stop_machine: Clean up the usage of the preemption counter in cpu_stopper_thread()

1. Change this code to use preempt_count_inc/preempt_count_dec; this way
   it works even if CONFIG_PREEMPT_COUNT=n, and we avoid the unnecessary
   __preempt_schedule() check (stop_sched_class is not preemptible).

   And this makes clear that we only want to make preempt_count() != 0
   for __might_sleep() / schedule_debug().

2. Change WARN_ONCE() to use %pf to print the function name and remove
   kallsyms_lookup/ksym_buf.

3. Move "int ret" into the "if (work)" block, this looks more consistent.

Signed-off-by: Oleg Nesterov <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Acked-by: Tejun Heo <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Milos Vyletel <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Prarit Bhargava <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

0 files changed, 0 insertions, 0 deletions