RE: [PATCH] mlx4_en: fix transmit of packages when blue frame isenabled

=20

 static void mlx4_bf_copy(unsigned long *dst, unsigned long *src,

unsigned bytecnt) {

+	int i;
+	__le32 *psrc =3D (__le32 *)src;
+
+	/*
+	 * the buffer is already in big endian. For little endian

machines that's

+	 * fine. For big endain machines we must swap since the chipset

swaps again

+	 */
+	for (i =3D 0; i < bytecnt / 4; ++i)
+		psrc[i] =3D le32_to_cpu(psrc[i]);
+
 	__iowrite64_copy(dst, src, bytecnt / 8);
 }

That code looks 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....