I am constantly finding the "handler" keyword in the linux source. I thought it had only to do with interrupts (interrupt handlers,etc), however i see it in other forms,too; for example "Call the commit handler in the driver". Is "handler" a more general naming convention? To what does it usually refer to? So far i have understood, that it generally refers to functions, which finish certain jobs. If you can point me to any links ...
Thanks

I have never seen "handler" refer to anything except a function that's called to, well, handle something. Usually an event or signal that's called asynchronously.

In c++ terminology (can also be in c) , a handler (also called an exception handler) is a piece of code that manages program events : it catches the event and reacts to it.
Similarly (as being said) you can also have signal handlers. You tell your program that whenever a signal appears, it has to be treated by sig_handler. Then all the error/signal/events/.. are handled in the same function.
The same applies for an interrupt, as yous said. When an interrupt is raised, the handler deals with it, does the action and returns.

A handler can also be an overclass. Rather than using directly a door, you will use the handle to open the door. In that way a handler can also be a helper and this helper can be reused for other objects ( a trunk, a window,..) , it centralizes the entry for an action.