Messages in this thread | | | Subject | Re: [RFC] should VM_BUG_ON(cond) really evaluate cond | From | Ben Hutchings <> | Date | Fri, 28 Oct 2011 04:29:26 +0100 |
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On Fri, 2011-10-28 at 04:52 +0200, Eric Dumazet wrote: > Le vendredi 28 octobre 2011 à 02:44 +0100, Ben Hutchings a écrit : > > > Whether or not it needs to provide any ordering guarantee, atomic_read() > > must never read more than once, and I think that requires the volatile > > qualification. It might be clearer to use the ACCESS_ONCE macro, > > however. > > > > Where this requirement comes from ?
That is the conventional behaviour of 'atomic' operations, and callers may depend on it.
> Maybe then introduce atomic_read_once() for users really needing it :) > > ACCESS_ONCE will force the read/move instruction I try to avoid :( [...]
I'm sure you can find some other way to avoid it.
Ben.
-- Ben Hutchings, Staff Engineer, Solarflare Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked.
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