From: Scott Wood <scottw...@freescale.com>
Date: Fri, 28 Jan 2011 10:56:10 -0600
> On Fri, 28 Jan 2011 09:10:46 +0000
> David Laight <david.lai...@aculab.com> wrote:
>
>>
>> > + 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.
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