Re: [PATCH 1/7] atomic: Export fetch_or()

[Peter Zijlstra]

On Tue, Nov 24, 2015 at 10:19:52PM +0100, Frederic Weisbecker wrote:
> Also note that or_return() means that you first do OR and then return the new value.

Yes, that's useless. OR is an irreversible operator, which means
or_return() looses data. You can never say if a bit included in the
mask was set before.

You really must have fetch_or().
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/