Re: [PATCH 3/8] scsi: sd_zbc: Verify that the zone size is a power of two

[Damien Le Moal <damien.lemoal@opensource.wdc.com>]

On 4/16/22 05:17, Bart Van Assche wrote:
> The following check in sd_zbc_cmnd_checks() can only work correctly if
> the zone size is a power of two:
> 
> 	if (sector & (sd_zbc_zone_sectors(sdkp) - 1))
> 		/* Unaligned request */
> 		return BLK_STS_IOERR;
> 
> Hence this patch that verifies that the zone size is a power of two.
> 
> Signed-off-by: Bart Van Assche <bvanassche@acm.org>

Note that this is already checked in blk_revalidate_disk_zones(), but it
does not hurt to add the check.

Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>

> ---
>  drivers/scsi/sd_zbc.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/scsi/sd_zbc.c b/drivers/scsi/sd_zbc.c
> index d0275855b16c..c1f295859b27 100644
> --- a/drivers/scsi/sd_zbc.c
> +++ b/drivers/scsi/sd_zbc.c
> @@ -666,6 +666,13 @@ static int sd_zbc_check_capacity(struct scsi_disk *sdkp, unsigned char *buf,
>  
>  	*zblocks = zone_blocks;
>  
> +	if (!is_power_of_2(*zblocks)) {
> +		sd_printk(KERN_ERR, sdkp,
> +			  "Zone size %llu is not a power of two.\n",
> +			  zone_blocks);
> +		return -EINVAL;
> +	}
> +
>  	return 0;
>  }
>  


-- 
Damien Le Moal
Western Digital Research