[PATCH 0/2] Export max open zones and max active zones to sysfs

[Niklas Cassel <niklas.cassel@wdc.com>]

Export max open zones and max active zones to sysfs.

This patch series depends on the Zoned Namespace Command Set series:
https://lore.kernel.org/linux-nvme/20200615233424.13458-1-keith.busch@wdc.com/


All zoned block devices in the kernel utilize the "zoned block device
support" (CONFIG_BLK_DEV_ZONED).

The Zoned Namespace Command Set Specification defines two different
resource limits: Max Open Resources and Max Active Resources.

The ZAC and ZBC standards define a MAXIMUM NUMBER OF OPEN SEQUENTIAL WRITE
REQUIRED ZONES field.


Since the ZNS Max Open Resources field has the same purpose as the ZAC/ZBC
field, (the ZNS field is 0's based, the ZAC/ZBC field isn't), create a
common "max_open_zones" definition in the sysfs documentation, and export
both the ZNS field and the ZAC/ZBC field according to this new common
definition.

The ZNS Max Active Resources field does not have an equivalent field in
ZAC/ZBC, however, since both ZAC/ZBC and ZNS utilize the "zoned block
device support" in the kernel, create a "max_active_zones" definition in
the sysfs documentation, similar to "max_open_zones", and export it
according to this new definition. For ZAC/ZBC devices, this field will be
exported as 0, meaning "no limit".


Niklas Cassel (2):
  block: add max_open_zones to blk-sysfs
  block: add max_active_zones to blk-sysfs

 Documentation/block/queue-sysfs.rst | 14 ++++++++++
 block/blk-sysfs.c                   | 27 +++++++++++++++++++
 drivers/nvme/host/zns.c             |  2 ++
 drivers/scsi/sd_zbc.c               |  5 ++++
 include/linux/blkdev.h              | 40 +++++++++++++++++++++++++++++
 5 files changed, 88 insertions(+)

-- 
2.26.2