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| author | Peter Zijlstra <peterz@infradead.org> | 2016-04-18 01:16:04 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-06-16 10:48:30 +0200 |
| commit | 3a1adb23a52c920304239efff377d3bc967febc2 (patch) | |
| tree | 63383d193b7a7adaec40939daac2cdd22326108a /arch/sparc/lib/atomic32.c | |
| parent | 7d9794e7523798e1b9422ad9f4e4d808ae5d5932 (diff) | |
| download | linux-3a1adb23a52c920304239efff377d3bc967febc2.tar.bz2 | |
locking/atomic, arch/sparc: Implement atomic{,64}_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>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: James Y Knight <jyknight@google.com>
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: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: sparclinux@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/sparc/lib/atomic32.c')
| -rw-r--r-- | arch/sparc/lib/atomic32.c | 29 |
1 files changed, 17 insertions, 12 deletions
diff --git a/arch/sparc/lib/atomic32.c b/arch/sparc/lib/atomic32.c index b9d63c0a7aab..2c373329d5cb 100644 --- a/arch/sparc/lib/atomic32.c +++ b/arch/sparc/lib/atomic32.c @@ -27,39 +27,44 @@ static DEFINE_SPINLOCK(dummy); #endif /* SMP */ -#define ATOMIC_OP_RETURN(op, c_op) \ -int atomic_##op##_return(int i, atomic_t *v) \ +#define ATOMIC_FETCH_OP(op, c_op) \ +int atomic_fetch_##op(int i, atomic_t *v) \ { \ int ret; \ unsigned long flags; \ spin_lock_irqsave(ATOMIC_HASH(v), flags); \ \ - ret = (v->counter c_op i); \ + ret = v->counter; \ + v->counter c_op i; \ \ spin_unlock_irqrestore(ATOMIC_HASH(v), flags); \ return ret; \ } \ -EXPORT_SYMBOL(atomic_##op##_return); +EXPORT_SYMBOL(atomic_fetch_##op); -#define ATOMIC_OP(op, c_op) \ -void atomic_##op(int i, atomic_t *v) \ +#define ATOMIC_OP_RETURN(op, c_op) \ +int atomic_##op##_return(int i, atomic_t *v) \ { \ + int ret; \ unsigned long flags; \ spin_lock_irqsave(ATOMIC_HASH(v), flags); \ \ - v->counter c_op i; \ + ret = (v->counter c_op i); \ \ spin_unlock_irqrestore(ATOMIC_HASH(v), flags); \ + return ret; \ } \ -EXPORT_SYMBOL(atomic_##op); +EXPORT_SYMBOL(atomic_##op##_return); ATOMIC_OP_RETURN(add, +=) -ATOMIC_OP(and, &=) -ATOMIC_OP(or, |=) -ATOMIC_OP(xor, ^=) +ATOMIC_FETCH_OP(add, +=) +ATOMIC_FETCH_OP(and, &=) +ATOMIC_FETCH_OP(or, |=) +ATOMIC_FETCH_OP(xor, ^=) + +#undef ATOMIC_FETCH_OP #undef ATOMIC_OP_RETURN -#undef ATOMIC_OP int atomic_xchg(atomic_t *v, int new) { |