On Thu, Jul 02, 2020 at 08:19:22PM +0200, Niklas Cassel wrote:
> Add a new max_active zones definition in the sysfs documentation.
> This definition will be common for all devices utilizing the zoned block
> device support in the kernel.
>
> Export max_active_zones according to this new definition for NVMe Zoned
> Namespace devices, ZAC ATA devices (which are treated as SCSI devices by
> the kernel), and ZBC SCSI devices.
>
> Add the new max_active_zones member to struct request_queue, rather
> than as a queue limit, since this property cannot be split across stacking
> drivers.
>
> For SCSI devices, even though max active zones is not part of the ZBC/ZAC
> spec, export max_active_zones as 0, signifying "no limit".
>
> Signed-off-by: Niklas Cassel <niklas.cassel@xxxxxxx>
> Reviewed-by: Javier González <javier@xxxxxxxxxxx>
> ---
> Documentation/block/queue-sysfs.rst | 7 +++++++
> block/blk-sysfs.c | 14 +++++++++++++-
> drivers/nvme/host/zns.c | 1 +
> drivers/scsi/sd_zbc.c | 1 +
> include/linux/blkdev.h | 16 ++++++++++++++++
> 5 files changed, 38 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/block/queue-sysfs.rst b/Documentation/block/queue-sysfs.rst
> index f01cf8530ae4..f261a5c84170 100644
> --- a/Documentation/block/queue-sysfs.rst
> +++ b/Documentation/block/queue-sysfs.rst
> @@ -117,6 +117,13 @@ Maximum number of elements in a DMA scatter/gather list with integrity
> data that will be submitted by the block layer core to the associated
> block driver.
>
> +max_active_zones (RO)
> +---------------------
> +For zoned block devices (zoned attribute indicating "host-managed" or
> +"host-aware"), the sum of zones belonging to any of the zone states:
> +EXPLICIT OPEN, IMPLICIT OPEN or CLOSED, is limited by this value.
> +If this value is 0, there is no limit.
Shouldn't this all be in Documentation/ABI/ to describe the sysfs files?
All other kernel subsystems use that format, why is block special?
> +
> max_open_zones (RO)
> -------------------
> For zoned block devices (zoned attribute indicating "host-managed" or
> diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
> index fa42961e9678..624bb4d85fc7 100644
> --- a/block/blk-sysfs.c
> +++ b/block/blk-sysfs.c
> @@ -310,6 +310,11 @@ static ssize_t queue_max_open_zones_show(struct request_queue *q, char *page)
> return queue_var_show(queue_max_open_zones(q), page);
> }
>
> +static ssize_t queue_max_active_zones_show(struct request_queue *q, char *page)
> +{
> + return queue_var_show(queue_max_active_zones(q), page);
> +}
> +
> static ssize_t queue_nomerges_show(struct request_queue *q, char *page)
> {
> return queue_var_show((blk_queue_nomerges(q) << 1) |
> @@ -677,6 +682,11 @@ static struct queue_sysfs_entry queue_max_open_zones_entry = {
> .show = queue_max_open_zones_show,
> };
>
> +static struct queue_sysfs_entry queue_max_active_zones_entry = {
> + .attr = {.name = "max_active_zones", .mode = 0444 },
> + .show = queue_max_active_zones_show,
> +};
__ATTR_RO()?
thanks,
greg k-h
