Re: [cpuops cmpxchg double V2 1/4] Generic support for this_cpu_cmpxchg_double

From: H. Peter Anvin
Date: Thu Jan 06 2011 - 17:06:33 EST

On 01/06/2011 12:45 PM, Christoph Lameter wrote:
> Introduce this_cpu_cmpxchg_double. this_cpu_cmpxchg_double() allows the
> comparision between two consecutive words and replaces them if there is
> a match.
> bool this_cpu_cmpxchg_double(pcp1, pcp2,
> old_word1, old_word2, new_word1, new_word2)
> this_cpu_cmpxchg_double does not return the old value (difficult since
> there are two words) but a boolean indicating if the operation was
> successful.
> The first percpu variable must be double word aligned!

I really truly hate this interface. The whole notion of passing two
pointers where only one is really used, is just painful.

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