Date: Tue, 30 Sep 2003 10:33:40 -0400 (EDT) From: John Baldwin <jhb@FreeBSD.org> To: Bruce Evans <bde@zeta.org.au> Cc: net@freebsd.org Subject: Re: finishing the if.h/if_var.h split Message-ID: <XFMail.20030930103340.jhb@FreeBSD.org> In-Reply-To: <20030930172536.U3713@gamplex.bde.org>
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On 30-Sep-2003 Bruce Evans wrote: > On Mon, 29 Sep 2003, Brooks Davis wrote: > >> Six years and eight months ago, net/if.h was split into if.h and >> if_var.h. At the time, if_var.h was included at the end if if.h as >> follows (this is the current code, but it's equivalent): >> >> #ifdef _KERNEL >> struct thread; >> >> /* XXX - this should go away soon. */ >> #include <net/if_var.h> >> #endif >> >> 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. >> 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 > for userland. In fact, including <sys/bus.h> would just not work for > userland, since the declaration of device_t is only made in the _KERNEL > case, so use of it in struct ifnet (which is exported to userland for > some reason) would be a syntax error in userland whether or not > <sys/bus.h> is included. Oops, <net/if.h> doesn't include <net/if_var.h> > in the !_KERNEL case, so the problem is a little different... 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. -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/
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