stop_machine: reorganize stop_cpus() implementation

Refactor the queuing part of the stop cpus work from __stop_cpus() into
queue_stop_cpus_work().

The reorganization is to help future improvements to stop_machine()
and doesn't introduce any behavior difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20110623182056.897818337@sbsiddha-MOBL3.sc.intel.com
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 12 insertions, 4 deletions

diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
index 0cae1cc323d..4c89ee9fc56 100644
--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -136,10 +136,11 @@ DEFINE_MUTEX(stop_cpus_mutex);
 /* static data for stop_cpus */
 static DEFINE_PER_CPU(struct cpu_stop_work, stop_cpus_work);
 
-int __stop_cpus(const struct cpumask *cpumask, cpu_stop_fn_t fn, void *arg)
+static void queue_stop_cpus_work(const struct cpumask *cpumask,
+                                 cpu_stop_fn_t fn, void *arg,
+                                 struct cpu_stop_done *done)
 {
         struct cpu_stop_work *work;
-        struct cpu_stop_done done;
         unsigned int cpu;
 
         /* initialize works and done */
@@ -147,9 +148,8 @@ int __stop_cpus(const struct cpumask *cpumask, cpu_stop_fn_t fn, void *arg)
                 work = &per_cpu(stop_cpus_work, cpu);
                 work->fn = fn;
                 work->arg = arg;
-                work->done = &done;
+                work->done = done;
         }
-        cpu_stop_init_done(&done, cpumask_weight(cpumask));
 
         /*
          * Disable preemption while queueing to avoid getting
@@ -161,7 +161,15 @@ int __stop_cpus(const struct cpumask *cpumask, cpu_stop_fn_t fn, void *arg)
                 cpu_stop_queue_work(&per_cpu(cpu_stopper, cpu),
                                     &per_cpu(stop_cpus_work, cpu));
         preempt_enable();
+}
 
+static int __stop_cpus(const struct cpumask *cpumask,
+                       cpu_stop_fn_t fn, void *arg)
+{
+        struct cpu_stop_done done;
+
+        cpu_stop_init_done(&done, cpumask_weight(cpumask));
+        queue_stop_cpus_work(cpumask, fn, arg, &done);
         wait_for_completion(&done.completion);
         return done.executed ? done.ret : -ENOENT;
 }