On Thu, 2011-10-06 at 15:10 +0100, David Laight wrote:

horrid...
1) I'm not sure the caller expects the buffer to be corrupted.
2) It contains a lot of memory cycles.
3) It looked from the calls that this code is copying descriptors,
   so the transfer length is probably 1 or 2 words - so the loop
   is inefficient.
4) ppc doesn't have a fast byteswap instruction (very new gcc might
   use the byteswapping memery access for the le32_to_cpu() though),
   so it would be better getting the byteswap done inside
   __iowrite64_copy() - since that is probably requesting a byteswap
   anyway.
OTOH I'm not at all clear about the 64bit xfers....

And it's just plain wrong anyway. You should never have to byteswap a
copy.

Ben.