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authorPeter Zijlstra <peterz@infradead.org>2016-04-18 01:16:08 +0200
committerIngo Molnar <mingo@kernel.org>2016-06-16 10:48:24 +0200
commit0c074cbc33091dd69fe70ec27474d228c3184860 (patch)
tree24f529cc54a3133c84aa96d3d325cb983c89cdf4 /arch/h8300
parentd9c730281617e55ca470e66f8e9d7d3f5f420fec (diff)
downloadlinux-0c074cbc33091dd69fe70ec27474d228c3184860.tar.bz2
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>
Diffstat (limited to 'arch/h8300')
-rw-r--r--arch/h8300/include/asm/atomic.h31
1 files changed, 25 insertions, 6 deletions
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)