I am trying to build a simple kernel module. Following are the contents of file involved in it:

module.c:

    #include <linux/init.h>

    #include <linux/fs.h>

    #include <linux/device.h>

    #include <linux/kernel.h>

    #include "header.h"













    static int device_open(struct inode *inode, struct file *file)

    {

    printk("

 Open 

");

    return 0;

    }



    static int device_ioctl(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long args)

    {

    switch(cmd)

    {

    case IOCTL_CMD:

    printk(KERN_ALERT "

 %s 

", (char *)args);

    break;

    }

    return 0;

    }





    static int device_release(struct inode *inode, struct file *file)

    {

    printk("

 Release 

");

    return 0;

    }



    static struct class *my_class;



    static struct file_operations fops={

    .open = device_open,

    .release = device_release,

    .compat_ioctl = device_ioctl

    };



    static int hello_init(void)

    {

    major_no = register_chrdev(0, DEVICE_NAME, &fops);

    printk("

 Major_no : %d", major_no);



    my_class = class_create(THIS_MODULE, DEVICE_NAME);

    device_create(my_class, NULL, MKDEV(major_no,0), NULL, DEVICE_NAME);

    printk("

 Device Initialized in kernel ....!!!");

    return 0;

    }









    static void hello_exit(void)

    {

    printk("

 Device is Released or closed 

");

    device_destroy(my_class,MKDEV(major_no,0));

    class_unregister(my_class);

    class_destroy(my_class);

    unregister_chrdev(major_no, DEVICE_NAME);

    printk("

===============================================================

");

    }







    module_init(hello_init);

    module_exit(hello_exit);



    MODULE_LICENSE("GPL");

appln.c

    #include <stdio.h>

    #include <fcntl.h>

    #include <string.h>



    #include "header.h"



    int main()

    {

    int fd;

    char * msg = "yahoooo";

    fd = open(DEVICE_PATH, O_RDWR);

    ioctl(fd, IOCTL_CMD, msg);

    printf("ioctl executed

");

    close(fd);

    return 0;

    }

header.h:

    #include <linux/ioctl.h>

    #include <linux/kdev_t.h> /* for MKDEV */



    #define DEVICE_NAME "my_dev"

    #define DEVICE_PATH "/dev/my_dev"

    #define WRITE 0

    static int major_no;

    #define MAGIC_NO '4'

    /* 

     * Set the message of the device driver 

     */

    #define IOCTL_CMD _IOR(MAGIC_NO, 0, char *)

My module loads perfectly(I can see the mesg in hello_init() function). But when i run the appln.c program, even when it makes the ioctl() call, I see no result of it. Can someone tell why is the module ignoring my ioctl call.

Thanks,