[PATCH v3 06/15] block: use zone condition to determine conventional zones

[Hannes Reinecke]

On 11/4/25 02:31, Damien Le Moal wrote:
> The conv_zones_bitmap field of struct gendisk is used to define a bitmap
> to identify the conventional zones of a zoned block device. The bit for
> a zone is set in this bitmap if the zone is a conventional one, that is,
> if the zone type is BLK_ZONE_TYPE_CONVENTIONAL. For such zone, this
> always corresponds to the zone condition BLK_ZONE_COND_NOT_WP.
> In other words, conv_zones_bitmap tracks a single condition of the
> zones of a zoned block device.
> 
> In preparation for tracking more zone conditions, change
> conv_zones_bitmap into an array of zone conditions, using 1 byte per
> zone. This increases the memory usage from 1 bit per zone to 1 byte per
> zone, that is, from 16 KiB to about 100 KiB for a 30 TB SMR HDD with 256
> MiB zones. This is a trade-off to allow fast cached report zones later
> on top of this change.
> 
> Rename the conv_zones_bitmap field of struct gendisk to zones_cond. Add
> a blk_revalidate_zone_cond() function to initialize the zones_cond array
> of a disk during device scan and to update it on device revalidation.
> Move the allocation of the zones_cond array to
> disk_revalidate_zone_resources(), making sure that this array is always
> allocated, even for devices that do not need zone write plugs (zone
> resources), to ensure that bdev_zone_is_seq() can be re-implemented to
> use the zone condition array in place of the conv zones bitmap.
> 
> Finally, the function bdev_zone_is_seq() is rewritten to use a test on
> the condition of the target zone.
> 
> Signed-off-by: Damien Le Moal <dlemoal at kernel.org>
> Reviewed-by: Christoph Hellwig <hch at lst.de>
> Reviewed-by: Johannes Thumshirn <johannes.thumshirn at wdc.com>
> ---
>   block/blk-zoned.c      | 153 +++++++++++++++++++++++++++++------------
>   include/linux/blkdev.h |  37 +++-------
>   2 files changed, 117 insertions(+), 73 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare at suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
hare at suse.de                                +49 911 74053 688
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