Re: [PATCH 17/27] add generic lib/checksum.c

[Arnd Bergmann]

On Friday 01 May 2009, Russell King wrote:
> Since when has 'memcpy' been valid from user addresses?

It's an artifact from the microblaze code, I found it after
submitting the patches when running sparse over it (yes, I
know I should do these things in a different order).

The s390 version seems to get this right, so I'll use this:

static inline __wsum
csum_partial_copy_from_user(const void __user *src, void *dst,
                                          int len, __wsum sum,
                                          int *err_ptr)
{
	int missing;

	missing = copy_from_user(dst, src, len);
	if (missing) {
		memset(dst + len - missing, 0, missing);
		*err_ptr = -EFAULT;
	}

	return csum_partial(dst, len, sum);
}

On microblaze, the old code was only correct for NOMMU.

Thanks,

	Arnd <><
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