1 files changed, 51 insertions, 1 deletions

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 714afad46539..d4dc69ddebd7 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -62,6 +62,7 @@ struct workqueue_struct {
         const char *name;
         int singlethread;
         int freezeable;         /* Freeze threads during suspend */
+        int rt;
 #ifdef CONFIG_LOCKDEP
         struct lockdep_map lockdep_map;
 #endif
@@ -766,6 +767,7 @@ init_cpu_workqueue(struct workqueue_struct *wq, int cpu)
 
 static int create_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu)
 {
+        struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
         struct workqueue_struct *wq = cwq->wq;
         const char *fmt = is_single_threaded(wq) ? "%s" : "%s/%d";
         struct task_struct *p;
@@ -781,7 +783,8 @@ static int create_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu)
          */
         if (IS_ERR(p))
                 return PTR_ERR(p);
-
+        if (cwq->wq->rt)
+                sched_setscheduler_nocheck(p, SCHED_FIFO, &param);
         cwq->thread = p;
 
         return 0;
@@ -801,6 +804,7 @@ static void start_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu)
 struct workqueue_struct *__create_workqueue_key(const char *name,
                                                 int singlethread,
                                                 int freezeable,
+                                                int rt,
                                                 struct lock_class_key *key,
                                                 const char *lock_name)
 {
@@ -822,6 +826,7 @@ struct workqueue_struct *__create_workqueue_key(const char *name,
         lockdep_init_map(&wq->lockdep_map, lock_name, key, 0);
         wq->singlethread = singlethread;
         wq->freezeable = freezeable;
+        wq->rt = rt;
         INIT_LIST_HEAD(&wq->list);
 
         if (singlethread) {
@@ -965,6 +970,51 @@ undo:
         return ret;
 }
 
+#ifdef CONFIG_SMP
+struct work_for_cpu {
+        struct work_struct work;
+        long (*fn)(void *);
+        void *arg;
+        long ret;
+};
+
+static void do_work_for_cpu(struct work_struct *w)
+{
+        struct work_for_cpu *wfc = container_of(w, struct work_for_cpu, work);
+
+        wfc->ret = wfc->fn(wfc->arg);
+}
+
+/**
+ * work_on_cpu - run a function in user context on a particular cpu
+ * @cpu: the cpu to run on
+ * @fn: the function to run
+ * @arg: the function arg
+ *
+ * This will return -EINVAL in the cpu is not online, or the return value
+ * of @fn otherwise.
+ */
+long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg)
+{
+        struct work_for_cpu wfc;
+
+        INIT_WORK(&wfc.work, do_work_for_cpu);
+        wfc.fn = fn;
+        wfc.arg = arg;
+        get_online_cpus();
+        if (unlikely(!cpu_online(cpu)))
+                wfc.ret = -EINVAL;
+        else {
+                schedule_work_on(cpu, &wfc.work);
+                flush_work(&wfc.work);
+        }
+        put_online_cpus();
+
+        return wfc.ret;
+}
+EXPORT_SYMBOL_GPL(work_on_cpu);
+#endif /* CONFIG_SMP */
+
 void __init init_workqueues(void)
 {
         cpu_populated_map = cpu_online_map;