scull驱动奇怪的问题。不能运行。已解决 - Chinaunix

obj-m := scull.o
scull-objs := scull_fops.o
KERNELDIR ?= /lib/modules/$(shell uname -r)/build
PWD := $(shell pwd)
default:
$(MAKE) -C $(KERNELDIR) M=$(PWD) modules
clean:
$(MAKE) -C $(KERNELDIR) M=$(PWD) clean
rm -fr *.o *.ko *.symvers *.mod.c

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#ifndef _SCULL_FOPS_H_
#define _SCULL_FOPS_H_
#include <linux/sched.h>
#include <linux/types.h>
//file file_operations etc.
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/cdev.h>
//copy
#include <asm/uaccess.h>
MODULE_LICENSE("Dual BSD/GPL");
loff_t scull_llseek(struct file *, loff_t, int);
ssize_t scull_read(struct file *, char __user *, size_t, loff_t *);
ssize_t scull_write(struct file *, const char __user *, size_t, loff_t *);
int scull_ioctl(struct inode *, struct file *, unsigned int, unsigned long);
int scull_open(struct inode *, struct file *);
int scull_release(struct inode *, struct file *);
struct scull_qset {
void **data;
struct scull_qset *next;
};
struct scull_dev {
struct scull_qset *data; /* Pointer to first quantum set */
int quantum; /* the current quantum size */
int qset; /* the current array size */
unsigned long size; /* amount of data stored here */
unsigned int access_key; /* used by sculluid and scullpriv */
struct semaphore sem; /* mutual exclusion semaphore */
struct cdev cdev; /* Char device structure */
};
int scull_trim(struct scull_dev *dev);
struct scull_qset *scull_follow(struct scull_dev *dev, int item);
#endif

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#include "scull_fops.h"
struct scull_dev dev;
//EXPORT_SYMBOL(dev);
struct file_operations scull_fops = {
.owner = THIS_MODULE,
.llseek = scull_llseek,
.read = scull_read,
.write = scull_write,
.ioctl = scull_ioctl,
.open = scull_open,
.release = scull_release
};
//EXPORT_SYMBOL(scull_fops);
loff_t
scull_llseek(struct file *filp, loff_t offp, int count) {
return 0;
}
ssize_t
scull_read(struct file *filp, char __user *buff, size_t count, loff_t *f_pos) {
printk("scull, scull_read() buff=%p, count=%i, *f_pos=%i\n", buff, count, *f_pos);
struct scull_dev *dev = (struct scull_dev*)filp->private_data;
struct scull_qset *p;
int quantum = dev->quantum;
int qset = dev->qset;
int itemsize = qset * quantum;
ssize_t retval = 0;
if (down_interruptible(&dev->sem))
return -ERESTARTSYS;
if (*f_pos >= dev->size)
goto out;
if (*f_pos + count > dev->size)
count = dev->size - *f_pos;
int item = (long)*f_pos / itemsize;
int rest = (long)*f_pos % itemsize;
int s_pos = rest / quantum;
int q_pos = rest % quantum;
//follow the list up to the right qset
p = scull_follow(dev, item);
//printk("p = %p \n", p);
//printk("p->data = %p \n", p->data);
//printk("p->data[s_pos] = %p \n", p->data[s_pos]);
if (p == NULL || p->data == NULL || p->data[s_pos] == NULL ) {
printk("something is wrong\n");
goto out;
}
char *str = p->data[s_pos] + q_pos;
//read only up to the end of this quantum
if (count > quantum - q_pos)
count = quantum - q_pos;
if (copy_to_user(buff, p->data[s_pos] + q_pos, count) != 0) {
retval = -EFAULT;
goto out;
}
printk("scull, success read %i bytes\n", count);
*f_pos += count;
retval = count;
out:
up(&dev->sem);
return retval;
}
ssize_t
scull_write(struct file *filp, const char __user *buff, size_t count, loff_t *f_pos) {
printk("scull, scull_write() start, buff=%p, count=%i, *f_pos=%i\n", buff, count, *f_pos);
struct scull_dev *dev = filp->private_data;
int itemsize = dev->qset * dev->quantum;
ssize_t retval = 0;
if (down_interruptible(&dev->sem)) {
return -ERESTARTSYS;
}
int item = (long)*f_pos / itemsize;
int rest = (long)*f_pos % itemsize;
int s_pos = rest / dev->quantum;
int q_pos = rest % dev->quantum;
struct scull_qset *p = scull_follow(dev, item);
if (p == NULL) {
printk("scull_follow() failed\n");
goto out;
}
if (p->data == NULL) {
p->data = kmalloc(sizeof(char*) * dev->qset, GFP_KERNEL);
if (p->data == NULL)
goto out;
memset(p->data, 0, sizeof(char*) * dev->qset);
}
if ((p->data)[s_pos] == NULL) {
(p->data)[s_pos] = kmalloc(dev->quantum, GFP_KERNEL);
if ((p->data)[s_pos] == NULL)
goto out;
}
if (count > dev->quantum - q_pos)
count = dev->quantum - q_pos;
//printk("p = %p \n", p);
//printk("p->data = %p \n", p->data);
//printk("p->data[s_pos] = %p \n", p->data[s_pos]);
if (copy_from_user(p->data[s_pos] + q_pos, buff, count) != 0) {
retval = -EFAULT;
goto out;
}
retval = count;
*f_pos += count;
if (dev->size < *f_pos) {
dev->size = *f_pos;
}
printk("scull, copy_from_user %i bytes\n", count);
out:
up(&dev->sem);
return retval;
}
int
scull_ioctl(struct inode *indoe, struct file *filp, unsigned int flag, unsigned long num) {
return 0;
}
int
scull_open(struct inode *inode, struct file *filp) {
printk("scull, scull_open() start\n");
struct scull_dev *dev;
dev = container_of(inode->i_cdev, struct scull_dev, cdev);
filp->private_data = dev;
if ((filp->f_flags & O_ACCMODE) == O_WRONLY) {
scull_trim(dev);
}
return 0;
}
int
scull_release(struct inode *inode, struct file *filp) {
printk("scull, scull_release() start\n");
return 0;
}
int
scull_trim(struct scull_dev *dev) {
printk("scull, scull_trim() start\n");
struct scull_qset *p = dev->data;
while (p != NULL) {
int i;
for (i=0; i<dev->qset; i++) {
kfree((p->data)[i]);
}
kfree(p->data);
struct scull_qset *next = p->next;
kfree(p);
p = next;
}
dev->size = 0;
dev->data = NULL;
return 0;
}
struct scull_qset *
scull_follow(struct scull_dev *dev, int item) {
printk("scull, scull_follow() start\n");
struct scull_qset *p = dev->data;
if (dev->data == NULL) {
dev->data = kmalloc(sizeof(struct scull_qset), GFP_KERNEL);
if (dev->data == NULL)
return NULL;
p = dev->data;
p->next = NULL;
p->data = NULL;
}
while (item-- != 0) {
if (p->next == NULL) {
p->next = kmalloc(sizeof(struct scull_qset), GFP_KERNEL);
if (p->next == NULL)
return NULL;
p->next->data = NULL;
p->next->next = NULL;
}
p = p->next;
}
return p;
}

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#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/cdev.h>
#include "scull_fops.h"
extern struct scull_dev dev;
extern struct file_operations scull_fops;
dev_t devno;
int major = 0;
int minor = 0;
int nr_devs = 4;
//init
int scull_init(void);
//exit
void scull_exit(void);
//分配设备
int alloc_dev(void);
//注册设备
int register_dev(void);
int
scull_init(void) {
printk("hello, scull\n");
printk("The process is \"%s\" (pid %i)\n", current->comm, current->pid);
if (alloc_dev() == -1) {
printk("scull: can't alloc devno, %i\n", major);
return -1;
}
if (register_dev() == -1) {
printk("scull, register_dev() failed\n");
return -1;
}
return 0;
}
void
scull_exit(void) {
printk("Goodbye, scull %i,%i\n", major, minor);
unregister_chrdev_region(devno, nr_devs);
cdev_del(&dev.cdev);
}
int
alloc_dev(void) {
int result = 0;
printk("scull, alloc_dev() start\n");
if (major == 0) {
result = alloc_chrdev_region(&devno, minor, nr_devs, "scull");
major = MAJOR(devno);
} else {
devno = MKDEV(major, minor);
result = register_chrdev_region(devno, nr_devs, "scull");
}
return result;
}
int
register_dev(void) {
printk("scull, register_dev() start\n");
dev.data = NULL;
dev.quantum = 4000;
dev.qset = 1000;
dev.size = 0;
init_MUTEX(&dev.sem);
cdev_init(&dev.cdev, &scull_fops);
dev.cdev.owner = THIS_MODULE;
dev.cdev.ops = &scull_fops;
return cdev_add(&dev.cdev, devno, 1);
}
module_init(scull_init);
module_exit(scull_exit);

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