From: Scott Wood <redacted>
Date: Fri, 28 Jan 2011 10:56:10 -0600

On Fri, 28 Jan 2011 09:10:46 +0000
David Laight [off-list ref] wrote:

quoted

quoted

+		if (unlikely(gfar_has_errata(priv, GFAR_ERRATA_12)
+			     && ((unsigned long)fcb % 0x20) > 0x18)) {

You need to check the generated code, but I think you need:

    if (unlikely(gfar_has_errata(priv, GFAR_ERRATA_12))
	     && unlikely(((unsigned long)fcb % 0x20) > 0x18))

ie unlikely() around both the primitive comparisons.

Is the first condition actually unlikely?  If you've got affected
hardware, you'll hit it every time.

If packets with the problematic alignment are rare, seems like it'd be
better to check that first.

In cases like this gfar_has_errata() case, better to leave it's
likelyhood unmarked.

And yes, since it's cheaper, checking the alignment should be done
first.