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authorLinus Torvalds <torvalds@linux-foundation.org>2024-07-15 14:20:22 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2024-07-15 14:20:22 -0700
commit3e7819886281e077e82006fe4804b0d6b0f5643b (patch)
tree40766af623d8a1dde0edaee8b6abc496efbcc615 /Documentation
parent3a56e241732975c2c1247047ddbfc0ac6f6a4905 (diff)
parent3c1743a685b19bc17cf65af4a2eb149fd3b15c50 (diff)
Merge tag 'for-6.11/block-20240710' of git://git.kernel.dk/linux
Pull block updates from Jens Axboe: - NVMe updates via Keith: - Device initialization memory leak fixes (Keith) - More constants defined (Weiwen) - Target debugfs support (Hannes) - PCIe subsystem reset enhancements (Keith) - Queue-depth multipath policy (Redhat and PureStorage) - Implement get_unique_id (Christoph) - Authentication error fixes (Gaosheng) - MD updates via Song - sync_action fix and refactoring (Yu Kuai) - Various small fixes (Christoph Hellwig, Li Nan, and Ofir Gal, Yu Kuai, Benjamin Marzinski, Christophe JAILLET, Yang Li) - Fix loop detach/open race (Gulam) - Fix lower control limit for blk-throttle (Yu) - Add module descriptions to various drivers (Jeff) - Add support for atomic writes for block devices, and statx reporting for same. Includes SCSI and NVMe (John, Prasad, Alan) - Add IO priority information to block trace points (Dongliang) - Various zone improvements and tweaks (Damien) - mq-deadline tag reservation improvements (Bart) - Ignore direct reclaim swap writes in writeback throttling (Baokun) - Block integrity improvements and fixes (Anuj) - Add basic support for rust based block drivers. Has a dummy null_blk variant for now (Andreas) - Series converting driver settings to queue limits, and cleanups and fixes related to that (Christoph) - Cleanup for poking too deeply into the bvec internals, in preparation for DMA mapping API changes (Christoph) - Various minor tweaks and fixes (Jiapeng, John, Kanchan, Mikulas, Ming, Zhu, Damien, Christophe, Chaitanya) * tag 'for-6.11/block-20240710' of git://git.kernel.dk/linux: (206 commits) floppy: add missing MODULE_DESCRIPTION() macro loop: add missing MODULE_DESCRIPTION() macro ublk_drv: add missing MODULE_DESCRIPTION() macro xen/blkback: add missing MODULE_DESCRIPTION() macro block/rnbd: Constify struct kobj_type block: take offset into account in blk_bvec_map_sg again block: fix get_max_segment_size() warning loop: Don't bother validating blocksize virtio_blk: Don't bother validating blocksize null_blk: Don't bother validating blocksize block: Validate logical block size in blk_validate_limits() virtio_blk: Fix default logical block size fallback nvmet-auth: fix nvmet_auth hash error handling nvme: implement ->get_unique_id block: pass a phys_addr_t to get_max_segment_size block: add a bvec_phys helper blk-lib: check for kill signal in ioctl BLKZEROOUT block: limit the Write Zeroes to manually writing zeroes fallback block: refacto blkdev_issue_zeroout block: move read-only and supported checks into (__)blkdev_issue_zeroout ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/ABI/stable/sysfs-block53
-rw-r--r--Documentation/block/data-integrity.rst49
-rw-r--r--Documentation/block/writeback_cache_control.rst67
3 files changed, 94 insertions, 75 deletions
diff --git a/Documentation/ABI/stable/sysfs-block b/Documentation/ABI/stable/sysfs-block
index 831f19a32e08..cea8856f798d 100644
--- a/Documentation/ABI/stable/sysfs-block
+++ b/Documentation/ABI/stable/sysfs-block
@@ -21,6 +21,59 @@ Description:
device is offset from the internal allocation unit's
natural alignment.
+What: /sys/block/<disk>/atomic_write_max_bytes
+Date: February 2024
+Contact: Himanshu Madhani <himanshu.madhani@oracle.com>
+Description:
+ [RO] This parameter specifies the maximum atomic write
+ size reported by the device. This parameter is relevant
+ for merging of writes, where a merged atomic write
+ operation must not exceed this number of bytes.
+ This parameter may be greater than the value in
+ atomic_write_unit_max_bytes as
+ atomic_write_unit_max_bytes will be rounded down to a
+ power-of-two and atomic_write_unit_max_bytes may also be
+ limited by some other queue limits, such as max_segments.
+ This parameter - along with atomic_write_unit_min_bytes
+ and atomic_write_unit_max_bytes - will not be larger than
+ max_hw_sectors_kb, but may be larger than max_sectors_kb.
+
+
+What: /sys/block/<disk>/atomic_write_unit_min_bytes
+Date: February 2024
+Contact: Himanshu Madhani <himanshu.madhani@oracle.com>
+Description:
+ [RO] This parameter specifies the smallest block which can
+ be written atomically with an atomic write operation. All
+ atomic write operations must begin at a
+ atomic_write_unit_min boundary and must be multiples of
+ atomic_write_unit_min. This value must be a power-of-two.
+
+
+What: /sys/block/<disk>/atomic_write_unit_max_bytes
+Date: February 2024
+Contact: Himanshu Madhani <himanshu.madhani@oracle.com>
+Description:
+ [RO] This parameter defines the largest block which can be
+ written atomically with an atomic write operation. This
+ value must be a multiple of atomic_write_unit_min and must
+ be a power-of-two. This value will not be larger than
+ atomic_write_max_bytes.
+
+
+What: /sys/block/<disk>/atomic_write_boundary_bytes
+Date: February 2024
+Contact: Himanshu Madhani <himanshu.madhani@oracle.com>
+Description:
+ [RO] A device may need to internally split an atomic write I/O
+ which straddles a given logical block address boundary. This
+ parameter specifies the size in bytes of the atomic boundary if
+ one is reported by the device. This value must be a
+ power-of-two and at least the size as in
+ atomic_write_unit_max_bytes.
+ Any attempt to merge atomic write I/Os must not result in a
+ merged I/O which crosses this boundary (if any).
+
What: /sys/block/<disk>/diskseq
Date: February 2021
diff --git a/Documentation/block/data-integrity.rst b/Documentation/block/data-integrity.rst
index 6a760c0eb192..99905e880a0e 100644
--- a/Documentation/block/data-integrity.rst
+++ b/Documentation/block/data-integrity.rst
@@ -153,18 +153,11 @@ bio_free() will automatically free the bip.
4.2 Block Device
----------------
-Because the format of the protection data is tied to the physical
-disk, each block device has been extended with a block integrity
-profile (struct blk_integrity). This optional profile is registered
-with the block layer using blk_integrity_register().
-
-The profile contains callback functions for generating and verifying
-the protection data, as well as getting and setting application tags.
-The profile also contains a few constants to aid in completing,
-merging and splitting the integrity metadata.
+Block devices can set up the integrity information in the integrity
+sub-struture of the queue_limits structure.
Layered block devices will need to pick a profile that's appropriate
-for all subdevices. blk_integrity_compare() can help with that. DM
+for all subdevices. queue_limits_stack_integrity() can help with that. DM
and MD linear, RAID0 and RAID1 are currently supported. RAID4/5/6
will require extra work due to the application tag.
@@ -250,42 +243,6 @@ will require extra work due to the application tag.
integrity upon completion.
-5.4 Registering A Block Device As Capable Of Exchanging Integrity Metadata
---------------------------------------------------------------------------
-
- To enable integrity exchange on a block device the gendisk must be
- registered as capable:
-
- `int blk_integrity_register(gendisk, blk_integrity);`
-
- The blk_integrity struct is a template and should contain the
- following::
-
- static struct blk_integrity my_profile = {
- .name = "STANDARDSBODY-TYPE-VARIANT-CSUM",
- .generate_fn = my_generate_fn,
- .verify_fn = my_verify_fn,
- .tuple_size = sizeof(struct my_tuple_size),
- .tag_size = <tag bytes per hw sector>,
- };
-
- 'name' is a text string which will be visible in sysfs. This is
- part of the userland API so chose it carefully and never change
- it. The format is standards body-type-variant.
- E.g. T10-DIF-TYPE1-IP or T13-EPP-0-CRC.
-
- 'generate_fn' generates appropriate integrity metadata (for WRITE).
-
- 'verify_fn' verifies that the data buffer matches the integrity
- metadata.
-
- 'tuple_size' must be set to match the size of the integrity
- metadata per sector. I.e. 8 for DIF and EPP.
-
- 'tag_size' must be set to identify how many bytes of tag space
- are available per hardware sector. For DIF this is either 2 or
- 0 depending on the value of the Control Mode Page ATO bit.
-
----------------------------------------------------------------------
2007-12-24 Martin K. Petersen <martin.petersen@oracle.com>
diff --git a/Documentation/block/writeback_cache_control.rst b/Documentation/block/writeback_cache_control.rst
index b208488d0aae..c3707d071780 100644
--- a/Documentation/block/writeback_cache_control.rst
+++ b/Documentation/block/writeback_cache_control.rst
@@ -46,41 +46,50 @@ worry if the underlying devices need any explicit cache flushing and how
the Forced Unit Access is implemented. The REQ_PREFLUSH and REQ_FUA flags
may both be set on a single bio.
+Feature settings for block drivers
+----------------------------------
-Implementation details for bio based block drivers
---------------------------------------------------------------
+For devices that do not support volatile write caches there is no driver
+support required, the block layer completes empty REQ_PREFLUSH requests before
+entering the driver and strips off the REQ_PREFLUSH and REQ_FUA bits from
+requests that have a payload.
-These drivers will always see the REQ_PREFLUSH and REQ_FUA bits as they sit
-directly below the submit_bio interface. For remapping drivers the REQ_FUA
-bits need to be propagated to underlying devices, and a global flush needs
-to be implemented for bios with the REQ_PREFLUSH bit set. For real device
-drivers that do not have a volatile cache the REQ_PREFLUSH and REQ_FUA bits
-on non-empty bios can simply be ignored, and REQ_PREFLUSH requests without
-data can be completed successfully without doing any work. Drivers for
-devices with volatile caches need to implement the support for these
-flags themselves without any help from the block layer.
+For devices with volatile write caches the driver needs to tell the block layer
+that it supports flushing caches by setting the
+ BLK_FEAT_WRITE_CACHE
-Implementation details for request_fn based block drivers
----------------------------------------------------------
+flag in the queue_limits feature field. For devices that also support the FUA
+bit the block layer needs to be told to pass on the REQ_FUA bit by also setting
+the
-For devices that do not support volatile write caches there is no driver
-support required, the block layer completes empty REQ_PREFLUSH requests before
-entering the driver and strips off the REQ_PREFLUSH and REQ_FUA bits from
-requests that have a payload. For devices with volatile write caches the
-driver needs to tell the block layer that it supports flushing caches by
-doing::
+ BLK_FEAT_FUA
+
+flag in the features field of the queue_limits structure.
+
+Implementation details for bio based block drivers
+--------------------------------------------------
+
+For bio based drivers the REQ_PREFLUSH and REQ_FUA bit are simply passed on to
+the driver if the driver sets the BLK_FEAT_WRITE_CACHE flag and the driver
+needs to handle them.
+
+*NOTE*: The REQ_FUA bit also gets passed on when the BLK_FEAT_FUA flags is
+_not_ set. Any bio based driver that sets BLK_FEAT_WRITE_CACHE also needs to
+handle REQ_FUA.
- blk_queue_write_cache(sdkp->disk->queue, true, false);
+For remapping drivers the REQ_FUA bits need to be propagated to underlying
+devices, and a global flush needs to be implemented for bios with the
+REQ_PREFLUSH bit set.
-and handle empty REQ_OP_FLUSH requests in its prep_fn/request_fn. Note that
-REQ_PREFLUSH requests with a payload are automatically turned into a sequence
-of an empty REQ_OP_FLUSH request followed by the actual write by the block
-layer. For devices that also support the FUA bit the block layer needs
-to be told to pass through the REQ_FUA bit using::
+Implementation details for blk-mq drivers
+-----------------------------------------
- blk_queue_write_cache(sdkp->disk->queue, true, true);
+When the BLK_FEAT_WRITE_CACHE flag is set, REQ_OP_WRITE | REQ_PREFLUSH requests
+with a payload are automatically turned into a sequence of a REQ_OP_FLUSH
+request followed by the actual write by the block layer.
-and the driver must handle write requests that have the REQ_FUA bit set
-in prep_fn/request_fn. If the FUA bit is not natively supported the block
-layer turns it into an empty REQ_OP_FLUSH request after the actual write.
+When the BLK_FEAT_FUA flags is set, the REQ_FUA bit is simply passed on for the
+REQ_OP_WRITE request, else a REQ_OP_FLUSH request is sent by the block layer
+after the completion of the write request for bio submissions with the REQ_FUA
+bit set.