call_usermodehelper_exec — start a usermode application
information about the subprocessa
wait for the application to finish and return status. when -1 don't wait at all, but you get no useful error back when the program couldn't be exec'ed. This makes it safe to call from interrupt context.
Runs a user-space application. The application is started asynchronously if wait is not set, and runs as a child of keventd. (ie. it runs with full root capabilities).