Linux kernel kthread用法

/**
 * kthread_create - create a kthread on the current node
 * @threadfn: the function to run in the thread
 * @data: data pointer for @threadfn()
 * @namefmt: printf-style format string for the thread name
 * @arg...: arguments for @namefmt.
 *
 * This macro will create a kthread on the current node, leaving it in
 * the stopped state.  This is just a helper for kthread_create_on_node();
 * see the documentation there for more details.
 */
#define kthread_create(threadfn, data, namefmt, arg...) \
	kthread_create_on_node(threadfn, data, NUMA_NO_NODE, namefmt, ##arg)

/**
 * kthread_run - create and wake a thread.
 * @threadfn: the function to run until signal_pending(current).
 * @data: data ptr for @threadfn.
 * @namefmt: printf-style name for the thread.
 *
 * Description: Convenient wrapper for kthread_create() followed by
 * wake_up_process().  Returns the kthread or ERR_PTR(-ENOMEM).
 */
#define kthread_run(threadfn, data, namefmt, ...)			   \
({									   \
	struct task_struct *__k						   \
		= kthread_create(threadfn, data, namefmt, ## __VA_ARGS__); \
	if (!IS_ERR(__k))						   \
		wake_up_process(__k);					   \
	__k;								   \
})

struct task_struct *t1 = kthread_create(threadfn, data, "name%d", i);
if (!IS_ERR(t1))
	wake_up_process(t1);

struct task_struct *t2 = kthread_run(threadfn, data, "name%d", i);

// test1.c
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/kthread.h>
#include <linux/sched.h>
#include <linux/semaphore.h>
#include <linux/spinlock.h>

MODULE_LICENSE("GPL");

struct para {
	const char *msg;
	struct completion entered;
};
static int func(void *__para)
{
	struct para *para = (struct para *)__para;
	complete(&para->entered);
	// Do something here

	/* Wait for kthread_stop */
	set_current_state(TASK_INTERRUPTIBLE);
	while (!kthread_should_stop()) {
		schedule();
		set_current_state(TASK_INTERRUPTIBLE);
	}
	set_current_state(TASK_RUNNING);
	printk("%s %s return\n", __func__, para->msg);
	return 0;
}
static int __init start_init(void)
{
	struct task_struct *t1;
	struct para para;
	int ret;

	printk(KERN_INFO "Thread Creating...\n");
	para.msg = "t1";
	init_completion(&para.entered);
	t1 = kthread_run(func, &para, "t1");
	if (IS_ERR(t1)) {
		WARN_ON(1);
		return 0;
	}
	wait_for_completion(&para.entered);
	ret = kthread_stop(t1);
	printk("t1 stopped, exit code %d\n", ret);

	return 0;
}

static void __exit end_exit(void)
{
}

module_init(start_init)
module_exit(end_exit)

obj-m += test1.o
all:
        $(MAKE) -C /lib/modules/$(shell uname -r)/build M=`pwd`
clean:
        $(MAKE) -C /lib/modules/$(shell uname -r)/build M=`pwd` clean