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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: Peter 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: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2016-04-18 01:16:08 +02:00 committed by Ingo Molnar
parent d9c7302816
commit 0c074cbc33
1 changed files with 25 additions and 6 deletions
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31
arch/h8300/include/asm/atomic.h
View File

@ -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)