Re: [PATCH] ublk: use global index for reported zones

[Ming Lei]

On Tue, Sep 29, 2026 at 03:00:12PM +0800, lirongqing wrote:
> From: Li RongQing <lirongqing@xxxxxxxxx>
> 
> ublk_report_zones() may split a zone report into multiple requests when
> the number of zones exceeds the temporary buffer capacity. The index
> passed to disk_report_zone() must refer to the zone position in the
> whole report, rather than the position within the current request.
> 
> Currently, the per-request loop index is used as the callback index,
> causing each chunk after the first one to restart from zero. This can
> make userspace callbacks receive duplicate zone indices and may result
> in blk_revalidate_disk_zones() updating incorrect entries in its zone
> state array.
> 
> Use the number of zones already reported as the base index for each
> request so that zone indices remain continuous across all chunks.
> 
> Fixes: 29802d7ca33b ("ublk: enable zoned storage support")
> Signed-off-by: Li RongQing <lirongqing@xxxxxxxxx>
> ---
>  drivers/block/ublk_drv.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
> index 66eb55e..007e703 100644
> --- a/drivers/block/ublk_drv.c
> +++ b/drivers/block/ublk_drv.c
> @@ -649,6 +649,7 @@ static int ublk_report_zones(struct gendisk *disk, sector_t sector,
>  		unsigned int remaining_zones = nr_zones - done_zones;
>  		unsigned int zones_in_request =
>  			min_t(unsigned int, remaining_zones, max_zones_per_request);
> +		unsigned int batch_start = done_zones;
>  		struct request *req;
>  		struct ublk_zoned_report_desc desc;
>  		blk_status_t status;
> @@ -687,7 +688,7 @@ static int ublk_report_zones(struct gendisk *disk, sector_t sector,
>  			if (!zone->len)
>  				break;
>  
> -			ret = disk_report_zone(disk, zone, i, args);
> +			ret = disk_report_zone(disk, zone, batch_start + i, args);

`done_zones` can be passed directly, then we can save one local variable,
otherwise, this patch looks fine:

Reviewed-by: Ming Lei <tom.leiming@xxxxxxxxx>


Thanks,
Ming