diff options
| author | Damien Le Moal <damien.lemoal@wdc.com> | 2021-01-28 13:47:30 +0900 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-04-13 12:58:07 +0200 |
| commit | 6b4bb49e3418a78af0e35d18d97a926865276ec1 (patch) | |
| tree | 90312a177c8a57b555bfc5b9eaa7e10b128ec4bd /Documentation | |
| parent | 0eb348f4d736d8fa61bd97e16185d873d560aa0f (diff) | |
| download | linux-stable-6b4bb49e3418a78af0e35d18d97a926865276ec1.tar.gz linux-stable-6b4bb49e3418a78af0e35d18d97a926865276ec1.tar.bz2 linux-stable-6b4bb49e3418a78af0e35d18d97a926865276ec1.zip | |
block: introduce zone_write_granularity limit
[ Upstream commit a805a4fa4fa376bbc145762bb8b09caa2fa8af48 ]
Per ZBC and ZAC specifications, host-managed SMR hard-disks mandate that
all writes into sequential write required zones be aligned to the device
physical block size. However, NVMe ZNS does not have this constraint and
allows write operations into sequential zones to be aligned to the
device logical block size. This inconsistency does not help with
software portability across device types.
To solve this, introduce the zone_write_granularity queue limit to
indicate the alignment constraint, in bytes, of write operations into
zones of a zoned block device. This new limit is exported as a
read-only sysfs queue attribute and the helper
blk_queue_zone_write_granularity() introduced for drivers to set this
limit.
The function blk_queue_set_zoned() is modified to set this new limit to
the device logical block size by default. NVMe ZNS devices as well as
zoned nullb devices use this default value as is. The scsi disk driver
is modified to execute the blk_queue_zone_write_granularity() helper to
set the zone write granularity of host-managed SMR disks to the disk
physical block size.
The accessor functions queue_zone_write_granularity() and
bdev_zone_write_granularity() are also introduced.
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@edc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Stable-dep-of: c8f6f88d2592 ("block: Clear zone limits for a non-zoned stacked queue")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/block/queue-sysfs.rst | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/Documentation/block/queue-sysfs.rst b/Documentation/block/queue-sysfs.rst index 2638d3446b79..c8bf8bc3c03a 100644 --- a/Documentation/block/queue-sysfs.rst +++ b/Documentation/block/queue-sysfs.rst @@ -273,4 +273,11 @@ devices are described in the ZBC (Zoned Block Commands) and ZAC do not support zone commands, they will be treated as regular block devices and zoned will report "none". +zone_write_granularity (RO) +--------------------------- +This indicates the alignment constraint, in bytes, for write operations in +sequential zones of zoned block devices (devices with a zoned attributed +that reports "host-managed" or "host-aware"). This value is always 0 for +regular block devices. + Jens Axboe <jens.axboe@oracle.com>, February 2009 |