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locking/atomic, arch/sparc: Implement atomic{,64}_fetch_{add,sub,and,or,xor}()

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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>
This commit is contained in:
Peter Zijlstra
2016-04-18 01:16:04 +02:00
committed by Ingo Molnar
parent 7d9794e752
commit 3a1adb23a5
6 changed files with 109 additions and 38 deletions
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15
arch/sparc/include/asm/atomic_32.h
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@@ -20,9 +20,10 @@
#define ATOMIC_INIT(i) { (i) }
int atomic_add_return(int, atomic_t *);
void atomic_and(int, atomic_t *);
void atomic_or(int, atomic_t *);
void atomic_xor(int, atomic_t *);
int atomic_fetch_add(int, atomic_t *);
int atomic_fetch_and(int, atomic_t *);
int atomic_fetch_or(int, atomic_t *);
int atomic_fetch_xor(int, atomic_t *);
int atomic_cmpxchg(atomic_t *, int, int);
int atomic_xchg(atomic_t *, int);
int __atomic_add_unless(atomic_t *, int, int);
@@ -35,7 +36,15 @@ void atomic_set(atomic_t *, int);
#define atomic_inc(v) ((void)atomic_add_return( 1, (v)))
#define atomic_dec(v) ((void)atomic_add_return( -1, (v)))
#define atomic_fetch_or atomic_fetch_or
#define atomic_and(i, v) ((void)atomic_fetch_and((i), (v)))
#define atomic_or(i, v) ((void)atomic_fetch_or((i), (v)))
#define atomic_xor(i, v) ((void)atomic_fetch_xor((i), (v)))
#define atomic_sub_return(i, v) (atomic_add_return(-(int)(i), (v)))
#define atomic_fetch_sub(i, v) (atomic_fetch_add (-(int)(i), (v)))
#define atomic_inc_return(v) (atomic_add_return( 1, (v)))
#define atomic_dec_return(v) (atomic_add_return( -1, (v)))