recently merged feature auto buffer registration(UBLK_F_AUTO_BUF_REG).

Cc: Caleb Sander Mateos <csander@purestorage.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20250611085632.109719-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-06-11 06:41:55 -06:00
Uday ShankarandJens Axboe 08652bd86e Documentation: ublk: document UBLK_F_PER_IO_DAEMON
Explain the restrictions imposed on ublk servers in two cases:
1. When UBLK_F_PER_IO_DAEMON is set (current ublk_drv)
2. When UBLK_F_PER_IO_DAEMON is not set (legacy)

Remove most references to per-queue daemons, as the new
UBLK_F_PER_IO_DAEMON feature renders that concept obsolete.

Signed-off-by: Uday Shankar <ushankar@purestorage.com>
Reviewed-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20250529-ublk_task_per_io-v8-9-e9d3b119336a@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-05-31 14:38:57 -06:00
Jens Axboe f28a71bc97 Documentation: ublk: remove dead footnote
A previous commit removed the use of this footnote, delete it.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Fixes: 3fdf2ec7da ("Documentation: ublk: Drop Stefan Hajnoczi's message footnote")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-03-31 07:06:22 -06:00
Ming LeiandJens Axboe 1797020916 ublk: document zero copy feature
Add words to explain how zero copy feature works, and why it has to be
trusted for handling IO read command.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20250327095123.179113-8-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-03-28 16:15:43 -06:00
Eric BiggersandJens Axboe 1ebd4a3c09 blk-crypto: add ioctls to create and prepare hardware-wrapped keys
Until this point, the kernel can use hardware-wrapped keys to do
encryption if userspace provides one -- specifically a key in
ephemerally-wrapped form.  However, no generic way has been provided for
userspace to get such a key in the first place.

Getting such a key is a two-step process.  First, the key needs to be
imported from a raw key or generated by the hardware, producing a key in
long-term wrapped form.  This happens once in the whole lifetime of the
key.  Second, the long-term wrapped key needs to be converted into
ephemerally-wrapped form.  This happens each time the key is "unlocked".

In Android, these operations are supported in a generic way through
KeyMint, a userspace abstraction layer.  However, that method is
Android-specific and can't be used on other Linux systems, may rely on
proprietary libraries, and also misleads people into supporting KeyMint
features like rollback resistance that make sense for other KeyMint keys
but don't make sense for hardware-wrapped inline encryption keys.

Therefore, this patch provides a generic kernel interface for these
operations by introducing new block device ioctls:

- BLKCRYPTOIMPORTKEY: convert a raw key to long-term wrapped form.

- BLKCRYPTOGENERATEKEY: have the hardware generate a new key, then
  return it in long-term wrapped form.

- BLKCRYPTOPREPAREKEY: convert a key from long-term wrapped form to
  ephemerally-wrapped form.

These ioctls are implemented using new operations in blk_crypto_ll_ops.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Tested-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org> # sm8650
Link: https://lore.kernel.org/r/20250204060041.409950-4-ebiggers@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-02-10 09:54:19 -07:00
Eric BiggersandJens Axboe ebc4176551 blk-crypto: add basic hardware-wrapped key support
To prevent keys from being compromised if an attacker acquires read
access to kernel memory, some inline encryption hardware can accept keys
which are wrapped by a per-boot hardware-internal key.  This avoids
needing to keep the raw keys in kernel memory, without limiting the
number of keys that can be used.  Such hardware also supports deriving a
"software secret" for cryptographic tasks that can't be handled by
inline encryption; this is needed for fscrypt to work properly.

To support this hardware, allow struct blk_crypto_key to represent a
hardware-wrapped key as an alternative to a raw key, and make drivers
set flags in struct blk_crypto_profile to indicate which types of keys
they support.  Also add the ->derive_sw_secret() low-level operation,
which drivers supporting wrapped keys must implement.

For more information, see the detailed documentation which this patch
adds to Documentation/block/inline-encryption.rst.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Tested-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org> # sm8650
Link: https://lore.kernel.org/r/20250204060041.409950-2-ebiggers@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-02-10 09:54:19 -07:00
Bagas SanjayaandJonathan Corbet 3fdf2ec7da Documentation: ublk: Drop Stefan Hajnoczi's message footnote
Sphinx reports unreferenced footnote warning pointing to ubd-control
message by Stefan Hajnoczi:

Documentation/block/ublk.rst:336: WARNING: Footnote [#] is not referenced. [ref.footnote]

Drop the footnote to squash above warning.

Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Fixes: 4093cb5a06 ("ublk_drv: add mechanism for supporting unprivileged ublk device")
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250122143456.68867-3-bagasdotme@gmail.com
2025-01-28 15:02:17 -07:00
Uday ShankarandJens Axboe 69f407ee8d Documentation: ublk: document UBLK_F_USER_RECOVERY_FAIL_IO
Signed-off-by: Uday Shankar <ushankar@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20241007182419.3263186-6-ushankar@purestorage.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-10-22 08:16:40 -06:00
Christian MarangiandJens Axboe 592e4deeab docs: block: Document support for read-only partition in cmdline part
Document support for read-only partition in cmdline partition for block
devices by appending "ro" after the (partition name).

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Link: https://lore.kernel.org/r/20241002221306.4403-3-ansuelsmth@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-10-22 08:14:56 -06:00
Karol PrzybylskiandJonathan Corbet 2259b06938 docs: block: Fix grammar and spelling mistakes in bfq-iosched.rst
This patch corrects several grammar and spelling errors in the
Documentation/block/bfq-iosched.rst file. These changes improve
the clarity and readability of the documentation.

Signed-off-by: Karol Przybylski <karprzy7@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240814155558.3672833-1-karprzy7@gmail.com
2024-09-05 14:38:10 -06:00
Christoph HellwigandJens Axboe 4e54ea72ed block: fix spelling and grammar for in writeback_cache_control.rst
Suggested-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20240619154623.450048-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-06-20 06:53:14 -06:00
Christoph HellwigandJens Axboe 1122c0c1cc block: move cache control settings out of queue->flags
Move the cache control settings into the queue_limits so that the flags
can be set atomically with the device queue frozen.

Add new features and flags field for the driver set flags, and internal
(usually sysfs-controlled) flags in the block layer.  Note that we'll
eventually remove enough field from queue_limits to bring it back to the
previous size.

The disable flag is inverted compared to the previous meaning, which
means it now survives a rescan, similar to the max_sectors and
max_discard_sectors user limits.

The FLUSH and FUA flags are now inherited by blk_stack_limits, which
simplified the code in dm a lot, but also causes a slight behavior
change in that dm-switch and dm-unstripe now advertise a write cache
despite setting num_flush_bios to 0.  The I/O path will handle this
gracefully, but as far as I can tell the lack of num_flush_bios
and thus flush support is a pre-existing data integrity bug in those
targets that really needs fixing, after which a non-zero num_flush_bios
should be required in dm for targets that map to underlying devices.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://lore.kernel.org/r/20240617060532.127975-14-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-06-19 07:58:28 -06:00
Christoph HellwigandJens Axboe c6e56cf6b2 block: move integrity information into queue_limits
Move the integrity information into the queue limits so that it can be
set atomically with other queue limits, and that the sysfs changes to
the read_verify and write_generate flags are properly synchronized.
This also allows to provide a more useful helper to stack the integrity
fields, although it still is separate from the main stacking function
as not all stackable devices want to inherit the integrity settings.
Even with that it greatly simplifies the code in md and dm.

Note that the integrity field is moved as-is into the queue limits.
While there are good arguments for removing the separate blk_integrity
structure, this would cause a lot of churn and might better be done at a
later time if desired.  However the integrity field in the queue_limits
structure is now unconditional so that various ifdefs can be avoided or
replaced with IS_ENABLED().  Given that tiny size of it that seems like
a worthwhile trade off.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20240613084839.1044015-13-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-06-14 10:20:07 -06:00
Christian LoehleandJens Axboe b2e792ae88 Documentation: block: ioprio: Update schedulers
This doc hasn't been touched in a while, in the meantime some
new io schedulers were added (e.g. all of mq), some with ioprio
support.

Also reword the introduction to remove reference to CFQ and the
limitation that io priorities only work on reads, which is no longer
true.

Signed-off-by: Christian Loehle <christian.loehle@arm.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/a86cfdc8-016f-40f1-8b58-0cb15d2a792c@arm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-01-18 08:21:14 -07:00
Linus Torvalds babe393974 Merge tag 'docs-6.7' of git://git.lwn.net/linux
Pull documentation updates from Jonathan Corbet:
 "The number of commits for documentation is not huge this time around,
  but there are some significant changes nonetheless:

   - Some more Spanish-language and Chinese translations

   - The much-discussed documentation of the confidential-computing
     threat model

   - Powerpc and RISCV documentation move under Documentation/arch -
     these complete this particular bit of documentation churn

   - A large traditional-Chinese documentation update

   - A new document on backporting and conflict resolution

   - Some kernel-doc and Sphinx fixes

  Plus the usual smattering of smaller updates and typo fixes"

* tag 'docs-6.7' of git://git.lwn.net/linux: (40 commits)
  scripts/kernel-doc: Fix the regex for matching -Werror flag
  docs: backporting: address feedback
  Documentation: driver-api: pps: Update PPS generator documentation
  speakup: Document USB support
  doc: blk-ioprio: Bring the doc in line with the implementation
  docs: usb: fix reference to nonexistent file in UVC Gadget
  docs: doc-guide: mention 'make refcheckdocs'
  Documentation: fix typo in dynamic-debug howto
  scripts/kernel-doc: match -Werror flag strictly
  Documentation/sphinx: Remove the repeated word "the" in comments.
  docs: sparse: add SPDX-License-Identifier
  docs/zh_CN: Add subsystem-apis Chinese translation
  docs/zh_TW: update contents for zh_TW
  docs: submitting-patches: encourage direct notifications to commenters
  docs: add backporting and conflict resolution document
  docs: move riscv under arch
  docs: update link to powerpc/vmemmap_dedup.rst
  mm/memory-hotplug: fix typo in documentation
  docs: move powerpc under arch
  PCI: Update the devres documentation regarding to pcim_*()
  ...
2023-11-01 17:11:41 -10:00
Kuan-Wei ChiuandJonathan Corbet 41bd33df4e docs: block: blk-mq.rst: correct places -> place
Corrected a typo in the blk-mq.rst documentation where 'places' was
incorrectly used instead of 'place'.

Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20230902164121.2653109-1-visitorckw@gmail.com>
2023-09-22 05:30:21 -06:00
Ard Biesheuvel 944834901a Documentation: Drop or replace remaining mentions of IA64
Drop or update mentions of IA64, as appropriate.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2023-09-11 08:13:18 +00:00
Linus Torvalds cd99b9eb4b Merge tag 'docs-6.6' of git://git.lwn.net/linux
Pull documentation updates from Jonathan Corbet:
 "Documentation work keeps chugging along; this includes:

   - Work from Carlos Bilbao to integrate rustdoc output into the
     generated HTML documentation. This took some work to figure out how
     to do it without slowing the docs build and without creating people
     who don't have Rust installed, but Carlos got there

   - Move the loongarch and mips architecture documentation under
     Documentation/arch/

   - Some more maintainer documentation from Jakub

  ... plus the usual assortment of updates, translations, and fixes"

* tag 'docs-6.6' of git://git.lwn.net/linux: (56 commits)
  Docu: genericirq.rst: fix irq-example
  input: docs: pxrc: remove reference to phoenix-sim
  Documentation: serial-console: Fix literal block marker
  docs/mm: remove references to hmm_mirror ops and clean typos
  docs/zh_CN: correct regi_chg(),regi_add() to region_chg(),region_add()
  Documentation: Fix typos
  Documentation/ABI: Fix typos
  scripts: kernel-doc: fix macro handling in enums
  scripts: kernel-doc: parse DEFINE_DMA_UNMAP_[ADDR|LEN]
  Documentation: riscv: Update boot image header since EFI stub is supported
  Documentation: riscv: Add early boot document
  Documentation: arm: Add bootargs to the table of added DT parameters
  docs: kernel-parameters: Refer to the correct bitmap function
  doc: update params of memhp_default_state=
  docs: Add book to process/kernel-docs.rst
  docs: sparse: fix invalid link addresses
  docs: vfs: clean up after the iterate() removal
  docs: Add a section on surveys to the researcher guidelines
  docs: move mips under arch
  docs: move loongarch under arch
  ...
2023-08-30 20:05:42 -07:00