On 2020/07/03 3:20, Niklas Cassel wrote:
> Add a new max_open_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 open 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_open_zones member to struct request_queue, rather
> than as a queue limit, since this property cannot be split across stacking
> drivers.
>
> Signed-off-by: Niklas Cassel <niklas.cassel@xxxxxxx>
> Reviewed-by: Javier González <javier@xxxxxxxxxxx>
> ---
> Documentation/block/queue-sysfs.rst | 7 +++++++
> block/blk-sysfs.c | 15 +++++++++++++++
> drivers/nvme/host/zns.c | 1 +
> drivers/scsi/sd_zbc.c | 4 ++++
> include/linux/blkdev.h | 16 ++++++++++++++++
> 5 files changed, 43 insertions(+)
>
> diff --git a/Documentation/block/queue-sysfs.rst b/Documentation/block/queue-sysfs.rst
> index 6a8513af9201..f01cf8530ae4 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_open_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 or IMPLICIT OPEN, is limited by this value.
> +If this value is 0, there is no limit.
> +
> max_sectors_kb (RW)
> -------------------
> This is the maximum number of kilobytes that the block layer will allow
> diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
> index 02643e149d5e..fa42961e9678 100644
> --- a/block/blk-sysfs.c
> +++ b/block/blk-sysfs.c
> @@ -305,6 +305,11 @@ static ssize_t queue_nr_zones_show(struct request_queue *q, char *page)
> return queue_var_show(blk_queue_nr_zones(q), page);
> }
>
> +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_nomerges_show(struct request_queue *q, char *page)
> {
> return queue_var_show((blk_queue_nomerges(q) << 1) |
> @@ -667,6 +672,11 @@ static struct queue_sysfs_entry queue_nr_zones_entry = {
> .show = queue_nr_zones_show,
> };
>
> +static struct queue_sysfs_entry queue_max_open_zones_entry = {
> + .attr = {.name = "max_open_zones", .mode = 0444 },
> + .show = queue_max_open_zones_show,
> +};
> +
> static struct queue_sysfs_entry queue_nomerges_entry = {
> .attr = {.name = "nomerges", .mode = 0644 },
> .show = queue_nomerges_show,
> @@ -765,6 +775,7 @@ static struct attribute *queue_attrs[] = {
> &queue_nonrot_entry.attr,
> &queue_zoned_entry.attr,
> &queue_nr_zones_entry.attr,
> + &queue_max_open_zones_entry.attr,
> &queue_nomerges_entry.attr,
> &queue_rq_affinity_entry.attr,
> &queue_iostats_entry.attr,
> @@ -792,6 +803,10 @@ static umode_t queue_attr_visible(struct kobject *kobj, struct attribute *attr,
> (!q->mq_ops || !q->mq_ops->timeout))
> return 0;
>
> + if (attr == &queue_max_open_zones_entry.attr &&
> + !blk_queue_is_zoned(q))
> + return 0;
> +
> return attr->mode;
> }
>
> diff --git a/drivers/nvme/host/zns.c b/drivers/nvme/host/zns.c
> index 04e5b991c00c..3d80b9cf6bfc 100644
> --- a/drivers/nvme/host/zns.c
> +++ b/drivers/nvme/host/zns.c
> @@ -96,6 +96,7 @@ int nvme_update_zone_info(struct gendisk *disk, struct nvme_ns *ns,
>
> q->limits.zoned = BLK_ZONED_HM;
> blk_queue_flag_set(QUEUE_FLAG_ZONE_RESETALL, q);
> + blk_queue_max_open_zones(q, le32_to_cpu(id->mor) + 1);
> free_data:
> kfree(id);
> return status;
> diff --git a/drivers/scsi/sd_zbc.c b/drivers/scsi/sd_zbc.c
> index 183a20720da9..aa3564139b40 100644
> --- a/drivers/scsi/sd_zbc.c
> +++ b/drivers/scsi/sd_zbc.c
> @@ -717,6 +717,10 @@ int sd_zbc_read_zones(struct scsi_disk *sdkp, unsigned char *buf)
> /* The drive satisfies the kernel restrictions: set it up */
> blk_queue_flag_set(QUEUE_FLAG_ZONE_RESETALL, q);
> blk_queue_required_elevator_features(q, ELEVATOR_F_ZBD_SEQ_WRITE);
> + if (sdkp->zones_max_open == U32_MAX)
> + blk_queue_max_open_zones(q, 0);
> + else
> + blk_queue_max_open_zones(q, sdkp->zones_max_open);
> nr_zones = round_up(sdkp->capacity, zone_blocks) >> ilog2(zone_blocks);
>
> /* READ16/WRITE16 is mandatory for ZBC disks */
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index 8fd900998b4e..fe168abcfdda 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -520,6 +520,7 @@ struct request_queue {
> unsigned int nr_zones;
> unsigned long *conv_zones_bitmap;
> unsigned long *seq_zones_wlock;
> + unsigned int max_open_zones;
> #endif /* CONFIG_BLK_DEV_ZONED */
>
> /*
> @@ -729,6 +730,17 @@ static inline bool blk_queue_zone_is_seq(struct request_queue *q,
> return true;
> return !test_bit(blk_queue_zone_no(q, sector), q->conv_zones_bitmap);
> }
> +
> +static inline void blk_queue_max_open_zones(struct request_queue *q,
> + unsigned int max_open_zones)
> +{
> + q->max_open_zones = max_open_zones;
> +}
> +
> +static inline unsigned int queue_max_open_zones(const struct request_queue *q)
> +{
> + return q->max_open_zones;
> +}
> #else /* CONFIG_BLK_DEV_ZONED */
> static inline unsigned int blk_queue_nr_zones(struct request_queue *q)
> {
> @@ -744,6 +756,10 @@ static inline unsigned int blk_queue_zone_no(struct request_queue *q,
> {
> return 0;
> }
> +static inline unsigned int queue_max_open_zones(const struct request_queue *q)
> +{
> + return 0;
> +}
> #endif /* CONFIG_BLK_DEV_ZONED */
>
> static inline bool rq_is_sync(struct request *rq)
>
Looks good to me.
Reviewed-by: Damien Le Moal <damien.lemoal@xxxxxxx>
--
Damien Le Moal
Western Digital Research
