I'm writing new kernel module and I add implement new IOCTL's.
Is there any rule that I should follow with IOCTL's numbering ?
Maybe there is some "user range" ?
I work with kernel 2.6.21 on embedded platform.
IOCTLs are defined to be device dependent -- if there were "standard" ioctls for people to implement, these would be syscalls like read
and write
.
There are a few conventions for ioctl numbers: