s390/atomic: implement atomic_sub_return() with atomic_add_return()
authorHeiko Carstens <heiko.carstens@de.ibm.com>
Wed, 11 Sep 2013 12:28:47 +0000 (14:28 +0200)
committerMartin Schwidefsky <schwidefsky@de.ibm.com>
Thu, 24 Oct 2013 15:16:46 +0000 (17:16 +0200)
commit86d51bc31fabd3782a99375b6848c5c667e72605
tree781b7b812c8fd4a51dbcdc238e8b90c4b3a2cbb6
parentfcd05b50fca44be3f96f8a17c5cce778669c29e7
s390/atomic: implement atomic_sub_return() with atomic_add_return()

Get rid of the own atomic_sub_return() implementation. Otherwise we can't
make use of the interlocked-access facility 1 instructions for
atomic_sub_return(), since there is no "load and subtract" instruction
available.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
arch/s390/include/asm/atomic.h