From owner-freebsd-net@FreeBSD.ORG  Tue Sep 30 08:30:46 2003
Return-Path: <owner-freebsd-net@FreeBSD.ORG>
Delivered-To: freebsd-net@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP
	id B657D16A4BF; Tue, 30 Sep 2003 08:30:46 -0700 (PDT)
Received: from mailman.zeta.org.au (mailman.zeta.org.au [203.26.10.16])
	by mx1.FreeBSD.org (Postfix) with ESMTP
	id E0F9344013; Tue, 30 Sep 2003 08:30:41 -0700 (PDT)
	(envelope-from bde@zeta.org.au)
Received: from gamplex.bde.org (katana.zip.com.au [61.8.7.246])
	by mailman.zeta.org.au (8.9.3p2/8.8.7) with ESMTP id BAA17679;
	Wed, 1 Oct 2003 01:30:30 +1000
Date: Wed, 1 Oct 2003 01:29:07 +1000 (EST)
From: Bruce Evans <bde@zeta.org.au>
X-X-Sender: bde@gamplex.bde.org
To: John Baldwin <jhb@freebsd.org>
In-Reply-To: <XFMail.20030930103340.jhb@FreeBSD.org>
Message-ID: <20031001011119.U1245@gamplex.bde.org>
References: <XFMail.20030930103340.jhb@FreeBSD.org>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
cc: arch@freebsd.org
cc: net@freebsd.org
Subject: Re: finishing the if.h/if_var.h split
X-BeenThere: freebsd-net@freebsd.org
X-Mailman-Version: 2.1.1
Precedence: list
List-Id: Networking and TCP/IP with FreeBSD <freebsd-net.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-net>,
	<mailto:freebsd-net-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-net>
List-Post: <mailto:freebsd-net@freebsd.org>
List-Help: <mailto:freebsd-net-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-net>,
	<mailto:freebsd-net-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 30 Sep 2003 15:30:46 -0000

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