]> git.baikalelectronics.ru Git - kernel.git/commit
s390/barrier: remove unnecessary serialization in atomics and bitops
authorMartin Schwidefsky <schwidefsky@de.ibm.com>
Mon, 28 Sep 2015 13:27:26 +0000 (15:27 +0200)
committerMartin Schwidefsky <schwidefsky@de.ibm.com>
Wed, 14 Oct 2015 12:32:07 +0000 (14:32 +0200)
commit6aaae8729ba476cc7a8bb41d06857f852b8cd649
tree5fa860d7cbf09ccc0d3096d5986867b5bfc6b86f
parent1e041103f16484f5578ab05432580f4fa6163513
s390/barrier: remove unnecessary serialization in atomics and bitops

The principles of operation states reads are in order, writes are in
order, writes can be reordered after reads, but no reads can be
reordered after writes.

The atomic and bitops variantes for z196 use the interlocked-access
facility instructions with a memory barrier before and after the
instruction. Because of the memory ordering the first barrier is
unnecessary and can be removed.

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