On Fri, Oct 9, 2020 at 3:06 PM Eric Biggers <ebigg...@kernel.org> wrote:
>
> It's a bit unintuitive that ppos=NULL means "use pos 0", not "use
> file->f_pos".
That's not at all what it means.
A NULL ppos means "this has no position at all", and is what we use
for FMODE_STREAM file descriptors (ie sockets, pipes, etc).
It also means that we don't do the locking for position updates.
The fact that "ki_pos" gets set to zero is just because it needs to be
_something_. It shouldn't actually ever be used for stream devices.
Linus
