Apart from couple of nits this looks good.
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@xxxxxxx>
On 6/15/20 4:35 PM, Keith Busch wrote:
> From: Aravind Ramesh <aravind.ramesh@xxxxxxx>
>
> Allow emulation of a zoned device with a per zone capacity smaller than
> the zone size as as defined in the Zoned Namespace (ZNS) Command Set
> specification. The zone capacity defaults to the zone size if not
> specified and must be smaller than the zone size otherwise.
>
> Signed-off-by: Aravind Ramesh <aravind.ramesh@xxxxxxx>
> ---
> drivers/block/null_blk.h | 2 ++
> drivers/block/null_blk_main.c | 9 ++++++++-
> drivers/block/null_blk_zoned.c | 17 +++++++++++++++--
> 3 files changed, 25 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/block/null_blk.h b/drivers/block/null_blk.h
> index 81b311c9d781..7eadf190528c 100644
> --- a/drivers/block/null_blk.h
> +++ b/drivers/block/null_blk.h
> @@ -44,11 +44,13 @@ struct nullb_device {
> unsigned int nr_zones;
> struct blk_zone *zones;
> sector_t zone_size_sects;
> + sector_t zone_capacity_sects;
>
> unsigned long size; /* device size in MB */
> unsigned long completion_nsec; /* time in ns to complete a request */
> unsigned long cache_size; /* disk cache size in MB */
> unsigned long zone_size; /* zone size in MB if device is zoned */
> + unsigned long zone_capacity; /* zone cap in MB if device is zoned */
> unsigned int zone_nr_conv; /* number of conventional zones */
> unsigned int submit_queues; /* number of submission queues */
> unsigned int home_node; /* home node for the device */
> diff --git a/drivers/block/null_blk_main.c b/drivers/block/null_blk_main.c
> index 87b31f9ca362..54c5b5df399d 100644
> --- a/drivers/block/null_blk_main.c
> +++ b/drivers/block/null_blk_main.c
> @@ -200,6 +200,10 @@ static unsigned long g_zone_size = 256;
> module_param_named(zone_size, g_zone_size, ulong, S_IRUGO);
> MODULE_PARM_DESC(zone_size, "Zone size in MB when block device is zoned. Must be power-of-two: Default: 256");
>
> +static unsigned long g_zone_capacity;
> +module_param_named(zone_capacity, g_zone_capacity, ulong, 0444);
> +MODULE_PARM_DESC(zone_capacity, "Zone capacity in MB when block device is zoned. Can be less than or equal to zone size. Default: Zone size");
> +
> static unsigned int g_zone_nr_conv;
> module_param_named(zone_nr_conv, g_zone_nr_conv, uint, 0444);
> MODULE_PARM_DESC(zone_nr_conv, "Number of conventional zones when block device is zoned. Default: 0");
> @@ -341,6 +345,7 @@ NULLB_DEVICE_ATTR(mbps, uint, NULL);
> NULLB_DEVICE_ATTR(cache_size, ulong, NULL);
> NULLB_DEVICE_ATTR(zoned, bool, NULL);
> NULLB_DEVICE_ATTR(zone_size, ulong, NULL);
> +NULLB_DEVICE_ATTR(zone_capacity, ulong, NULL);
> NULLB_DEVICE_ATTR(zone_nr_conv, uint, NULL);
>
> static ssize_t nullb_device_power_show(struct config_item *item, char *page)
> @@ -457,6 +462,7 @@ static struct configfs_attribute *nullb_device_attrs[] = {
> &nullb_device_attr_badblocks,
> &nullb_device_attr_zoned,
> &nullb_device_attr_zone_size,
> + &nullb_device_attr_zone_capacity,
> &nullb_device_attr_zone_nr_conv,
> NULL,
> };
> @@ -510,7 +516,7 @@ nullb_group_drop_item(struct config_group *group, struct config_item *item)
>
> static ssize_t memb_group_features_show(struct config_item *item, char *page)
> {
> - return snprintf(page, PAGE_SIZE, "memory_backed,discard,bandwidth,cache,badblocks,zoned,zone_size,zone_nr_conv\n");
> + return snprintf(page, PAGE_SIZE, "memory_backed,discard,bandwidth,cache,badblocks,zoned,zone_size,zone_capacity,zone_nr_conv\n");
This line is becoming ridiculously long even for new 100 char limit.
Maybe we should do a cleanup patch for feature to string conversion.
> }
>
> CONFIGFS_ATTR_RO(memb_group_, features);
> @@ -571,6 +577,7 @@ static struct nullb_device *null_alloc_dev(void)
> dev->use_per_node_hctx = g_use_per_node_hctx;
> dev->zoned = g_zoned;
> dev->zone_size = g_zone_size;
> + dev->zone_capacity = g_zone_capacity;
> dev->zone_nr_conv = g_zone_nr_conv;
> return dev;
> }
> diff --git a/drivers/block/null_blk_zoned.c b/drivers/block/null_blk_zoned.c
> index 624aac09b005..b05832eb21b2 100644
> --- a/drivers/block/null_blk_zoned.c
> +++ b/drivers/block/null_blk_zoned.c
> @@ -28,7 +28,17 @@ int null_init_zoned_dev(struct nullb_device *dev, struct request_queue *q)
> return -EINVAL;
> }
>
> + if (!dev->zone_capacity)
> + dev->zone_capacity = dev->zone_size;
> +
> + if (dev->zone_capacity > dev->zone_size) {
> + pr_err("null_blk: zone capacity %lu more than its size %lu\n",
> + dev->zone_capacity, dev->zone_size);
> + return -EINVAL;
> + }
> +
> dev->zone_size_sects = dev->zone_size << ZONE_SIZE_SHIFT;
> + dev->zone_capacity_sects = dev->zone_capacity << ZONE_SIZE_SHIFT;
Do we really need zone_capacity_sects ? As far as I can see its is not
used into fast path, correct me if I'm wrong.
> dev->nr_zones = dev_size >>
> (SECTOR_SHIFT + ilog2(dev->zone_size_sects));
> dev->zones = kvmalloc_array(dev->nr_zones, sizeof(struct blk_zone),
> @@ -60,7 +70,7 @@ int null_init_zoned_dev(struct nullb_device *dev, struct request_queue *q)
>
> zone->start = zone->wp = sector;
> zone->len = dev->zone_size_sects;
> - zone->capacity = zone->len;
> + zone->capacity = dev->zone_capacity_sects;
We can just dev->zone_capacity << ZONE_SIZE_SHIFT here.
> zone->type = BLK_ZONE_TYPE_SEQWRITE_REQ;
> zone->cond = BLK_ZONE_COND_EMPTY;
>
> @@ -187,6 +197,9 @@ static blk_status_t null_zone_write(struct nullb_cmd *cmd, sector_t sector,
> return BLK_STS_IOERR;
> }
>
> + if (zone->wp + nr_sectors > zone->start + zone->capacity)
> + return BLK_STS_IOERR;
> +
> if (zone->cond != BLK_ZONE_COND_EXP_OPEN)
> zone->cond = BLK_ZONE_COND_IMP_OPEN;
>
> @@ -195,7 +208,7 @@ static blk_status_t null_zone_write(struct nullb_cmd *cmd, sector_t sector,
> return ret;
>
> zone->wp += nr_sectors;
> - if (zone->wp == zone->start + zone->len)
> + if (zone->wp == zone->start + zone->capacity)
> zone->cond = BLK_ZONE_COND_FULL;
> return BLK_STS_OK;
> default:
>
