workqueue: introduce wq_per_cpu() helper

Cleanup.  A number of per_cpu_ptr(wq->cpu_wq, cpu) users have to check that
cpu is valid for this wq.  Make a simple helper.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 0eb9b33f1d917a95da8df146b0657d8db3f53d39..985902e2e071e3775c26384528b778daf8d4d861 100644 (file)
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -86,6 +86,14 @@ static const cpumask_t *wq_cpu_map(struct workqueue_struct *wq)
                ? &cpu_singlethread_map : &cpu_populated_map;
 }
 
+static
+struct cpu_workqueue_struct *wq_per_cpu(struct workqueue_struct *wq, int cpu)
+{
+       if (unlikely(is_single_threaded(wq)))
+               cpu = singlethread_cpu;
+       return per_cpu_ptr(wq->cpu_wq, cpu);
+}
+
 /*
  * Set the workqueue on which a work item is to be run
  * - Must *only* be called if the pending flag is set
@@ -142,16 +150,14 @@ static void __queue_work(struct cpu_workqueue_struct *cwq,
  */
 int fastcall queue_work(struct workqueue_struct *wq, struct work_struct *work)
 {
-       int ret = 0, cpu = get_cpu();
+       int ret = 0;
 
        if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) {
-               if (unlikely(is_single_threaded(wq)))
-                       cpu = singlethread_cpu;
                BUG_ON(!list_empty(&work->entry));
-               __queue_work(per_cpu_ptr(wq->cpu_wq, cpu), work);
+               __queue_work(wq_per_cpu(wq, get_cpu()), work);
+               put_cpu();
                ret = 1;
        }
-       put_cpu();
        return ret;
 }
 EXPORT_SYMBOL_GPL(queue_work);
@@ -161,12 +167,8 @@ void delayed_work_timer_fn(unsigned long __data)
        struct delayed_work *dwork = (struct delayed_work *)__data;
        struct cpu_workqueue_struct *cwq = get_wq_data(&dwork->work);
        struct workqueue_struct *wq = cwq->wq;
-       int cpu = smp_processor_id();
-
-       if (unlikely(is_single_threaded(wq)))
-               cpu = singlethread_cpu;
 
-       __queue_work(per_cpu_ptr(wq->cpu_wq, cpu), &dwork->work);
+       __queue_work(wq_per_cpu(wq, smp_processor_id()), &dwork->work);
 }
 
 /**
@@ -209,9 +211,7 @@ int queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
                BUG_ON(!list_empty(&work->entry));
 
                /* This stores cwq for the moment, for the timer_fn */
-               set_wq_data(work,
-                       per_cpu_ptr(wq->cpu_wq, wq->singlethread ?
-                               singlethread_cpu : raw_smp_processor_id()));
+               set_wq_data(work, wq_per_cpu(wq, raw_smp_processor_id()));
                timer->expires = jiffies + delay;
                timer->data = (unsigned long)dwork;
                timer->function = delayed_work_timer_fn;