虚拟字符设备globalmem遇到的问题，忘大侠解答下？
我想自动创建设备文件，于是就写了下面的程序，但是能够MAKE成功，但是一旦insmod 进内核，linux就l死机，我是在PC上虚拟的LINUX系统，哪位大侠帮忙看下程序#include <linux/module.h>
#include <linux/types.h>
#include <linux/fs.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/cdev.h>
#include <asm/io.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <linux/poll.h>
#include <linux/device.h> /* device_create()*/
#define GLOBALFIFO_SIZE 0x1000 /*全局fifo最大4K字节*/
#define FIFO_CLEAR 0x1/*清0全局内存的长度*/
#define GLOBALFIFO_MAJOR 200 /*预设的globalfifo的主设备号*/
static int globalfifo_major = GLOBALFIFO_MAJOR;
/*globalfifo设备结构体*/
struct globalfifo_dev
{
struct cdev cdev; /*cdev结构体*/
unsigned int current_len; /*fifo有效数据长度*/
unsigned char mem; /*全局内存*/
struct semaphore sem; /*并发控制用的信号量*/
wait_queue_head_t r_wait; /*阻塞读用的等待队列头*/
wait_queue_head_t w_wait; /*阻塞写用的等待队列头*/
};
struct globalfifo_dev *globalfifo_devp; /*设备结构体指针*/
/*文件打开函数*/
int globalfifo_open(struct inode *inode, struct file *filp)
{
/*将设备结构体指针赋值给文件私有数据指针*/
filp->private_data = globalfifo_devp;
return 0;
}
/*文件释放函数*/
int globalfifo_release(struct inode *inode, struct file *filp)
{
return 0;
}
/* ioctl设备控制函数 */
static int globalfifo_ioctl(struct inode *inodep, struct file *filp, unsigned
int cmd, unsigned long arg)
{
struct globalfifo_dev *dev = filp->private_data;/*获得设备结构体指针*/
switch (cmd)
{
case FIFO_CLEAR:
down(&dev->sem); //获得信号量
dev->current_len = 0;
memset(dev->mem,0,GLOBALFIFO_SIZE);
up(&dev->sem); //释放信号量
printk(KERN_INFO "globalfifo is set to zero\n");
break;
default:
return- EINVAL;
}
return 0;
}
static unsigned int globalfifo_poll(struct file *filp, poll_table *wait)
{
unsigned int mask = 0;
struct globalfifo_dev *dev = filp->private_data; /*获得设备结构体指针*/
down(&dev->sem);
poll_wait(filp, &dev->r_wait, wait);
poll_wait(filp, &dev->w_wait, wait);
/*fifo非空*/
if (dev->current_len != 0)
{
mask |= POLLIN | POLLRDNORM; /*标示数据可获得*/
}
/*fifo非满*/
if (dev->current_len != GLOBALFIFO_SIZE)
{
mask |= POLLOUT | POLLWRNORM; /*标示数据可写入*/
}
up(&dev->sem);
return mask;
}
/*globalfifo读函数*/
static ssize_t globalfifo_read(struct file *filp, char __user *buf, size_t count,
loff_t *ppos)
{
int ret;
struct globalfifo_dev *dev = filp->private_data; //获得设备结构体指针
DECLARE_WAITQUEUE(wait, current); //定义等待队列
down(&dev->sem); //获得信号量
add_wait_queue(&dev->r_wait, &wait); //进入读等待队列头
/* 等待FIFO非空 */
if (dev->current_len == 0)
{
if (filp->f_flags &O_NONBLOCK)//非阻塞
{
ret =- EAGAIN;
goto out;
}
//阻塞
__set_current_state(TASK_INTERRUPTIBLE); //改变进程状态为睡眠
up(&dev->sem);
schedule(); //调度其他进程执行
if (signal_pending(current))
//如果是因为信号唤醒
{
ret =- ERESTARTSYS;
goto out2;
}
down(&dev->sem);
}
/* 拷贝到用户空间 */
if (count > dev->current_len)
count = dev->current_len;
if (copy_to_user(buf, dev->mem, count)) //从内核空间拷贝到用户空间
{
ret =- EFAULT;
goto out;
}
else
{
memcpy(dev->mem, dev->mem + count, dev->current_len - count);//fifo(管道)数据前移
dev->current_len -= count; //有效数据长度减少
printk(KERN_INFO "read %d bytes(s),current_len:%d\n", count, dev->current_len);
wake_up_interruptible(&dev->w_wait); //唤醒写等待队列
ret = count;
}
out: up(&dev->sem); //释放信号量
out2:remove_wait_queue(&dev->w_wait, &wait); //从附属的等待队列头移除
set_current_state(TASK_RUNNING);
return ret;
}
/*globalfifo写操作*/
static ssize_t globalfifo_write(struct file *filp, const char __user *buf,
size_t count, loff_t *ppos)
{
struct globalfifo_dev *dev = filp->private_data; //获得设备结构体指针
int ret;
DECLARE_WAITQUEUE(wait, current); //定义等待队列
down(&dev->sem); //获取信号量
add_wait_queue(&dev->w_wait, &wait); //进入写等待队列头
/* 等待FIFO非满 */
if (dev->current_len == GLOBALFIFO_SIZE)
{
if (filp->f_flags &O_NONBLOCK)
//如果是非阻塞访问
{
ret =- EAGAIN;
goto out;
}
__set_current_state(TASK_INTERRUPTIBLE); //改变进程状态为睡眠
up(&dev->sem);
schedule(); //调度其他进程执行
if (signal_pending(current))
//如果是因为信号唤醒
{
ret =- ERESTARTSYS;
goto out2;
}
down(&dev->sem); //获得信号量
}
/*从用户空间拷贝到内核空间*/
if (count > GLOBALFIFO_SIZE - dev->current_len)
count = GLOBALFIFO_SIZE - dev->current_len;
if (copy_from_user(dev->mem + dev->current_len, buf, count))
{
ret =- EFAULT;
goto out;
}
else
{
dev->current_len += count;
printk(KERN_INFO "written %d bytes(s),current_len:%d\n", count, dev
->current_len);
wake_up_interruptible(&dev->r_wait); //唤醒读等待队列
ret = count;
}
out: up(&dev->sem); //释放信号量
out2:remove_wait_queue(&dev->w_wait, &wait); //从附属的等待队列头移除
set_current_state(TASK_RUNNING);
return ret;
}
/*文件操作结构体*/
static const struct file_operations globalfifo_fops =
{
.owner = THIS_MODULE,
.read = globalfifo_read,
.write = globalfifo_write,
.ioctl = globalfifo_ioctl,
.poll = globalfifo_poll,
.open = globalfifo_open,
.release = globalfifo_release,
};
/*初始化并注册cdev*/
static void globalfifo_setup_cdev(struct globalfifo_dev *dev, int index)
{
int err, devno = MKDEV(globalfifo_major, index);
cdev_init(&dev->cdev, &globalfifo_fops);
dev->cdev.owner = THIS_MODULE;
dev->cdev.ops = &globalfifo_fops;
err = cdev_add(&dev->cdev, devno, 1);
if (err)
printk(KERN_NOTICE "Error %d adding LED%d", err, index);
}
/*设备驱动模块加载函数*/
int globalfifo_init(void)
{
struct class *myclass;int ret;
dev_t devno = MKDEV(globalfifo_major, 0);
/* 申请设备号*/
if (globalfifo_major)
ret = register_chrdev_region(devno, 1, "globalfifo");
else/* 动态申请设备号 */
{
ret = alloc_chrdev_region(&devno, 0, 1, "globalfifo");
globalfifo_major = MAJOR(devno);
}
if (ret < 0)
return ret;
/* 动态申请设备结构体的内存*/
globalfifo_devp = kmalloc(sizeof(struct globalfifo_dev), GFP_KERNEL);
if (!globalfifo_devp) /*申请失败*/
{
ret =- ENOMEM;
goto fail_malloc;
}
memset(globalfifo_devp, 0, sizeof(struct globalfifo_dev));
globalfifo_setup_cdev(globalfifo_devp, 0);
myclass = class_create(THIS_MODULE,"test_char"); /*在sys下创建类目录/sys/class/test_char*/
device_create(myclass, NULL, MKDEV(globalfifo_major,0), NULL, "globalmem_creat");
init_MUTEX(&globalfifo_devp->sem); /*初始化信号量*/
init_waitqueue_head(&globalfifo_devp->r_wait); /*初始化读等待队列头*/
init_waitqueue_head(&globalfifo_devp->w_wait); /*初始化写等待队列头*/
/*自动创建设备文件*/
return 0;
fail_malloc: unregister_chrdev_region(devno, 1);
return ret;
}
/*模块卸载函数*/
void globalfifo_exit(void)
{
cdev_del(&globalfifo_devp->cdev); /*注销cdev*/
kfree(globalfifo_devp); /*释放设备结构体内存*/
unregister_chrdev_region(MKDEV(globalfifo_major, 0), 1); /*释放设备号*/
}
MODULE_AUTHOR("Song Baohua");
MODULE_LICENSE("Dual BSD/GPL");
module_param(globalfifo_major, int, S_IRUGO);
module_init(globalfifo_init);
module_exit(globalfifo_exit);
insmod就出问题的话
globalfifo_init(void)这个函数出的问题的可能性比较大了
好像函数中用到了好多同步机制，或许某个地方出了混乱使你的驱动死锁了，或者什么情况，我水平只能到这了
回复 2# xfortune
谢谢啊 查查系统日志吧，看有什么提示
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