locking/atomic, arch/s390: Implement atomic{,64}_fetch_{add,sub,and,or,xor}()
authorPeter Zijlstra <peterz@infradead.org>
Sun, 17 Apr 2016 23:16:05 +0000 (01:16 +0200)
committerIngo Molnar <mingo@kernel.org>
Thu, 16 Jun 2016 08:48:29 +0000 (10:48 +0200)
commit56fefbbc3f13ad8cc9f502dbc6b5c9ddc8c4395e
tree4643604e72c1ce99d08bc083a9120ee703804d1e
parenta28cc7bbe8e30ee573e1a27e704558f0862d8c6d
locking/atomic, arch/s390: 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: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.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: linux-s390@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
arch/s390/include/asm/atomic.h