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Commit 0c074cbc authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
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locking/atomic, arch/h8300: Implement atomic_fetch_{add,sub,and,or,xor}() 



Implement FETCH-OP atomic primitives, these are very similar to the
existing OP-RETURN primitives we already have, except they return the
value of the atomic variable _before_ modification.

This is especially useful for irreversible operations -- such as
bitops (because it becomes impossible to reconstruct the state prior
to modification).

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: uclinux-h8-devel@lists.sourceforge.jp
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent d9c73028

arch/h8300/include/asm/atomic.h

+25 −6
Original line number Diff line number Diff line
@@ -28,6 +28,19 @@ static inline int atomic_##op##_return(int i, atomic_t *v) \ 
	return ret;						\

}



#define ATOMIC_FETCH_OP(op, c_op)				\

static inline int atomic_fetch_##op(int i, atomic_t *v)		\

{								\

	h8300flags flags;					\

	int ret;						\

								\

	flags = arch_local_irq_save();				\

	ret = v->counter;					\

	v->counter c_op i;					\

	arch_local_irq_restore(flags);				\

	return ret;						\

}



#define ATOMIC_OP(op, c_op)					\

static inline void atomic_##op(int i, atomic_t *v)		\

{								\
@@ -41,17 +54,23 @@ static inline void atomic_##op(int i, atomic_t *v) \ 
ATOMIC_OP_RETURN(add, +=)

ATOMIC_OP_RETURN(sub, -=)



ATOMIC_OP(and, &=)

ATOMIC_OP(or,  |=)

ATOMIC_OP(xor, ^=)

#define atomic_fetch_or atomic_fetch_or



#define ATOMIC_OPS(op, c_op)					\

	ATOMIC_OP(op, c_op)					\

	ATOMIC_FETCH_OP(op, c_op)



ATOMIC_OPS(and, &=)

ATOMIC_OPS(or,  |=)

ATOMIC_OPS(xor, ^=)

ATOMIC_OPS(add, +=)

ATOMIC_OPS(sub, -=)



#undef ATOMIC_OPS

#undef ATOMIC_OP_RETURN

#undef ATOMIC_OP



#define atomic_add(i, v)		(void)atomic_add_return(i, v)

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



#define atomic_sub(i, v)		(void)atomic_sub_return(i, v)

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



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