Re: [RFC][5/11][MANUX] Kernel compatibility : major/minor numbers

Austin S Hemmelgarn
2014-04-15T15:02:58Z

On 2014-04-15 09:42, Emmanuel Colbus wrote:
> Now, back to the filesystem...
>
> In order to associate devices to their files, the Linux kernel uses
> their major and minor numbers. However, mine doesn't; instead, I've
> attributed myself a single group of values (major=0, minor=0, for both
> character-mode and block-mode special files), with the meaning (for the
> userspace) "you cannot identify the content of this file based on its
> major and minor numbers".
>
> As for my kernel, there is a syscall to associate such files with their
> proper peripherals (asper(2)), after which it internally identifies them
> using their inode and partition numbers; as for userspace, it has no
> choice but to use their names, as usual.
>
> Do you have any objection to my taking of these values?
>

According to Documentation/devices.txt:
0 Unnamed devices (e.g. non-device mounts)
0 = reserved as null device number

Based on this, I would say that you are probably better off using one of
the local use numbers (60-63 and 250-254 are reserved for local and
experimental use)