finishing the if.h/if_var.h split

[Bruce Evans]

On Tue, 30 Sep 2003, John Baldwin wrote:

> On 30-Sep-2003 Bruce Evans wrote:
> > On Mon, 29 Sep 2003, Brooks Davis wrote:
> >> Unfortunately, "soon" hasn't happened yet and it is now tripping me
> >> up.  To add the if_dev member to struct ifnet (see the forthcoming
> >> post on that subject), it is necessary for sys/bus.h to be included in
> >> net/if_var.h
> >
> > That would be namespace pollution, so it is not permitted :-).  Requiring
> > all files that include <sys/if_var.h> (and especially <sys/if.h> to
> > include <sys/bus.h> would be interface breakage so it is even less
> > permitted.
>
> Well, if if.h stops including if_var.h, then only kernel files that
> include net/if_var.h would need sys/bus.h.  I think that's manageable.

All userland files that include net/if_var.h would also need it (except
they would only need device_t).

> >> which in turn requires that if_var.h NOT be included in
> >> genassym.c.
> >
> > Do you mean in userland?  There don't seem to be any immediate problems
> > for genassym.c or any other file in the kernel from including <sys/bus.h>
> > unconditionally in <net/if_var.h>.  However, the pollution may be harmful
> ...
> The problem is that the newbus foo_if.h files don't exist when genassym
> is compiled and used.  sys/bus.h needs bus_if.h and device_if.h, hence
> the breakage.

I see.  This is a bug in the dependencies for genassym.o and .depend.
"make depend" creates *_if.h but it also creates genassym.o.  There aren't
enough dependencies so the order is mostly accidental.  genassym.o happens
to get created first, so it doesn't compile unless *_if.h already exist.

Bruce