Re: [PATCH 12/13] xfs: make the calculation generic in xfs_sb_validate_fsb_count()

[Matthew Wilcox <willy@xxxxxxxxxxxxx>]

On Mon, Feb 26, 2024 at 10:49:35AM +0100, Pankaj Raghav (Samsung) wrote:
> +	if (check_mul_overflow(nblocks, (1 << sbp->sb_blocklog), &bytes))

Why would you not use check_shl_overflow()?

> +		return -EFBIG;
> +
> +	mapping_count = bytes >> PAGE_SHIFT;
>  	/* Limited by ULONG_MAX of page cache index */
> -	if (nblocks >> (PAGE_SHIFT - sbp->sb_blocklog) > ULONG_MAX)
> +	if (mapping_count > ULONG_MAX)
>  		return -EFBIG;
>  	return 0;
>  }
> -- 
> 2.43.0
>