wait queue

1. Makefile

2. workQueue.c  (如果kernel module名字是workqueue, 会引起问题）

KVERSION = $(shell uname -r)
obj-m = workQueue.o


all:
        make -C /lib/modules/$(KVERSION)/build M=$(PWD) modules
clean:
        make -C /lib/modules/$(KVERSION)/build M=$(PWD) clean#ifndef __KERNEL__
#  define __KERNEL__
#endif
#ifndef MODULE
#  define MODULE
#endif

/*
 * Copyright (C) 2016,2017 Fernando Vanyo Garcia
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 *      Fernando Vanyo Garcia 
 *      Mi Shuang             
 */

#include 
#include 
#include 
#include 
#include 
#include 
#include 

#define AUTHOR "Mi Shuang"
#define DESC   "Simple example of kernel Work Queues"

MODULE_LICENSE("Dual BSD/GPL");
MODULE_AUTHOR(AUTHOR);
MODULE_DESCRIPTION(DESC);

struct work_ent {
        struct work_struct      real_work;
        struct delayed_work     timeout_work;
        int                     arg;
} work_ent;

static void thread_function(struct work_struct *work);

struct work_ent *test_wq;

static void thread_function(struct work_struct *work_arg)
{
        struct delayed_work *dwork = container_of(work_arg, struct delayed_work, work);
        struct work_ent *ent = container_of(dwork, struct work_ent, timeout_work);

        printk(KERN_INFO "%s: the data is: %d\n", __func__, ent->arg);
        schedule_delayed_work(&ent->timeout_work, HZ);

        return;
}

static int __init entry_point(void)
{
        test_wq = kmalloc(sizeof(*test_wq), GFP_KERNEL);
        INIT_DELAYED_WORK(&test_wq->timeout_work, thread_function);
        test_wq->arg = 1000;

        schedule_delayed_work(&test_wq->timeout_work, HZ);

        return 0;
}

static void __exit exit_point(void)
{
        //just in case:
        flush_delayed_work(&test_wq->timeout_work);
        cancel_delayed_work(&test_wq->timeout_work);

        kfree(test_wq);
        return;
}

module_init(entry_point);
module_exit(exit_point);