Re: minor device number request for /dev/kvm (kernel-based virtual machine)

Avi Kivity
2007-03-01T13:05:06Z

Jan Engelhardt wrote:
> On Mar 1 2007 13:58, Avi Kivity wrote:
>
>> fs/char_dev.c:
>>
>>> int register_chrdev(unsigned int major, const char *name,
>>> const struct file_operations *fops)
>>> {
>>> struct char_device_struct *cd;
>>> struct cdev *cdev;
>>> char *s;
>>> int err = -ENOMEM;
>>>
>>> cd = __register_chrdev_region(major, 0, 256, name);
>>>
>> So misc minor numbers under 256 are not supported.
>>
>> What's the way out? Increase the region size? I don't know if that's safe.
>>
>
> If it does not increase memory usage, then possibly:
>
> __register_chrdev_region(major, 0, (~0U) & MINORMASK, name);
> or (1<<MINORMASK)-1 if that's more clear
>
>

I'm more worried about something in the chardev bowels not supporting
>8bit minors well.

--
error compiling committee.c: too many arguments to function