Re: [PATCH] block: check for max_hw_sectors underflow

[Bart Van Assche <bvanassche@xxxxxxx>]

On 5/24/24 02:57, Hannes Reinecke wrote:
> diff --git a/block/blk-settings.c b/block/blk-settings.c
> index 524cf597b2e9..0cdca702e988 100644
> --- a/block/blk-settings.c
> +++ b/block/blk-settings.c
> @@ -133,6 +133,8 @@ static int blk_validate_limits(struct queue_limits *lim)
>   		lim->max_hw_sectors = BLK_SAFE_MAX_SECTORS;
>   	if (WARN_ON_ONCE(lim->max_hw_sectors < PAGE_SECTORS))
>   		return -EINVAL;
> +	if (WARN_ON_ONCE((lim->logical_block_size >> SECTOR_SHIFT) > lim->max_hw_sectors))
> +		return -EINVAL;
>   	lim->max_hw_sectors = round_down(lim->max_hw_sectors,
>   			lim->logical_block_size >> SECTOR_SHIFT);
>   

Why is lim->max_hw_sectors checked before calling round_down() instead
of checking that round_down() returns zero?

Thanks,

Bart.