call a kernel module function from program at user space
I developed a kernel module and some functions on it. Now i need to develop a program in the user space and call some functions which are in the kernel module.
I also need to access some global variable that are in the kernel module on my program at the user space.
Answer
There is complete overview of linux-kernel module and user-space program interacting http://wiki.tldp.org/kernel_user_space_howto "Kernel Space, User Space Interfaces" by Ariane Keller (it is from 2008-09-28, but about 2.6 kernels; only major new way is relayfs)
No ordinary function call from user space to kernel space is listed, only syscall (adding new syscall is not easy) and upcall (call in inverse direction).
One of easiest interface is ioctl; but you can't start to use ioctl before creating procfs, sysfs or similiar file.
Other is sysctl; but sysctl is more eligible to reading/writing to global variable. (It is hard to pass several parameters via sysctl interface).