size_t len;
char buffer[0];
};
+struct hello_buffer *hello;
static int hello_open(struct inode *ino, struct file *fp)
{
- struct hello_buffer *hello = kzalloc(sizeof(*hello) + MAXLEN, GFP_KERNEL);
- if (!hello)
- return -ENOMEM;
- memcpy(hello->buffer, default_greeting, sizeof(default_greeting));
- hello->len = sizeof(default_greeting);
- fp->private_data = hello;
return 0;
}
static ssize_t hello_read(struct file *fp, char __user *buf, size_t sz,
loff_t *pos)
{
- struct hello_buffer *hello = fp->private_data;
int r;
if (sz + *pos > hello->len)
sz = hello->len - *pos;
static ssize_t hello_write(struct file *fp, const char __user *buf, size_t sz,
loff_t *pos)
{
- struct hello_buffer *hello = fp->private_data;
int r;
if (sz + *pos > MAXLEN)
sz = MAXLEN - *pos;
static int hello_release(struct inode *ino, struct file *fp)
{
- kfree(fp->private_data);
return 0;
}
static int __init ch_init(void)
{
int r = 0;
+ hello = kzalloc(sizeof(*hello) + MAXLEN, GFP_KERNEL);
+ if (!hello) {
+ r = -ENOMEM;
+ goto out;
+ }
+ memcpy(hello->buffer, default_greeting, sizeof(default_greeting));
+ hello->len = sizeof(default_greeting);
r = alloc_chrdev_region(&devnum, 0, 256, "hello");
if (r)
- goto out;
+ goto reg_out;
dev = cdev_alloc();
if (!dev) {
r = -ENOMEM;
kfree(dev);
cdev_out:
unregister_chrdev_region(devnum, 256);
+reg_out:
+ kfree(hello);
out:
return r;
}
{
cdev_del(dev);
unregister_chrdev_region(devnum, 256);
+ kfree(hello);
}
module_init(ch_init);