Re: [PATCH] wait: include linux/sched.h

[Peter Zijlstra <a.p.zijlstra@chello.nl>]

On Fri, 2011-05-06 at 09:54 +0200, Ingo Molnar wrote:

> > diff --git a/include/linux/wait.h b/include/linux/wait.h
> > index 3efc9f3..667a3d7 100644
> > --- a/include/linux/wait.h
> > +++ b/include/linux/wait.h
> > @@ -22,6 +22,7 @@
> >  #include <linux/list.h>
> >  #include <linux/stddef.h>
> >  #include <linux/spinlock.h>
> > +#include <linux/sched.h>
> >  #include <asm/system.h>
> >  #include <asm/current.h>
> 
> I'm quite sure this will break the build all around the place, because sched.h 
> itself uses wait.h primitives.

I'm very sure it will, people keep proposing this.

> To fix these super-headers like sched.h and to make wait.h self-sufficient the 
> right and cleanest approach would be to split data types and primitive accessor 
> functions from higher level helper methods (which inevitably mix different 
> domains) and put them into two separate files.
> 
> We have a few such split files in the kernel tree, spinlock_types.h and 
> spinlock_api.h, and this concept works reasonably well.
> 
> So here we'd need wait_types.h and wait_api.h and of course sched_types.h and 
> sched_api.h.
> 
> For simplicity of migration wait_api.h could be wait.h itself and sched_api.h 
> could be sched.h itself.

Argh, please don't. I've been arguing against that for a while now.

The right thing to do is to clean up sched.h and remove a lot of the
non-scheduler bits in there, like all the process and signal bits.