kthread: Add the helper macro kthread_run_on_cpu()

the helper macro kthread_run_on_cpu() inculdes
kthread_create_on_cpu/wake_up_process().
In some cases, use kthread_run_on_cpu() directly instead of
kthread_create_on_node/kthread_bind/wake_up_process() or
kthread_create_on_cpu/wake_up_process() or
kthreadd_create/kthread_bind/wake_up_process() to simplify the code.

Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>

include/linux/kthread.h

@@ -56,6 +56,27 @@ bool kthread_is_per_cpu(struct task_struct *k);
 	__k;								   \
 })
 
+/**
+ * kthread_run_on_cpu - create and wake a cpu bound thread.
+ * @threadfn: the function to run until signal_pending(current).
+ * @data: data ptr for @threadfn.
+ * @cpu: The cpu on which the thread should be bound,
+ * @namefmt: printf-style name for the thread. Format is restricted
+ *	     to "name.*%u". Code fills in cpu number.
+ *
+ * Description: Convenient wrapper for kthread_create_on_cpu()
+ * followed by wake_up_process().  Returns the kthread or
+ * ERR_PTR(-ENOMEM).
+ */
+#define kthread_run_on_cpu(threadfn, data, cpu, namefmt)	       \
+({								       \
+	struct task_struct *__k					       \
+		= kthread_create_on_cpu(threadfn, data, cpu, namefmt); \
+	if (!IS_ERR(__k))					       \
+		wake_up_process(__k);				       \
+	__k;							       \
+})
+
 void free_kthread_struct(struct task_struct *k);
 void kthread_bind(struct task_struct *k, unsigned int cpu);
 void kthread_bind_mask(struct task_struct *k, const struct cpumask *mask);