linux-toradex.git/block/blk-sysfs.c, branch v6.10-rc3

blk-throttle: delay initialization until configuration

2024-05-09T15:44:56+00:00

Other cgroup policy like bfq, iocost are lazy-initialized when they are
configured for the first time for the device, but blk-throttle is
initialized unconditionally from blkcg_init_disk().

Delay initialization of blk-throttle as well, to save some cpu and
memory overhead if it's not configured.

Noted that once it's initialized, it can't be destroyed until disk
removal, even if it's disabled.

Signed-off-by: Yu Kuai 
Link: https://lore.kernel.org/r/20240509121107.3195568-3-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe

blk-throttle: remove CONFIG_BLK_DEV_THROTTLING_LOW

2024-05-09T15:44:55+00:00

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 
Acked-by: Tejun Heo 
Link: https://lore.kernel.org/r/20240509121107.3195568-2-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe

block: Allow zero value of max_zone_append_sectors queue limit

2024-04-17T14:44:03+00:00

In preparation for adding a generic zone append emulation using zone
write plugging, allow device drivers supporting zoned block device to
set a the max_zone_append_sectors queue limit of a device to 0 to
indicate the lack of native support for zone append operations and that
the block layer should emulate these operations using regular write
operations.

blk_queue_max_zone_append_sectors() is modified to allow passing 0 as
the max_zone_append_sectors argument. The function
queue_max_zone_append_sectors() is also modified to ensure that the
minimum of the max_hw_sectors and chunk_sectors limit is used whenever
the max_zone_append_sectors limit is 0. This minimum is consistent with
the value set for the max_zone_append_sectors limit by the function
blk_validate_zoned_limits() when limits for a queue are validated.

The helper functions queue_emulates_zone_append() and
bdev_emulates_zone_append() are added to test if a queue (or block
device) emulates zone append operations.

In order for blk_revalidate_disk_zones() to accept zoned block devices
relying on zone append emulation, the direct check to the
max_zone_append_sectors queue limit of the disk is replaced by a check
using the value returned by queue_max_zone_append_sectors(). Similarly,
queue_zone_append_max_show() is modified to use the same accessor so
that the sysfs attribute advertizes the non-zero limit that will be
used, regardless if it is for native or emulated commands.

For stacking drivers, a top device should not need to care if the
underlying devices have native or emulated zone append operations.
blk_stack_limits() is thus modified to set the top device
max_zone_append_sectors limit using the new accessor
queue_limits_max_zone_append_sectors(). queue_max_zone_append_sectors()
is modified to use this function as well. Stacking drivers that require
zone append emulation, e.g. dm-crypt, can still request this feature by
calling blk_queue_max_zone_append_sectors() with a 0 limit.

Signed-off-by: Damien Le Moal 
Reviewed-by: Hannes Reinecke 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Bart Van Assche 
Tested-by: Hans Holmberg 
Tested-by: Dennis Maisenbacher 
Reviewed-by: Martin K. Petersen 
Link: https://lore.kernel.org/r/20240408014128.205141-10-dlemoal@kernel.org
Signed-off-by: Jens Axboe

block: use queue_limits_commit_update in queue_discard_max_store

2024-02-13T15:56:59+00:00

Convert queue_discard_max_store to use queue_limits_commit_update to
check and update the max_discard_sectors limit and freeze the queue
before doing so to ensure we don't have requests in flight while
changing the limits.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Keith Busch 
Reviewed-by: Chaitanya Kulkarni 
Reviewed-by: Ming Lei 
Reviewed-by: Damien Le Moal 
Reviewed-by: Martin K. Petersen 
Reviewed-by: Hannes Reinecke 
Link: https://lore.kernel.org/r/20240213073425.1621680-8-hch@lst.de
Signed-off-by: Jens Axboe

block: add a max_user_discard_sectors queue limit

2024-02-13T15:56:59+00:00

Add a new max_user_discard_sectors limit that mirrors max_user_sectors
and stores the value that the user manually set.  This now allows
updates of the max_hw_discard_sectors to not worry about the user
limit.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Keith Busch 
Reviewed-by: Chaitanya Kulkarni 
Reviewed-by: Ming Lei 
Reviewed-by: Martin K. Petersen 
Reviewed-by: Hannes Reinecke 
Link: https://lore.kernel.org/r/20240213073425.1621680-7-hch@lst.de
Signed-off-by: Jens Axboe

block: use queue_limits_commit_update in queue_max_sectors_store

2024-02-13T15:56:59+00:00

Convert queue_max_sectors_store to use queue_limits_commit_update to
check and update the max_sectors limit and freeze the queue before
doing so to ensure we don't have requests in flight while changing
the limits.

Note that this removes the previously held queue_lock that doesn't
protect against any other reader or writer.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Keith Busch 
Reviewed-by: John Garry 
Reviewed-by: Chaitanya Kulkarni 
Reviewed-by: Ming Lei 
Reviewed-by: Damien Le Moal 
Reviewed-by: Martin K. Petersen 
Reviewed-by: Hannes Reinecke 
Link: https://lore.kernel.org/r/20240213073425.1621680-6-hch@lst.de
Signed-off-by: Jens Axboe

Merge tag 'for-6.8/block-2024-01-08' of git://git.kernel.dk/linux

2024-01-11T21:58:04+00:00

Pull block updates from Jens Axboe:
 "Pretty quiet round this time around. This contains:

   - NVMe updates via Keith:
        - nvme fabrics spec updates (Guixin, Max)
        - nvme target udpates (Guixin, Evan)
        - nvme attribute refactoring (Daniel)
        - nvme-fc numa fix (Keith)

   - MD updates via Song:
        - Fix/Cleanup RCU usage from conf->disks[i].rdev (Yu Kuai)
        - Fix raid5 hang issue (Junxiao Bi)
        - Add Yu Kuai as Reviewer of the md subsystem
        - Remove deprecated flavors (Song Liu)
        - raid1 read error check support (Li Nan)
        - Better handle events off-by-1 case (Alex Lyakas)

   - Efficiency improvements for passthrough (Kundan)

   - Support for mapping integrity data directly (Keith)

   - Zoned write fix (Damien)

   - rnbd fixes (Kees, Santosh, Supriti)

   - Default to a sane discard size granularity (Christoph)

   - Make the default max transfer size naming less confusing
     (Christoph)

   - Remove support for deprecated host aware zoned model (Christoph)

   - Misc fixes (me, Li, Matthew, Min, Ming, Randy, liyouhong, Daniel,
     Bart, Christoph)"

* tag 'for-6.8/block-2024-01-08' of git://git.kernel.dk/linux: (78 commits)
  block: Treat sequential write preferred zone type as invalid
  block: remove disk_clear_zoned
  sd: remove the !ZBC && blk_queue_is_zoned case in sd_read_block_characteristics
  drivers/block/xen-blkback/common.h: Fix spelling typo in comment
  blk-cgroup: fix rcu lockdep warning in blkg_lookup()
  blk-cgroup: don't use removal safe list iterators
  block: floor the discard granularity to the physical block size
  mtd_blkdevs: use the default discard granularity
  bcache: use the default discard granularity
  zram: use the default discard granularity
  null_blk: use the default discard granularity
  nbd: use the default discard granularity
  ubd: use the default discard granularity
  block: default the discard granularity to sector size
  bcache: discard_granularity should not be smaller than a sector
  block: remove two comments in bio_split_discard
  block: rename and document BLK_DEF_MAX_SECTORS
  loop: don't abuse BLK_DEF_MAX_SECTORS
  aoe: don't abuse BLK_DEF_MAX_SECTORS
  null_blk: don't cap max_hw_sectors to BLK_DEF_MAX_SECTORS
  ...

block: rename and document BLK_DEF_MAX_SECTORS

2023-12-27T17:46:01+00:00

Give BLK_DEF_MAX_SECTORS a _CAP postfix and document what it is used for.

Signed-off-by: Christoph Hellwig 
Link: https://lore.kernel.org/r/20231227092305.279567-5-hch@lst.de
Signed-off-by: Jens Axboe

block: remove support for the host aware zone model

2023-12-20T03:17:43+00:00

When zones were first added the SCSI and ATA specs, two different
models were supported (in addition to the drive managed one that
is invisible to the host):

 - host managed where non-conventional zones there is strict requirement
   to write at the write pointer, or else an error is returned
 - host aware where a write point is maintained if writes always happen
   at it, otherwise it is left in an under-defined state and the
   sequential write preferred zones behave like conventional zones
   (probably very badly performing ones, though)

Not surprisingly this lukewarm model didn't prove to be very useful and
was finally removed from the ZBC and SBC specs (NVMe never implemented
it).  Due to to the easily disappearing write pointer host software
could never rely on the write pointer to actually be useful for say
recovery.

Fortunately only a few HDD prototypes shipped using this model which
never made it to mass production.  Drop the support before it is too
late.  Note that any such host aware prototype HDD can still be used
with Linux as we'll now treat it as a conventional HDD.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Martin K. Petersen 
Link: https://lore.kernel.org/r/20231217165359.604246-4-hch@lst.de
Signed-off-by: Jens Axboe

block: Document the role of the two attribute groups

2023-11-29T17:18:38+00:00

It is nontrivial to derive the role of the two attribute groups in source
file block/blk-sysfs.c. Hence add a comment that explains their roles. See
also commit 6d85ebf95c44 ("blk-sysfs: add a new attr_group for blk_mq").

Cc: Christoph Hellwig 
Cc: Yu Kuai 
Signed-off-by: Bart Van Assche 
Link: https://lore.kernel.org/r/20231128194019.72762-1-bvanassche@acm.org
Signed-off-by: Jens Axboe