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2025-05-06block: introduce a write_stream_granularity queue limitChristoph Hellwig
Export the granularity that write streams should be discarded with, as it is essential for making good use of them. Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Nitesh Shetty <nj.shetty@samsung.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Keith Busch <kbusch@kernel.org> Signed-off-by: Kanchan Joshi <joshi.k@samsung.com> Link: https://lore.kernel.org/r/20250506121732.8211-5-joshi.k@samsung.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-05-06block: introduce max_write_streams queue limitKeith Busch
Drivers with hardware that support write streams need a way to export how many are available so applications can generically query this. Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Nitesh Shetty <nj.shetty@samsung.com> Signed-off-by: Keith Busch <kbusch@kernel.org> [hch: renamed hints to streams, removed stacking] Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Kanchan Joshi <joshi.k@samsung.com> Link: https://lore.kernel.org/r/20250506121732.8211-4-joshi.k@samsung.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-04-17docs: ABI: replace mcroce@microsoft.com with new Meta addressAhmad Fatoum
The 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.de Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de> Acked-by: Matteo Croce <teknoraver@meta.com> Link: https://lore.kernel.org/all/BYAPR15MB2504E4B02DFFB1E55871955DA1062@BYAPR15MB2504.namprd15.prod.outlook.com/ Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Matteo Croce <teknoraver@meta.com> Cc: Sascha Hauer <kernel@pengutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-20docs: sysfs-block: Clarify integrity sysfs attributesMilan Broz
The /sys/block/<disk>/integrity fields are historically set if T10 protection Information is enabled. It is not set if some upper layer uses integrity metadata. Document it. Signed-off-by: Milan Broz <gmazyland@gmail.com> Co-developed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20250318154447.370786-1-gmazyland@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2025-02-10blk-crypto: show supported key types in sysfsEric Biggers
Add sysfs files that indicate which type(s) of keys are supported by the inline encryption hardware associated with a particular request queue: /sys/block/$disk/queue/crypto/hw_wrapped_keys /sys/block/$disk/queue/crypto/raw_keys Userspace can use the presence or absence of these files to decide what encyption settings to use. Don't use a single key_type file, as devices might support both key types at the same time. Signed-off-by: Eric Biggers <ebiggers@google.com> Tested-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org> # sm8650 Link: https://lore.kernel.org/r/20250204060041.409950-3-ebiggers@kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-11-18Merge tag 'for-6.13/block-20241118' of git://git.kernel.dk/linuxLinus Torvalds
Pull block updates from Jens Axboe: - NVMe updates via Keith: - Use uring_cmd helper (Pavel) - Host Memory Buffer allocation enhancements (Christoph) - Target persistent reservation support (Guixin) - Persistent reservation tracing (Guixen) - NVMe 2.1 specification support (Keith) - Rotational Meta Support (Matias, Wang, Keith) - Volatile cache detection enhancment (Guixen) - MD updates via Song: - Maintainers update - raid5 sync IO fix - Enhance handling of faulty and blocked devices - raid5-ppl atomic improvement - md-bitmap fix - Support for manually defining embedded partition tables - Zone append fixes and cleanups - Stop sending the queued requests in the plug list to the driver ->queue_rqs() handle in reverse order. - Zoned write plug cleanups - Cleanups disk stats tracking and add support for disk stats for passthrough IO - Add preparatory support for file system atomic writes - Add lockdep support for queue freezing. Already found a bunch of issues, and some fixes for that are in here. More will be coming. - Fix race between queue stopping/quiescing and IO queueing - ublk recovery improvements - Fix ublk mmap for 64k pages - Various fixes and cleanups * tag 'for-6.13/block-20241118' of git://git.kernel.dk/linux: (118 commits) MAINTAINERS: Update git tree for mdraid subsystem block: make struct rq_list available for !CONFIG_BLOCK block/genhd: use seq_put_decimal_ull for diskstats decimal values block: don't reorder requests in blk_mq_add_to_batch block: don't reorder requests in blk_add_rq_to_plug block: add a rq_list type block: remove rq_list_move virtio_blk: reverse request order in virtio_queue_rqs nvme-pci: reverse request order in nvme_queue_rqs btrfs: validate queue limits block: export blk_validate_limits nvmet: add tracing of reservation commands nvme: parse reservation commands's action and rtype to string nvmet: report ns's vwc not present md/raid5: Increase r5conf.cache_name size block: remove the ioprio field from struct request block: remove the write_hint field from struct request nvme: check ns's volatile write cache not present nvme: add rotational support nvme: use command set independent id ns if available ...
2024-11-14mm, doc: update read_ahead_kb for MADV_HUGEPAGEYafang Shao
MADV_HUGEPAGE is a new addition to readahead with behavior distinct from normal pages. To prevent confusion, we should update the documentation accordingly. Link: https://lkml.kernel.org/r/20241113150711.1685-1-laoar.shao@gmail.com Signed-off-by: Yafang Shao <laoar.shao@gmail.com> Cc: David Hildenbrand <david@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-10-22block: enable passthrough command statisticsKeith Busch
Applications using the passthrough interfaces for IO want to continue seeing the disk stats. These requests had been fenced off from this block layer feature. While the block layer doesn't necessarily know what a 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 to be enabled with the /sys/block/<dev>/queue/iostats_passthrough attribute. Signed-off-by: Keith Busch <kbusch@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20241007153236.2818562-1-kbusch@meta.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-06-20block: Add core atomic write supportJohn Garry
Add 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 flag New 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 write support. Even though it is assumed by Linux that a logical block can always be 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 a single request. As such, only a single BIO must be submitted to the block layer for an atomic write. When a single atomic write BIO is submitted, it cannot be split. As such, atomic_write_unit_{max, min}_bytes are limited by 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 number of bvecs a BIO can fit, BIO_MAX_VECS. Currently we rely on userspace issuing a write with iovcnt=1 for pwritev2() - as such, we can rely on each segment containing PAGE_SIZE of data, apart from the first+last, which each can fit logical block size of data. The first+last will be LBS length/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 bytes Atomic writes may only be merged with other atomic writes and only under the following conditions: - total resultant request length <= atomic_write_max_bytes - the merged write does not straddle a boundary Helper function bdev_can_atomic_write() is added to indicate whether atomic writes may be issued to a bdev. If a bdev is a partition, the partition start must be aligned with both atomic_write_unit_min_sectors and atomic_write_hw_boundary_sectors. FSes will rely on the block layer to validate that an atomic write BIO submitted will be of valid size, so add blk_validate_atomic_write_op_size() for this purpose. Userspace expects an atomic write which is of invalid size to be rejected with -EINVAL, so add BLK_STS_INVAL for this. Also use BLK_STS_INVAL for when a BIO needs to be split, as this should mean an invalid size BIO. Flag REQ_ATOMIC is used for indicating an atomic write. Co-developed-by: Himanshu Madhani <himanshu.madhani@oracle.com> Signed-off-by: Himanshu Madhani <himanshu.madhani@oracle.com> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: John Garry <john.g.garry@oracle.com> Reviewed-by: Keith Busch <kbusch@kernel.org> Link: https://lore.kernel.org/r/20240620125359.2684798-6-john.g.garry@oracle.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-05-09blk-throttle: remove CONFIG_BLK_DEV_THROTTLING_LOWYu Kuai
One the one hand, it's marked EXPERIMENTAL since 2017, and looks like there are no users since then, and no testers and no developers, it's just not active at all. On the other hand, even if the config is disabled, there are still many fields in throtl_grp and throtl_data and many functions that are only used for throtl low. At last, currently blk-throtl is initialized during disk initialization, and destroyed during disk removal, and it exposes many functions to be called directly from block layer. Remove throtl low to make code much more cleaner and follow up work much easier. Signed-off-by: Yu Kuai <yukuai3@huawei.com> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20240509121107.3195568-2-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-05-03block: add a partscan sysfs attribute for disksChristoph Hellwig
Userspace had been unknowingly relying on a non-stable interface of kernel internals to determine if partition scanning is enabled for a given 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 <hch@lst.de> 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 <axboe@kernel.dk>
2023-08-18Documentation/ABI: Fix typosBjorn Helgaas
Fix typos in Documentation/ABI. The changes are in descriptions or comments where they shouldn't affect use of the ABIs. Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Randy Dunlap <rdunlap@infradead.org> Link: https://lore.kernel.org/r/20230814212822.193684-2-helgaas@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2023-03-20blk-mq: remove hybrid pollingKeith Busch
io_uring provides the only way user space can poll completions, and that always sets BLK_POLL_NOSLEEP. This effectively makes hybrid polling dead code, 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 reachable through io_uring until d729cf9acb93119, "io_uring: don't sleep when polling for I/O", but hybrid polling probably should not have been reachable 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 <kbusch@kernel.org> Link: https://lore.kernel.org/r/20230320194926.3353144-1-kbusch@meta.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-03-07docs: sysfs-block: document hidden sysfs entrySagi Grimberg
/sys/block/<disk>/hidden is undocumented. Document it. Signed-off-by: Sagi Grimberg <sagi@grimberg.me> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Link: https://lore.kernel.org/r/20230303084323.228098-1-sagi@grimberg.me Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29block: save user max_sectors limitKeith Busch
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>
2022-06-27block: export dma_alignment attributeKeith Busch
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>
2022-02-28blk-crypto: show crypto capabilities in sysfsEric Biggers
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>
2022-01-09docs: sysfs-block: document virt_boundary_maskEric Biggers
/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>
2022-01-09docs: sysfs-block: document stable_writesEric Biggers
/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>
2022-01-09docs: sysfs-block: fill in missing documentation from queue-sysfs.rstEric Biggers
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>
2022-01-09docs: sysfs-block: add contact for nomergesEric Biggers
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>
2022-01-09docs: sysfs-block: sort alphabeticallyEric Biggers
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>
2022-01-09docs: sysfs-block: move to stable directoryEric Biggers
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>