llist: move cpu_relax after cmpxchg

llist: move cpu_relax after cmpxchg

If the first cmpxchg call succeeds, it is not necessary to use cpu_relax
before cmpxchg.  So cpu_relax in a busy loop involving cmpxchg should go
after cmpxchg instead of before that.  This patch fixes this in llist.

Signed-off-by: Huang Ying <ying.huang@intel.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <>