Re: [PATCH] m68k: merge the mmu and non-mmu versions of checksum.h

[Christoph Hellwig <hch@infradead.org>]

On Wed, Jun 17, 2009 at 05:11:15PM +1000, Greg Ungerer wrote:
> +#ifdef CONFIG_MMU
>  /*
>   *	This is a version of ip_compute_csum() optimized for IP headers,
>   *	which always checksum on 4 octet boundaries.
> @@ -59,6 +61,9 @@ static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
>  		 : "memory");
>  	return (__force __sum16)~sum;
>  }
> +#else
> +__sum16 ip_fast_csum(const void *iph, unsigned int ihl);
> +#endif

Any good reason this is inline for all mmu processors and out of line
for nommu, independent of the actual cpu variant?

>  static inline __sum16 csum_fold(__wsum sum)
>  {
>  	unsigned int tmp = (__force u32)sum;
> +#ifdef CONFIG_COLDFIRE
> +	tmp = (tmp & 0xffff) + (tmp >> 16);
> +	tmp = (tmp & 0xffff) + (tmp >> 16);
> +	return (__force __sum16)~tmp;
> +#else
>  	__asm__("swap %1\n\t"
>  		"addw %1, %0\n\t"
>  		"clrw %1\n\t"
> @@ -74,6 +84,7 @@ static inline __sum16 csum_fold(__wsum sum)
>  		: "=&d" (sum), "=&d" (tmp)
>  		: "0" (sum), "1" (tmp));
>  	return (__force __sum16)~sum;
> +#endif
>  }

I think this would be cleaner by having totally separate functions
for both cases, e.g.

#ifdef CONFIG_COLDFIRE
static inline __sum16 csum_fold(__wsum sum)
{
	unsigned int tmp = (__force u32)sum;

	tmp = (tmp & 0xffff) + (tmp >> 16);
	tmp = (tmp & 0xffff) + (tmp >> 16);

	return (__force __sum16)~tmp;
}
#else
...
#endif