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| author | Peter Zijlstra <peterz@infradead.org> | 2016-04-18 01:16:08 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-06-16 10:48:24 +0200 |
| commit | 0c074cbc33091dd69fe70ec27474d228c3184860 (patch) | |
| tree | 24f529cc54a3133c84aa96d3d325cb983c89cdf4 /arch/h8300/include | |
| parent | d9c730281617e55ca470e66f8e9d7d3f5f420fec (diff) | |
| download | lwn-0c074cbc33091dd69fe70ec27474d228c3184860.tar.gz lwn-0c074cbc33091dd69fe70ec27474d228c3184860.zip | |
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/include')
| -rw-r--r-- | arch/h8300/include/asm/atomic.h | 31 |
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) |