locking/atomic, arch/arm: Implement atomic{,64}_fetch_{add,sub,and,andnot,or,xor...
authorPeter Zijlstra <peterz@infradead.org>
Sun, 17 Apr 2016 23:10:52 +0000 (01:10 +0200)
committerIngo Molnar <mingo@kernel.org>
Thu, 16 Jun 2016 08:48:20 +0000 (10:48 +0200)
commit6da068c1beba684b2a0dbf43a07b0529edd9e959
treedcc2b7f55837ea2981ba460f3cc7de2f5ec379eb
parentfbffe892e5253dd02c016c59a9d792eafe9d53e1
locking/atomic, arch/arm: Implement atomic{,64}_fetch_{add,sub,and,andnot,or,xor}{,_relaxed,_acquire,_release}()

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: Will Deacon <will.deacon@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
arch/arm/include/asm/atomic.h