Re: [PATCH] Add module_kernel_thread for threads that live in modules.

[Martin Diehl]

On Mon, 16 Jun 2003, Rusty Russell wrote:

> In message <[e-mail]> you write:
> > Why using keventd? Personally I'd prefer a synchronous thread start/stop, 
> > particularly with the thread living in a module.
> > Maybe some generalisation of:
> 
> It would be syncronous:

You mean your cleanup_thread would block for completion of the keventd 
stuff? Ok, this would work. But then, when calling cleanup_thread, f.e. we 
must not hold any semaphore which might be acquired by _any_ other work 
scheduled for keventd or we might end in deadlock (like the rtnl+hotplug 
issue we had seen recently).

> but doing kernel_thread yourself means trying
> to clean up using daemonize et al, which is incomplete and always
> makes me nervous.

I thought this was fixed in 2.5 for some time now, but seems I shouldn't 
rely on that ;-)

> An implementation detail to users, but IMHO an important one.
> 
> Also, this replaces complete_and_exit: the thread can just exit.  This
> simplifies things for the users, too...

Personally I do like the complete_and_exit thing as a simple and clear 
finalisation point. And if I didn't miss something above wrt. your 
cleanup_kthread being synchronous I'm not sure whether the locking 
implication do really make things easier - YMMV of course.

Thanks.
Martin