From 0c074cbc33091dd69fe70ec27474d228c3184860 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 18 Apr 2016 01:16:08 +0200 Subject: 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: Peter Zijlstra (Intel) Cc: Andrew Morton Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Yoshinori Sato Cc: linux-arch@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: uclinux-h8-devel@lists.sourceforge.jp Signed-off-by: Ingo Molnar --- arch/h8300/include/asm/atomic.h | 31 +++++++++++++++++++++++++------ 1 file changed, 25 insertions(+), 6 deletions(-) (limited to 'arch') diff --git a/arch/h8300/include/asm/atomic.h b/arch/h8300/include/asm/atomic.h index 4435a445ae7e..0961b618bdde 100644 --- a/arch/h8300/include/asm/atomic.h +++ b/arch/h8300/include/asm/atomic.h @@ -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) -- cgit