Executing a user-space function from the kernel space

Question

Im writing a custom device driver in linux that has to be able to respond very rapidly on interrupts. Code to handle this already exists in a user-space implementation but t

Answer 1

I am also facing the same problem, I read this document http://people.ee.ethz.ch/~arkeller/linux/multi/kernel_user_space_howto-6.html, so planning to use signals. In my case there is no chance of losing signals, because
1. the system is closed loop, after signals executed then only I will get another signal.
2. And I am using POSIX real-time signals.