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Commit 1f51dee7 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

locking/atomic, arch/alpha: Implement atomic{,64}_fetch_{add,sub,and,andnot,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: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-alpha@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent b316ff78

arch/alpha/include/asm/atomic.h

+56 −9
Original line number Original line Diff line number Diff line
@@ -65,6 +65,25 @@ static inline int atomic_##op##_return(int i, atomic_t *v) \ 
	return result;							\

	return result;							\

}

}





#define ATOMIC_FETCH_OP(op, asm_op)					\

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

{									\

	long temp, result;						\

	smp_mb();							\

	__asm__ __volatile__(						\

	"1:	ldl_l %2,%1\n"						\

	"	" #asm_op " %2,%3,%0\n"					\

	"	stl_c %0,%1\n"						\

	"	beq %0,2f\n"						\

	".subsection 2\n"						\

	"2:	br 1b\n"						\

	".previous"							\

	:"=&r" (temp), "=m" (v->counter), "=&r" (result)		\

	:"Ir" (i), "m" (v->counter) : "memory");			\

	smp_mb();							\

	return result;							\

}



#define ATOMIC64_OP(op, asm_op)						\

#define ATOMIC64_OP(op, asm_op)						\

static __inline__ void atomic64_##op(long i, atomic64_t * v)		\

static __inline__ void atomic64_##op(long i, atomic64_t * v)		\

{									\

{									\
@@ -101,11 +120,32 @@ static __inline__ long atomic64_##op##_return(long i, atomic64_t * v) \ 
	return result;							\

	return result;							\

}

}





#define ATOMIC64_FETCH_OP(op, asm_op)					\

static __inline__ long atomic64_fetch_##op(long i, atomic64_t * v)	\

{									\

	long temp, result;						\

	smp_mb();							\

	__asm__ __volatile__(						\

	"1:	ldq_l %2,%1\n"						\

	"	" #asm_op " %2,%3,%0\n"					\

	"	stq_c %0,%1\n"						\

	"	beq %0,2f\n"						\

	".subsection 2\n"						\

	"2:	br 1b\n"						\

	".previous"							\

	:"=&r" (temp), "=m" (v->counter), "=&r" (result)		\

	:"Ir" (i), "m" (v->counter) : "memory");			\

	smp_mb();							\

	return result;							\

}



#define ATOMIC_OPS(op)							\

#define ATOMIC_OPS(op)							\

	ATOMIC_OP(op, op##l)						\

	ATOMIC_OP(op, op##l)						\

	ATOMIC_OP_RETURN(op, op##l)					\

	ATOMIC_OP_RETURN(op, op##l)					\

	ATOMIC_FETCH_OP(op, op##l)					\

	ATOMIC64_OP(op, op##q)						\

	ATOMIC64_OP(op, op##q)						\

	ATOMIC64_OP_RETURN(op, op##q)

	ATOMIC64_OP_RETURN(op, op##q)					\

	ATOMIC64_FETCH_OP(op, op##q)





ATOMIC_OPS(add)

ATOMIC_OPS(add)

ATOMIC_OPS(sub)

ATOMIC_OPS(sub)
@@ -113,18 +153,25 @@ ATOMIC_OPS(sub) 
#define atomic_andnot atomic_andnot

#define atomic_andnot atomic_andnot

#define atomic64_andnot atomic64_andnot

#define atomic64_andnot atomic64_andnot





ATOMIC_OP(and, and)

#define atomic_fetch_or atomic_fetch_or

ATOMIC_OP(andnot, bic)



ATOMIC_OP(or, bis)

#undef ATOMIC_OPS

ATOMIC_OP(xor, xor)

#define ATOMIC_OPS(op, asm)						\

ATOMIC64_OP(and, and)

	ATOMIC_OP(op, asm)						\

ATOMIC64_OP(andnot, bic)

	ATOMIC_FETCH_OP(op, asm)					\

ATOMIC64_OP(or, bis)

	ATOMIC64_OP(op, asm)						\

ATOMIC64_OP(xor, xor)

	ATOMIC64_FETCH_OP(op, asm)



ATOMIC_OPS(and, and)

ATOMIC_OPS(andnot, bic)

ATOMIC_OPS(or, bis)

ATOMIC_OPS(xor, xor)





#undef ATOMIC_OPS

#undef ATOMIC_OPS

#undef ATOMIC64_FETCH_OP

#undef ATOMIC64_OP_RETURN

#undef ATOMIC64_OP_RETURN

#undef ATOMIC64_OP

#undef ATOMIC64_OP

#undef ATOMIC_FETCH_OP

#undef ATOMIC_OP_RETURN

#undef ATOMIC_OP_RETURN

#undef ATOMIC_OP

#undef ATOMIC_OP