[PATCH v2 06/28] block: Remember zone capacity when revalidating zones

Damien Le Moal
2024-03-25T04:45:06Z

In preparation for adding zone write plugging, modify
blk_revalidate_disk_zones() to get the capacity of zones of a zoned
block device. This capacity value as a number of 512B sectors is stored
in the gendisk zone_capacity field.

Given that host-managed SMR disks (including zoned UFS drives) and all
known NVMe ZNS devices have the same zone capacity for all zones
blk_revalidate_disk_zones() returns an error if different capacities are
detected for different zones.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
block/blk-zoned.c | 15 +++++++++++++++
include/linux/blkdev.h | 1 +
2 files changed, 16 insertions(+)

diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index da0f4b2a8fa0..88110a1329cd 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -438,6 +438,7 @@ struct blk_revalidate_zone_args {
unsigned long *conv_zones_bitmap;
unsigned long *seq_zones_wlock;
unsigned int nr_zones;
+ unsigned int zone_capacity;
sector_t sector;
};

@@ -500,6 +501,18 @@ static int blk_revalidate_zone_cb(struct blk_zone *zone, unsigned int idx,
if (!args->seq_zones_wlock)
return -ENOMEM;
}
+
+ /*
+ * Remember the capacity of the first sequential zone and check
+ * if it is constant for all zones.
+ */
+ if (!args->zone_capacity)
+ args->zone_capacity = zone->capacity;
+ if (zone->capacity != args->zone_capacity) {
+ pr_warn("%s: Invalid variable zone capacity\n",
+ disk->disk_name);
+ return -ENODEV;
+ }
break;
case BLK_ZONE_TYPE_SEQWRITE_PREF:
default:
@@ -597,6 +610,7 @@ int blk_revalidate_disk_zones(struct gendisk *disk,
disk->nr_zones = args.nr_zones;
swap(disk->seq_zones_wlock, args.seq_zones_wlock);
swap(disk->conv_zones_bitmap, args.conv_zones_bitmap);
+ disk->zone_capacity = args.zone_capacity;
if (update_driver_data)
update_driver_data(disk);
ret = 0;
@@ -608,6 +622,7 @@ int blk_revalidate_disk_zones(struct gendisk *disk,

kfree(args.seq_zones_wlock);
kfree(args.conv_zones_bitmap);
+
return ret;
}
EXPORT_SYMBOL_GPL(blk_revalidate_disk_zones);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 93f93f352b54..b57244ee74f0 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -191,6 +191,7 @@ struct gendisk {
* blk_mq_unfreeze_queue().
*/
unsigned int nr_zones;
+ unsigned int zone_capacity;
unsigned long *conv_zones_bitmap;
unsigned long *seq_zones_wlock;
#endif /* CONFIG_BLK_DEV_ZONED */
--
2.44.0