locking/atomic, arch/blackfin: 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: Steven Miao <realmz6@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: adi-buildroot-devel@lists.sourceforge.net
Cc: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra
2016-04-18 01:16:08 +02:00
committed by Ingo Molnar
parent 1a6eafacd4
commit e87fc0ec07
3 changed files with 40 additions and 12 deletions

View File

@@ -84,6 +84,7 @@ EXPORT_SYMBOL(insl_16);
#ifdef CONFIG_SMP
EXPORT_SYMBOL(__raw_atomic_add_asm);
EXPORT_SYMBOL(__raw_atomic_xadd_asm);
EXPORT_SYMBOL(__raw_atomic_and_asm);
EXPORT_SYMBOL(__raw_atomic_or_asm);
EXPORT_SYMBOL(__raw_atomic_xor_asm);