[PATCH] locking/atomics: Combine the atomic_andnot() and atomic64_andnot() API definitions

[Ingo Molnar]

* Ingo Molnar <mingo@xxxxxxxxxx> wrote:

> Note that the simplest definition block is now:
> 
> #ifndef atomic_cmpxchg_relaxed
> # define atomic_cmpxchg_relaxed			atomic_cmpxchg
> # define atomic_cmpxchg_acquire			atomic_cmpxchg
> # define atomic_cmpxchg_release			atomic_cmpxchg
> #else
> # ifndef atomic_cmpxchg
> #  define atomic_cmpxchg(...)			__atomic_op_fence(atomic_cmpxchg, __VA_ARGS__)
> #  define atomic_cmpxchg_acquire(...)		__atomic_op_acquire(atomic_cmpxchg, __VA_ARGS__)
> #  define atomic_cmpxchg_release(...)		__atomic_op_release(atomic_cmpxchg, __VA_ARGS__)
> # endif
> #endif
> 
> ... which is very readable!
> 
> The total linecount reduction of the two patches is pretty significant as well:
> 
>  include/linux/atomic.h | 1063 ++++++++++++++++--------------------------------
>  1 file changed, 343 insertions(+), 720 deletions(-)

BTW., I noticed two asymmetries while cleaning up this code:

==============>

#ifdef atomic_andnot

#ifndef atomic_fetch_andnot_relaxed
# define atomic_fetch_andnot_relaxed            atomic_fetch_andnot
# define atomic_fetch_andnot_acquire            atomic_fetch_andnot
# define atomic_fetch_andnot_release            atomic_fetch_andnot
#else
# ifndef atomic_fetch_andnot
#  define atomic_fetch_andnot(...)              __atomic_op_fence(atomic_fetch_andnot, __VA_ARGS__)
#  define atomic_fetch_andnot_acquire(...)      __atomic_op_acquire(atomic_fetch_andnot, __VA_ARGS__)
#  define atomic_fetch_andnot_release(...)      __atomic_op_release(atomic_fetch_andnot, __VA_ARGS__)
# endif
#endif

#endif /* atomic_andnot */

...

#ifdef atomic64_andnot

#ifndef atomic64_fetch_andnot_relaxed
# define atomic64_fetch_andnot_relaxed          atomic64_fetch_andnot
# define atomic64_fetch_andnot_acquire          atomic64_fetch_andnot
# define atomic64_fetch_andnot_release          atomic64_fetch_andnot
#else
# ifndef atomic64_fetch_andnot
#  define atomic64_fetch_andnot(...)            __atomic_op_fence(atomic64_fetch_andnot, __VA_ARGS__)
#  define atomic64_fetch_andnot_acquire(...)    __atomic_op_acquire(atomic64_fetch_andnot, __VA_ARGS__)
#  define atomic64_fetch_andnot_release(...)    __atomic_op_release(atomic64_fetch_andnot, __VA_ARGS__)
# endif
#endif

#endif /* atomic64_andnot */

<==============

Why do these two API groups have an outer condition, i.e.:

 #ifdef atomic_andnot
 ...
 #endif /* atomic_andnot */
 ...
 #ifdef atomic64_andnot
 ...
 #endif /* atomic64_andnot */

because the base APIs themselves are optional and have a default implementation:

 #ifndef atomic_andnot
 ...
 #endif
 ...
 #ifndef atomic64_andnot
 ...
 #endif

I think it's overall cleaner if we combine them into continous blocks, defining 
all variants of an API group in a single place:

 #ifdef atomic_andnot
 #else
 #endif

etc.

The patch below implements this.

Thanks,

	Ingo

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