Re: [PATCH v2 08/13] xen/bitops: Implement ffsl() in common logic

[Jan Beulich <jbeulich@suse.com>]

On 24.05.2024 22:03, Andrew Cooper wrote:
> Just like ffs() in the previous changes.  Express the upper bound of the
> testing in terms of BITS_PER_LONG as it varies between architectures.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

Reviewed-by: Jan Beulich <jbeulich@suse.com>

> @@ -458,6 +441,24 @@ static always_inline unsigned int arch_ffs(unsigned int x)
>  }
>  #define arch_ffs arch_ffs
>  
> +static always_inline unsigned int arch_ffsl(unsigned long x)
> +{
> +    unsigned int r;
> +
> +    /* See arch_ffs() for safety discussions. */
> +    if ( __builtin_constant_p(x > 0) && x > 0 )

See remark on arch_ffs() for possible slight reduction of code.

Jan