Re: [PATCH v2 1/7] atomics: add acquire/release/relaxed variants of some atomic operations

Will Deacon
2015-07-17T17:30:53Z

On Fri, Jul 17, 2015 at 06:19:54PM +0100, Waiman Long wrote:
> On 07/17/2015 05:40 AM, Will Deacon wrote:
> > On Fri, Jul 17, 2015 at 01:07:28AM +0100, Waiman Long wrote:
> >> I have a minor nit. The atomic_add_return block is repeated with
> >> "s/atomic_add_return/.../". Perhaps some more comments to delineate the
> >> blocks more visibly will make this patch easier to read.
> > Yeah, I agree that it's pretty hard going, but I don't have any great
> > suggestions to solve that. I could add an extra blank line + comment
> > before the start of each section, if you like? Example snippet below.
> >
> > Will
> >
> > --->8
> >
> > [...]
> > #endif /* atomic_sub_return_relaxed */
> >
> >
> > /* atomic_xchg_relaxed */
> > #ifndef atomic_xchg_relaxed
> > #define atomic_xchg_relaxed atomic_xchg
> > #define atomic_xchg_acquire atomic_xchg
> > #define atomic_xchg_release atomic_xchg
> >
> > #else /* atomic_xchg_relaxed */
> >
> > #ifndef atomic_xchg_acquire
> > #define atomic_xchg_acquire(...) \
> > __atomic_op_acquire(int, atomic_xchg, __VA_ARGS__)
> > #endif
> >
> > #ifndef atomic_xchg_release
> > #define atomic_xchg_release(...) \
> > __atomic_op_release(int, atomic_xchg, __VA_ARGS__)
> > #endif
> >
> > #ifndef atomic_xchg
> > #define atomic_xchg(...) \
> > __atomic_op_fence(int, atomic_xchg, __VA_ARGS__)
> > #endif
> > #endif /* atomic_xchg_relaxed */
> >
> >
> > /* atomic_cmpxchg_relaxed */
> > [...]
> Something like
>
> /* BEGIN atomc_xchg_relax */
> ...
> /* END atomic_xchg_relax */
>
> may help.
>
> Alternatively, I sometimes add a line separator like
>
> /*===================[ atomic_xchg_relax ]====================*/

Hmm, I think we're straying into cosmetic preferences here and I can
imagine some people taking objection to the above, especially as they
don't appear to be in common use in mainline.

Will