block: add max_open_zones to blk-sysfs

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@wdc.com>
Reviewed-by: Javier González <javier@javigon.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/Documentation/ABI/testing/sysfs-block b/Documentation/ABI/testing/sysfs-block
index ed8c14f161ee3cbc2bb21760ccd1ff9b9ea4bb9a..f151d9cf90dea0a9d09ee2ac7474f6d32d819570 100644 (file)
--- a/Documentation/ABI/testing/sysfs-block
+++ b/Documentation/ABI/testing/sysfs-block
@@ -273,6 +273,15 @@ Description:
                device ("host-aware" or "host-managed" zone model). For regular
                block devices, the value is always 0.
 
+What:          /sys/block/<disk>/queue/max_open_zones
+Date:          July 2020
+Contact:       Niklas Cassel <niklas.cassel@wdc.com>
+Description:
+               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.
+
 What:          /sys/block/<disk>/queue/chunk_sectors
 Date:          September 2016
 Contact:       Hannes Reinecke <hare@suse.com>

diff --git a/Documentation/block/queue-sysfs.rst b/Documentation/block/queue-sysfs.rst
index 6a8513af9201caf358d7446b28cc598bab9174e4..f01cf8530ae4fd9a459a675f44ea2792885fe88a 100644 (file)
--- 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 be67952e7be229ed333c5089f556ff444a72f739..414f04579d770e25eafb7020b635f69fdf7cc9f7 100644 (file)
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -306,6 +306,11 @@ 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) |
@@ -668,6 +673,11 @@ 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,
@@ -766,6 +776,7 @@ 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,
@@ -793,6 +804,10 @@ 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 04e5b991c00cd12aadb000330c70ac162ac21d86..3d80b9cf6bfc1c9f2976a99a574fe2eafeb97e51 100644 (file)
--- 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 183a20720da9f4e6d97fb88bd3997f846a0e68f2..aa3564139b40a79e2c8fe2504a9c3c900edbed4c 100644 (file)
--- 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 de7adc59b993533ed6118552aaa6966110d207e3..c8beb8bbdb08285c27409b5a0ed3231d0d1aa5dc 100644 (file)
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -513,6 +513,7 @@ 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 */
 
        /*
@@ -722,6 +723,17 @@ 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)
 {
@@ -737,6 +749,10 @@ 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)
@@ -1519,6 +1535,15 @@ static inline sector_t bdev_zone_sectors(struct block_device *bdev)
        return 0;
 }
 
+static inline unsigned int bdev_max_open_zones(struct block_device *bdev)
+{
+       struct request_queue *q = bdev_get_queue(bdev);
+
+       if (q)
+               return queue_max_open_zones(q);
+       return 0;
+}
+
 static inline int queue_dma_alignment(const struct request_queue *q)
 {
        return q ? q->dma_alignment : 511;