module -- comiple warning.... copy_from_user() , copy_to_user(), verify

HI,
I want to compile test.c -- it is very simple module programming...
I don't know why copy_from_user() , copy_to_user(), verify_area is
warning...

what's wrong....

=== test.c===
#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>

#include <linux/fs.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/fcntl.h>

#include <asm/uaccess.h>
#include <asm/io.h>

#include "ioctl_test.h"

#define DEV_NAME "testdev"
#define DEV_MAJOR 240

ssize_t ioctltest_read (struct file *fp, char *buf, size_t count , loff_t
*f_ops)
{
verify_area (VERIFY_WREITE, (void *)buf , count );

return some_count;
}
int ioctltest_open (struct inode *inode, struct file *filp)
{
return 0;
}

int ioctltest_release (struct inode *inode, struct file *filp)
{
return 0;
}

int ioctltest_ioctl (struct inode *inode, struct file *filp, unsigned int
cmd, unsigned long arg)
{

char kbuf[128] = {0,};

switch( cmd )
{

case WRITE :
...
..
copy_from_user ( (void *)&kbuf, (const void *) arg, size );

case READ :
..
..
strcpy ( kbuf , "test" );
copy_to_user ( (void *) arg, (const void *)
&kbuf, 4 );
break;

}

return 0;
}

struct file_operations ioctltest_fops =
{
.owner = THIS_MODULE,
.ioctl = ioctltest_ioctl,
.open = ioctltest_open,
.release = ioctltest_release,
};

int ioctltest_init(void)
{
int result;

result = register_chrdev( DEV_MAJOR, DEV_NAME, &ioctltest_fops);
if (result < 0) return result;

return 0;
}

void ioctltest_exit(void)
{
unregister_chrdev( DEV_MAJOR, DEV_NAME );
}

module_init(ioctltest_init);
module_exit(ioctltest_exit);

MODULE_LICENSE("Dual BSD/GPL");

==== Makefile =========
obj-m := test.o

KDIR := /lib/modules/$(shell uname -r)/build
PWD := $(shell pwd)

default:
$(MAKE) -C $(KDIR) SUBDIRS=$(PWD) modules
clean:
rm -rf *.ko
rm -rf *.mod.*
rm -rf .*.cmd
rm -rf *.o

==== when I compile ...

/root/work/test/src/m_src/test.c:618: warning: ignoring return value of
`copy_from_user', declared with attribute warn_unused_result
/root/work/test/src/m_src/test.c: In function `test_ioctl':
/root/work/test/src/m_src/test.c:666: warning: ignoring return value of
`copy_from_user', declared with attribute warn_unused_result
/root/work/test/src/m_src/test.c:677: warning: ignoring return value of
`copy_from_user', declared with attribute warn_unused_result
/root/work/test/src/m_src/test.c:687: warning: ignoring return value of
`copy_from_user', declared with attribute warn_unused_result
/root/work/test/src/m_src/test.c:695: warning: ignoring return value of
`copy_from_user', declared with attribute warn_unused_result
/root/work/test/src/m_src/test.c:717: warning: ignoring return value of
`copy_to_user', declared with attribute warn_unused_result
/root/work/test/src/m_src/test.c:728: warning: ignoring return value of
`copy_to_user', declared with attribute warn_unused_result
/root/work/test/src/m_src/test.c:732: warning: ignoring return value of
`copy_from_user', declared with attribute warn_unused_result
/root/work/test/src/m_src/test.c:740: warning: ignoring return value of
`copy_from_user', declared with attribute warn_unused_result
/root/work/test/src/m_src/test.c:745: warning: ignoring return value of
`copy_to_user', declared with attribute warn_unused_result
Building modules, stage 2.
MODPOST 1 modules
WARNING: "verify_area" [/root/work/test/src/m_src/test.ko] undefined!
CC /root/work/test/src/m_src/test.mod.o
LD [M] /root/work/test/src/m_src/test.ko
make[1]: Leaving directory `/usr/src/linux-2.6.20'

Thanks...

module -- comiple warning.... copy_from_user() , copy_to_user(), verify_area ..