Buf ring cleanups

[Alan Cox]

On Thu, Jul 30, 2015 at 6:34 AM, Zbigniew Bodek <zbb at semihalf.com> wrote:

> Hello,
>
> I'm writing to ensure what to do with that patch:
> https://reviews.freebsd.org/D1945
>
> It was created as a result of discussion related to this review:
> https://reviews.freebsd.org/D1833
> The patch (D1945) is still waiting to be committed. We really need fix
> for ARM in buf_ring so if someone is sure that the patch is OK then
> please commit.
>
> Thanks in advance and best regards
>


bde@, kib@, and I have been slogging through kern/, net/, and sys/
reviewing the use of memory ordering primitives and correcting problems.
We should get to buf_ring.h soon.

However, we also need to pause and update the atomic(9) man page.  It
defines the semantics of acquire and release in a way that is inconsistent
with the architectures that natively support the release consistency model,
e.g., arm64 and ia64, as well as the C11 and C++11 standards.  Lines 330
through 339 of the patch in D1945 is one example of where the incorrect
definition in the current man page has an effect.

Alan