Changes in sysfs-block

fd0ad5e9 - docs: ABI: replace mcroce@microsoft.com with new Meta address

Mon, 14 Apr 2025 07:35:31 +0000

docs: ABI: replace mcroce@microsoft.com with new Meta addressThe Microsoft email address is bouncing: 550 5.4.1 Recipient address rejected: Access denied.So let's replace it with Matteo's current mail address.Link: https://lkml.kernel.org/r/20250414-fix-mcroce-mail-bounce-v3-1-0aed2d71f3d7@pengutronix.deSigned-off-by: Ahmad Fatoum Acked-by: Matteo Croce Link: https://lore.kernel.org/all/BYAPR15MB2504E4B02DFFB1E55871955DA1062@BYAPR15MB2504.namprd15.prod.outlook.com/Cc: Daniel Lezcano Cc: Jens Axboe Cc: Matteo Croce Cc: Sascha Hauer Signed-off-by: Andrew Morton List of files: /linux-6.15/Documentation/ABI/stable/sysfs-block

fc22b34e - docs: sysfs-block: Clarify integrity sysfs attributes

Tue, 18 Mar 2025 15:44:47 +0000

docs: sysfs-block: Clarify integrity sysfs attributesThe /sys/block//integrity fields are historically setif T10 protection Information is enabled.It is not set if some upper layer uses integrity metadata.Document it.Signed-off-by: Milan Broz Co-developed-by: Martin K. Petersen Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20250318154447.370786-1-gmazyland@gmail.comSigned-off-by: Jens Axboe List of files: /linux-6.15/Documentation/ABI/stable/sysfs-block

e35fde43 - blk-crypto: show supported key types in sysfs

Tue, 04 Feb 2025 06:00:36 +0000

blk-crypto: show supported key types in sysfsAdd sysfs files that indicate which type(s) of keys are supported by theinline encryption hardware associated with a particular request queue: /sys/block/$disk/queue/crypto/hw_wrapped_keys /sys/block/$disk/queue/crypto/raw_keysUserspace can use the presence or absence of these files to decide whatencyption settings to use.Don't use a single key_type file, as devices might support both keytypes at the same time.Signed-off-by: Eric Biggers Tested-by: Bartosz Golaszewski # sm8650Link: https://lore.kernel.org/r/20250204060041.409950-3-ebiggers@kernel.orgSigned-off-by: Jens Axboe List of files: /linux-6.15/Documentation/ABI/stable/sysfs-block

0740e543 - mm, doc: update read_ahead_kb for MADV_HUGEPAGE

Wed, 13 Nov 2024 15:07:11 +0000

mm, doc: update read_ahead_kb for MADV_HUGEPAGEMADV_HUGEPAGE is a new addition to readahead with behavior distinct fromnormal pages. To prevent confusion, we should update the documentationaccordingly.Link: https://lkml.kernel.org/r/20241113150711.1685-1-laoar.shao@gmail.comSigned-off-by: Yafang Shao Cc: David Hildenbrand Cc: Matthew Wilcox Signed-off-by: Andrew Morton List of files: /linux-6.15/Documentation/ABI/stable/sysfs-block

110234da - block: enable passthrough command statistics

Mon, 07 Oct 2024 15:32:35 +0000

block: enable passthrough command statisticsApplications using the passthrough interfaces for IO want to continueseeing the disk stats. These requests had been fenced off from thisblock layer feature. While the block layer doesn't necessarily know whata passthrough command does, we do know the data size and direction,which is enough to account for the command's stats.Since tracking these has the potential to produce unexpected results,the passthrough stats are locked behind a new queue flag that needs tobe enabled with the /sys/block//queue/iostats_passthroughattribute.Signed-off-by: Keith Busch Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20241007153236.2818562-1-kbusch@meta.comSigned-off-by: Jens Axboe List of files: /linux-6.15/Documentation/ABI/stable/sysfs-block

9da3d1e9 - block: Add core atomic write support

Thu, 20 Jun 2024 12:53:54 +0000

block: Add core atomic write supportAdd atomic write support, as follows:- add helper functions to get request_queue atomic write limits- report request_queue atomic write support limits to sysfs and update Doc- support to safely merge atomic writes- deal with splitting atomic writes- misc helper functions- add a per-request atomic write flagNew request_queue limits are added, as follows:- atomic_write_hw_max is set by the block driver and is the maximum length of an atomic write which the device may support. It is not necessarily a power-of-2.- atomic_write_max_sectors is derived from atomic_write_hw_max_sectors and max_hw_sectors. It is always a power-of-2. Atomic writes may be merged, and atomic_write_max_sectors would be the limit on a merged atomic write request size. This value is not capped at max_sectors, as the value in max_sectors can be controlled from userspace, and it would only cause trouble if userspace could limit atomic_write_unit_max_bytes and the other atomic write limits.- atomic_write_hw_unit_{min,max} are set by the block driver and are the min/max length of an atomic write unit which the device may support. They both must be a power-of-2. Typically atomic_write_hw_unit_max will hold the same value as atomic_write_hw_max.- atomic_write_unit_{min,max} are derived from atomic_write_hw_unit_{min,max}, max_hw_sectors, and block core limits. Both min and max values must be a power-of-2.- atomic_write_hw_boundary is set by the block driver. If non-zero, it indicates an LBA space boundary at which an atomic write straddles no longer is atomically executed by the disk. The value must be a power-of-2. Note that it would be acceptable to enforce a rule that atomic_write_hw_boundary_sectors is a multiple of atomic_write_hw_unit_max, but the resultant code would be more complicated.All atomic writes limits are by default set 0 to indicate no atomic writesupport. Even though it is assumed by Linux that a logical block can alwaysbe atomically written, we ignore this as it is not of particular interest.Stacked devices are just not supported either for now.An atomic write must always be submitted to the block driver as part of asingle request. As such, only a single BIO must be submitted to the blocklayer for an atomic write. When a single atomic write BIO is submitted, itcannot be split. As such, atomic_write_unit_{max, min}_bytes are limitedby the maximum guaranteed BIO size which will not be required to be split.This max size is calculated by request_queue max segments and the numberof bvecs a BIO can fit, BIO_MAX_VECS. Currently we rely on userspaceissuing a write with iovcnt=1 for pwritev2() - as such, we can rely on eachsegment containing PAGE_SIZE of data, apart from the first+last, which eachcan fit logical block size of data. The first+last will be LBSlength/aligned as we rely on direct IO alignment rules also.New sysfs files are added to report the following atomic write limits:- atomic_write_unit_max_bytes - same as atomic_write_unit_max_sectors in bytes- atomic_write_unit_min_bytes - same as atomic_write_unit_min_sectors in bytes- atomic_write_boundary_bytes - same as atomic_write_hw_boundary_sectors in bytes- atomic_write_max_bytes - same as atomic_write_max_sectors in bytesAtomic writes may only be merged with other atomic writes and only underthe following conditions:- total resultant request length <= atomic_write_max_bytes- the merged write does not straddle a boundaryHelper function bdev_can_atomic_write() is added to indicate whetheratomic writes may be issued to a bdev. If a bdev is a partition, thepartition start must be aligned with both atomic_write_unit_min_sectorsand atomic_write_hw_boundary_sectors.FSes will rely on the block layer to validate that an atomic write BIOsubmitted will be of valid size, so add blk_validate_atomic_write_op_size()for this purpose. Userspace expects an atomic write which is of invalidsize to be rejected with -EINVAL, so add BLK_STS_INVAL for this. Also useBLK_STS_INVAL for when a BIO needs to be split, as this should mean aninvalid size BIO.Flag REQ_ATOMIC is used for indicating an atomic write.Co-developed-by: Himanshu Madhani Signed-off-by: Himanshu Madhani Reviewed-by: Martin K. Petersen Signed-off-by: John Garry Reviewed-by: Keith Busch Link: https://lore.kernel.org/r/20240620125359.2684798-6-john.g.garry@oracle.comSigned-off-by: Jens Axboe List of files: /linux-6.15/Documentation/ABI/stable/sysfs-block

bf20ab53 - blk-throttle: remove CONFIG_BLK_DEV_THROTTLING_LOW

Thu, 09 May 2024 12:11:06 +0000

blk-throttle: remove CONFIG_BLK_DEV_THROTTLING_LOWOne the one hand, it's marked EXPERIMENTAL since 2017, and looks likethere are no users since then, and no testers and no developers, it'sjust not active at all.On the other hand, even if the config is disabled, there are still manyfields in throtl_grp and throtl_data and many functions that are onlyused for throtl low.At last, currently blk-throtl is initialized during disk initialization,and destroyed during disk removal, and it exposes many functions to becalled directly from block layer.Remove throtl low to make code much more cleaner and follow up work mucheasier.Signed-off-by: Yu Kuai Acked-by: Tejun Heo Link: https://lore.kernel.org/r/20240509121107.3195568-2-yukuai1@huaweicloud.comSigned-off-by: Jens Axboe List of files: /linux-6.15/Documentation/ABI/stable/sysfs-block

a4217c67 - block: add a partscan sysfs attribute for disks

Thu, 02 May 2024 13:00:33 +0000

block: add a partscan sysfs attribute for disksUserspace had been unknowingly relying on a non-stable interface ofkernel internals to determine if partition scanning is enabled for agiven disk. Provide a stable interface for this purpose instead.Cc: stable@vger.kernel.org # 6.3+Depends-on: 140ce28dd3be ("block: add a disk_has_partscan helper")Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/linux-block/ZhQJf8mzq_wipkBH@gardel-login/Link: https://lore.kernel.org/r/20240502130033.1958492-3-hch@lst.de[axboe: add links and commit message from Keith]Signed-off-by: Jens Axboe List of files: /linux-6.15/Documentation/ABI/stable/sysfs-block

ebab9426 - Documentation/ABI: Fix typos

Mon, 14 Aug 2023 21:28:20 +0000

Documentation/ABI: Fix typosFix typos in Documentation/ABI. The changes are in descriptions orcomments where they shouldn't affect use of the ABIs.Signed-off-by: Bjorn Helgaas Reviewed-by: Randy Dunlap Link: https://lore.kernel.org/r/20230814212822.193684-2-helgaas@kernel.orgSigned-off-by: Jonathan Corbet List of files: /linux-6.15/Documentation/ABI/stable/sysfs-block

54bdd67d - blk-mq: remove hybrid polling

Mon, 20 Mar 2023 19:49:26 +0000

blk-mq: remove hybrid pollingio_uring provides the only way user space can poll completions, and thatalways sets BLK_POLL_NOSLEEP. This effectively makes hybrid polling deadcode, so remove it and everything supporting it.Hybrid polling was effectively killed off with 9650b453a3d4b1, "block:ignore RWF_HIPRI hint for sync dio", but still potentially reachablethrough io_uring until d729cf9acb93119, "io_uring: don't sleep whenpolling for I/O", but hybrid polling probably should not have beenreachable through that async interface from the beginning.Fixes: 9650b453a3d4 ("block: ignore RWF_HIPRI hint for sync dio")Fixes: d729cf9acb93 ("io_uring: don't sleep when polling for I/O")Signed-off-by: Keith Busch Link: https://lore.kernel.org/r/20230320194926.3353144-1-kbusch@meta.comSigned-off-by: Jens Axboe List of files: /linux-6.15/Documentation/ABI/stable/sysfs-block

e3306221 - docs: sysfs-block: document hidden sysfs entry

Fri, 03 Mar 2023 08:43:23 +0000

docs: sysfs-block: document hidden sysfs entry/sys/block//hidden is undocumented. Document it.Signed-off-by: Sagi Grimberg Reviewed-by: Chaitanya Kulkarni Link: https://lore.kernel.org/r/20230303084323.228098-1-sagi@grimberg.meSigned-off-by: Jens Axboe List of files: /linux-6.15/Documentation/ABI/stable/sysfs-block

c9c77418 - block: save user max_sectors limit

Thu, 05 Jan 2023 20:51:46 +0000

block: save user max_sectors limitThe user can set the max_sectors limit to any valid value via sysfs/sys/block//queue/max_sectors_kb attribute. If the device limitsare ever rescanned, though, the limit reverts back to the potentiallyartificially low BLK_DEF_MAX_SECTORS value.Preserve the user's setting as the max_sectors limit as long as it'svalid. The user can reset back to defaults by writing 0 to the sysfsfile.Signed-off-by: Keith Busch Reviewed-by: Christoph Hellwig Reviewed-by: Martin K. Petersen Link: https://lore.kernel.org/r/20230105205146.3610282-3-kbusch@meta.comSigned-off-by: Jens Axboe List of files: /linux-6.15/Documentation/ABI/stable/sysfs-block

3850e13f - block: export dma_alignment attribute

Fri, 10 Jun 2022 19:58:22 +0000

block: export dma_alignment attributeUser space may want to know how to align their buffers to avoidbouncing. Export the queue attribute.Signed-off-by: Keith Busch Reviewed-by: Johannes Thumshirn Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20220610195830.3574005-4-kbusch@fb.comSigned-off-by: Jens Axboe List of files: /linux-6.15/Documentation/ABI/stable/sysfs-block

20f01f16 - blk-crypto: show crypto capabilities in sysfs

Mon, 24 Jan 2022 21:59:38 +0000

blk-crypto: show crypto capabilities in sysfsAdd sysfs files that expose the inline encryption capabilities ofrequest queues: /sys/block/$disk/queue/crypto/max_dun_bits /sys/block/$disk/queue/crypto/modes/$mode /sys/block/$disk/queue/crypto/num_keyslotsUserspace can use these new files to decide what encryption settings touse, or whether to use inline encryption at all. This also brings thecrypto capabilities in line with the other queue properties, which arealready 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 Signed-off-by: Eric Biggers Link: https://lore.kernel.org/r/20220124215938.2769-4-ebiggers@kernel.orgSigned-off-by: Jens Axboe List of files: /linux-6.15/Documentation/ABI/stable/sysfs-block

8bc2f7c6 - docs: sysfs-block: document virt_boundary_mask

Thu, 09 Dec 2021 00:38:31 +0000

docs: sysfs-block: document virt_boundary_mask/sys/block//queue/virt_boundary_mask is completely undocumented.Document it.Reviewed-by: Bart Van Assche Signed-off-by: Eric Biggers Link: https://lore.kernel.org/r/20211209003833.6396-7-ebiggers@kernel.orgSigned-off-by: Jens Axboe List of files: /linux-6.15/Documentation/ABI/stable/sysfs-block

11630104 - docs: sysfs-block: document stable_writes

Thu, 09 Dec 2021 00:38:30 +0000

docs: sysfs-block: document stable_writes/sys/block//queue/stable_writes is completely undocumented.Document it.Reviewed-by: Bart Van Assche Signed-off-by: Eric Biggers Link: https://lore.kernel.org/r/20211209003833.6396-6-ebiggers@kernel.orgSigned-off-by: Jens Axboe List of files: /linux-6.15/Documentation/ABI/stable/sysfs-block

849ab826 - docs: sysfs-block: fill in missing documentation from queue-sysfs.rst

Thu, 09 Dec 2021 00:38:29 +0000

docs: sysfs-block: fill in missing documentation from queue-sysfs.rstsysfs documentation is supposed to go in Documentation/ABI/.However, /sys/block//queue/* are documented inDocumentation/block/queue-sysfs.rst, and sometimes redundantly inDocumentation/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 inqueue-sysfs.rst only, as well as mentioning the RO/RW status of files.Documentation/ABI/ requires "Date" and "Contact" fields. For the Datefields, 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 Reviewed-by: Hannes Reinecke Reviewed-by: Martin K. Petersen Reviewed-by: Bart Van Assche Signed-off-by: Eric Biggers Link: https://lore.kernel.org/r/20211209003833.6396-5-ebiggers@kernel.orgSigned-off-by: Jens Axboe List of files: /linux-6.15/Documentation/ABI/stable/sysfs-block

8b0551a7 - docs: sysfs-block: add contact for nomerges

Thu, 09 Dec 2021 00:38:28 +0000

docs: sysfs-block: add contact for nomergesThe nomerges file was missing a "Contact" entry. Use linux-block.Reviewed-by: Greg Kroah-Hartman Reviewed-by: Hannes Reinecke Reviewed-by: Martin K. Petersen Reviewed-by: Bart Van Assche Signed-off-by: Eric Biggers Link: https://lore.kernel.org/r/20211209003833.6396-4-ebiggers@kernel.orgSigned-off-by: Jens Axboe List of files: /linux-6.15/Documentation/ABI/stable/sysfs-block

07c9093c - docs: sysfs-block: sort alphabetically

Thu, 09 Dec 2021 00:38:27 +0000

docs: sysfs-block: sort alphabeticallySort the documentation for the files alphabetically by file path so thatthere is a logical order and it's clear where to add new files.With two small exceptions, this patch doesn't change the documentationitself and just reorders it:- In /sys/block///stat, I replaced with to be consistent with the other files.- The description for /sys/block///stat referred to another file "above", which I reworded.Reviewed-by: Greg Kroah-Hartman Reviewed-by: Hannes Reinecke Reviewed-by: Martin K. Petersen Reviewed-by: Bart Van Assche Signed-off-by: Eric Biggers Link: https://lore.kernel.org/r/20211209003833.6396-3-ebiggers@kernel.orgSigned-off-by: Jens Axboe List of files: /linux-6.15/Documentation/ABI/stable/sysfs-block

ae7a7a53 - docs: sysfs-block: move to stable directory

Thu, 09 Dec 2021 00:38:26 +0000

docs: sysfs-block: move to stable directoryThe block layer sysfs ABI is widely used by userspace software and isconsidered stable.Reviewed-by: Martin K. Petersen Reviewed-by: Bart Van Assche Signed-off-by: Eric Biggers Link: https://lore.kernel.org/r/20211209003833.6396-2-ebiggers@kernel.orgSigned-off-by: Jens Axboe List of files: /linux-6.15/Documentation/ABI/stable/sysfs-block