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Commit a82e6238 authored by Will Deacon's avatar Will Deacon
Browse files

arm64: atomics: tidy up common atomic{,64}_* macros 



The common (i.e. identical for ll/sc and lse) atomic macros in atomic.h
are needlessley different for atomic_t and atomic64_t.

This patch tidies up the definitions to make them consistent across the
two atomic types and factors out common code such as the add_unless
implementation based on cmpxchg.

Reviewed-by: default avatarSteve Capper <steve.capper@arm.com>
Reviewed-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent 4e39715f

arch/arm64/include/asm/atomic.h

+40 −59
Original line number Diff line number Diff line
@@ -26,8 +26,6 @@ 
#include <asm/barrier.h>

#include <asm/lse.h>



#define ATOMIC_INIT(i)	{ (i) }



#ifdef __KERNEL__



#define __ARM64_IN_ATOMIC_IMPL
@@ -42,71 +40,54 @@ 


#include <asm/cmpxchg.h>



/*

 * On ARM, ordinary assignment (str instruction) doesn't clear the local

 * strex/ldrex monitor on some implementations. The reason we can use it for

 * atomic_set() is the clrex or dummy strex done on every exception return.

 */

#define atomic_read(v)	ACCESS_ONCE((v)->counter)

#define atomic_set(v,i)	(((v)->counter) = (i))



#define atomic_xchg(v, new) (xchg(&((v)->counter), new))



static inline int __atomic_add_unless(atomic_t *v, int a, int u)

{

	int c, old;



	c = atomic_read(v);

	while (c != u && (old = atomic_cmpxchg((v), c, c + a)) != c)

		c = old;

	return c;

}



#define atomic_inc(v)		atomic_add(1, v)

#define atomic_dec(v)		atomic_sub(1, v)



#define atomic_inc_and_test(v)	(atomic_add_return(1, v) == 0)

#define atomic_dec_and_test(v)	(atomic_sub_return(1, v) == 0)

#define atomic_inc_return(v)    (atomic_add_return(1, v))

#define atomic_dec_return(v)    (atomic_sub_return(1, v))

#define atomic_sub_and_test(i, v) (atomic_sub_return(i, v) == 0)

#define ___atomic_add_unless(v, a, u, sfx)				\

({									\

	typeof((v)->counter) c, old;					\

									\

	c = atomic##sfx##_read(v);					\

	while (c != (u) &&						\

	      (old = atomic##sfx##_cmpxchg((v), c, c + (a))) != c)	\

		c = old;						\

	c;								\

 })



#define atomic_add_negative(i,v) (atomic_add_return(i, v) < 0)

#define ATOMIC_INIT(i)	{ (i) }



#define atomic_read(v)			READ_ONCE((v)->counter)

#define atomic_set(v, i)		(((v)->counter) = (i))

#define atomic_xchg(v, new)		xchg(&((v)->counter), (new))



#define atomic_inc(v)			atomic_add(1, (v))

#define atomic_dec(v)			atomic_sub(1, (v))

#define atomic_inc_return(v)		atomic_add_return(1, (v))

#define atomic_dec_return(v)		atomic_sub_return(1, (v))

#define atomic_inc_and_test(v)		(atomic_inc_return(v) == 0)

#define atomic_dec_and_test(v)		(atomic_dec_return(v) == 0)

#define atomic_sub_and_test(i, v)	(atomic_sub_return((i), (v)) == 0)

#define atomic_add_negative(i, v)	(atomic_add_return((i), (v)) < 0)

#define __atomic_add_unless(v, a, u)	___atomic_add_unless(v, a, u,)

#define atomic_andnot			atomic_andnot



/*

 * 64-bit atomic operations.

 */

#define ATOMIC64_INIT(i) { (i) }



#define atomic64_read(v)	ACCESS_ONCE((v)->counter)

#define atomic64_set(v,i)	(((v)->counter) = (i))



#define atomic64_xchg(v, new) (xchg(&((v)->counter), new))



static inline int atomic64_add_unless(atomic64_t *v, long a, long u)

{

	long c, old;



	c = atomic64_read(v);

	while (c != u && (old = atomic64_cmpxchg((v), c, c + a)) != c)

		c = old;



	return c != u;

}



#define atomic64_add_negative(a, v)	(atomic64_add_return((a), (v)) < 0)

#define atomic64_inc(v)			atomic64_add(1LL, (v))

#define atomic64_inc_return(v)		atomic64_add_return(1LL, (v))

#define ATOMIC64_INIT			ATOMIC_INIT

#define atomic64_read			atomic_read

#define atomic64_set			atomic_set

#define atomic64_xchg			atomic_xchg



#define atomic64_inc(v)			atomic64_add(1, (v))

#define atomic64_dec(v)			atomic64_sub(1, (v))

#define atomic64_inc_return(v)		atomic64_add_return(1, (v))

#define atomic64_dec_return(v)		atomic64_sub_return(1, (v))

#define atomic64_inc_and_test(v)	(atomic64_inc_return(v) == 0)

#define atomic64_sub_and_test(a, v)	(atomic64_sub_return((a), (v)) == 0)

#define atomic64_dec(v)			atomic64_sub(1LL, (v))

#define atomic64_dec_return(v)		atomic64_sub_return(1LL, (v))

#define atomic64_dec_and_test(v)	(atomic64_dec_return((v)) == 0)

#define atomic64_inc_not_zero(v)	atomic64_add_unless((v), 1LL, 0LL)



#define atomic64_dec_and_test(v)	(atomic64_dec_return(v) == 0)

#define atomic64_sub_and_test(i, v)	(atomic64_sub_return((i), (v)) == 0)

#define atomic64_add_negative(i, v)	(atomic64_add_return((i), (v)) < 0)

#define atomic64_add_unless(v, a, u)	(___atomic_add_unless(v, a, u, 64) != u)

#define atomic64_andnot			atomic64_andnot



#define atomic64_inc_not_zero(v)	atomic64_add_unless((v), 1, 0)



#endif

#endif