Re: system call problem

From: Kasper Dupont (
Date: 09/21/05

Date: Wed, 21 Sep 2005 16:56:00 +0200

Peter wrote:
> what's the relationship between system calls and functions in
> device driver?

system calls may indirectly call functions in device

> Is system call defined just as interface between
> user and device??


> When we invoke the certain system call for the
> specifical _FILE_ ? that's, we, actually, invoke an implementation by
> the corresponding device driver?

Some system calls do call methods in the file object
coresponding to the path or file descriptor given as
argument. We have VFS to glue this stuff together,
that is where most of the tricky stuff is going on.

> But obviously the functions in
> file_operations in device driver just a subset of the system calls!??

Of course. There are lots of system calls that doesn't
even deal with files.

> Is my thought right?

I don't know what you are thinking.

> if not, what's wrong here?

Is there anything wrong?

Kasper Dupont
Note to self: Don't try to allocate
256000 pages with GFP_KERNEL on x86.