8 Commits

Author SHA1 Message Date
Keith Busch
3850e13f28 block: export dma_alignment attribute
User space may want to know how to align their buffers to avoid
bouncing. Export the queue attribute.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220610195830.3574005-4-kbusch@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-06-27 06:29:11 -06:00
Eric Biggers
20f01f1632 blk-crypto: show crypto capabilities in sysfs
Add sysfs files that expose the inline encryption capabilities of
request queues:

	/sys/block/$disk/queue/crypto/max_dun_bits
	/sys/block/$disk/queue/crypto/modes/$mode
	/sys/block/$disk/queue/crypto/num_keyslots

Userspace can use these new files to decide what encryption settings to
use, or whether to use inline encryption at all.  This also brings the
crypto capabilities in line with the other queue properties, which are
already discoverable via the queue directory in sysfs.

Design notes:

  - Place the new files in a new subdirectory "crypto" to group them
    together and to avoid complicating the main "queue" directory.  This
    also makes it possible to replace "crypto" with a symlink later if
    we ever make the blk_crypto_profiles into real kobjects (see below).

  - It was necessary to define a new kobject that corresponds to the
    crypto subdirectory.  For now, this kobject just contains a pointer
    to the blk_crypto_profile.  Note that multiple queues (and hence
    multiple such kobjects) may refer to the same blk_crypto_profile.

    An alternative design would more closely match the current kernel
    data structures: the blk_crypto_profile could be a kobject itself,
    located directly under the host controller device's kobject, while
    /sys/block/$disk/queue/crypto would be a symlink to it.

    I decided not to do that for now because it would require a lot more
    changes, such as no longer embedding blk_crypto_profile in other
    structures, and also because I'm not sure we can rule out moving the
    crypto capabilities into 'struct queue_limits' in the future.  (Even
    if multiple queues share the same crypto engine, maybe the supported
    data unit sizes could differ due to other queue properties.)  It
    would also still be possible to switch to that design later without
    breaking userspace, by replacing the directory with a symlink.

  - Use "max_dun_bits" instead of "max_dun_bytes".  Currently, the
    kernel internally stores this value in bytes, but that's an
    implementation detail.  It probably makes more sense to talk about
    this value in bits, and choosing bits is more future-proof.

  - "modes" is a sub-subdirectory, since there may be multiple supported
    crypto modes, sysfs is supposed to have one value per file, and it
    makes sense to group all the mode files together.

  - Each mode had to be named.  The crypto API names like "xts(aes)" are
    not appropriate because they don't specify the key size.  Therefore,
    I assigned new names.  The exact names chosen are arbitrary, but
    they happen to match the names used in log messages in fs/crypto/.

  - The "num_keyslots" file is a bit different from the others in that
    it is only useful to know for performance reasons.  However, it's
    included as it can still be useful.  For example, a user might not
    want to use inline encryption if there aren't very many keyslots.

Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20220124215938.2769-4-ebiggers@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-02-28 06:40:23 -07:00
Eric Biggers
8bc2f7c670 docs: sysfs-block: document virt_boundary_mask
/sys/block/<disk>/queue/virt_boundary_mask is completely undocumented.
Document it.

Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20211209003833.6396-7-ebiggers@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-01-09 18:59:10 -07:00
Eric Biggers
1163010418 docs: sysfs-block: document stable_writes
/sys/block/<disk>/queue/stable_writes is completely undocumented.
Document it.

Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20211209003833.6396-6-ebiggers@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-01-09 18:59:10 -07:00
Eric Biggers
849ab826e1 docs: sysfs-block: fill in missing documentation from queue-sysfs.rst
sysfs documentation is supposed to go in Documentation/ABI/.
However, /sys/block/<disk>/queue/* are documented in
Documentation/block/queue-sysfs.rst, and sometimes redundantly in
Documentation/ABI/stable/sysfs-block too.

Let's consolidate this documentation into Documentation/ABI/.

Therefore, copy the relevant docs from queue-sysfs.rst into sysfs-block.

This primarily means adding the 25 missing files that were documented in
queue-sysfs.rst only, as well as mentioning the RO/RW status of files.

Documentation/ABI/ requires "Date" and "Contact" fields.  For the Date
fields, I used the date of the commit which added support for each file.
For the "Contact" fields, I used linux-block.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20211209003833.6396-5-ebiggers@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-01-09 18:59:10 -07:00
Eric Biggers
8b0551a74b docs: sysfs-block: add contact for nomerges
The nomerges file was missing a "Contact" entry.  Use linux-block.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20211209003833.6396-4-ebiggers@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-01-09 18:59:10 -07:00
Eric Biggers
07c9093c42 docs: sysfs-block: sort alphabetically
Sort the documentation for the files alphabetically by file path so that
there is a logical order and it's clear where to add new files.

With two small exceptions, this patch doesn't change the documentation
itself and just reorders it:

- In /sys/block/<disk>/<part>/stat, I replaced <part> with <partition>
  to be consistent with the other files.
- The description for /sys/block/<disk>/<part>/stat referred to another
  file "above", which I reworded.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20211209003833.6396-3-ebiggers@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-01-09 18:59:10 -07:00
Eric Biggers
ae7a7a5349 docs: sysfs-block: move to stable directory
The block layer sysfs ABI is widely used by userspace software and is
considered stable.

Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20211209003833.6396-2-ebiggers@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-01-09 18:59:10 -07:00