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* block: save user max_sectors limitKeith Busch2023-01-291-1/+2
| | | | | | | | | | | | | | | | | The user can set the max_sectors limit to any valid value via sysfs /sys/block/<dev>/queue/max_sectors_kb attribute. If the device limits are ever rescanned, though, the limit reverts back to the potentially artificially low BLK_DEF_MAX_SECTORS value. Preserve the user's setting as the max_sectors limit as long as it's valid. The user can reset back to defaults by writing 0 to the sysfs file. Signed-off-by: Keith Busch <kbusch@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Link: https://lore.kernel.org/r/20230105205146.3610282-3-kbusch@meta.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: export dma_alignment attributeKeith Busch2022-06-271-0/+9
| | | | | | | | | | | 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>
* blk-crypto: show crypto capabilities in sysfsEric Biggers2022-02-281-0/+49
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* docs: sysfs-block: document virt_boundary_maskEric Biggers2022-01-091-0/+12
| | | | | | | | | | /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>
* docs: sysfs-block: document stable_writesEric Biggers2022-01-091-0/+17
| | | | | | | | | | /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>
* docs: sysfs-block: fill in missing documentation from queue-sysfs.rstEric Biggers2022-01-091-101/+381
| | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* docs: sysfs-block: add contact for nomergesEric Biggers2022-01-091-1/+1
| | | | | | | | | | | | 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>
* docs: sysfs-block: sort alphabeticallyEric Biggers2022-01-091-182/+203
| | | | | | | | | | | | | | | | | | | | | 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>
* docs: sysfs-block: move to stable directoryEric Biggers2022-01-091-0/+346
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>