Calling INIT_WORK() registers the specified work structure and function with the in-house default kernel-global workqueue. But it doesn't execute it – yet! You have to tell it when to execute your "work" by calling the schedule_work() API at the appropriate moment:
bool schedule_work(struct work_struct *work);
Clearly, the parameter to schedule_work() is the pointer to the work_struct structure (which you initialized earlier via the INIT_WORK() macro). It returns a Boolean (quoting directly from the source): %false if @work was already on the kernel-global workqueue and %true otherwise True. In effect, schedule_work() checks if the function that was specified (via the work structure) is already on the kernel-global workqueue; if not, it enqueues it there; if it already was there, it leaves it alone in the same position (it doesn't add one more instance). It then marks the...
