/*
Return the function table of a device.
Load the driver if needed.
Increment the reference count of module in question.
*/
static struct file_operations * get_chrfops(unsigned int major, unsigned int minor)
{
struct file_operations *ret = NULL;
if (!major || major >= MAX_CHRDEV)
return NULL;
read_lock(&chrdevs_lock);
ret = fops_get(chrdevs[major].fops);
read_unlock(&chrdevs_lock);
#ifdef CONFIG_KMOD
if (ret && isa_tty_dev(major)) {
lock_kernel();
if (need_serial(major,minor)) {
/* Force request_module anyway, but what for? */
fops_put(ret);
ret = NULL;
}
unlock_kernel();
}
if (!ret) {
char name[20];
sprintf(name, "char-major-%d", major);
request_module(name);
read_lock(&chrdevs_lock);
ret = fops_get(chrdevs[major].fops);
read_unlock(&chrdevs_lock);
}
#endif
return ret;
}
/*
Return the function table of a device.
Load the driver if needed.
*/
static struct file_operations * get_fops(
unsigned int major,
unsigned int minor,
unsigned int maxdev,
const char *mangle, /* String to use to build the module name */
struct device_struct tb[])
{
struct file_operations *ret = NULL;
if (major < maxdev){
#ifdef CONFIG_KMOD
/*
* I do get request for device 0. I have no idea why. It happen
* at shutdown time for one. Without the following test, the
* kernel will happily trigger a request_module() which will
* trigger kmod and modprobe for nothing (since there
* is no device with major number == 0. And furthermore
* it locks the reboot process :-(
*
* Jacques Gelinas ([email protected])
*
* A. Haritsis <*****@*****.**>: fix for serial module
* though we need the minor here to check if serial dev,
* we pass only the normal major char dev to kmod
* as there is no other loadable dev on these majors
*/
if ((isa_tty_dev(major) && need_serial(major,minor)) ||
(major != 0 && !tb[major].fops)) {
char name[20];
sprintf(name, mangle, major);
request_module(name);
}
#endif
ret = tb[major].fops;
}
return ret;
}
