Using atomic64_xchg() instead of atomic64_read() and
atomic64_set().
Signed-off-by: NXiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Reviewed-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <4B1F19DC.90204@cn.fujitsu.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>