Re: finishing the if.h/if_var.h split

From: John Baldwin (jhb_at_FreeBSD.org)
Date: 09/30/03

  • Next message: John Baldwin: "Re: adding if_dev member to struct ifnet" 
    Date: Tue, 30 Sep 2003 10:33:40 -0400 (EDT)
To: Bruce Evans <bde@zeta.org.au>

    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/
_______________________________________________
freebsd-arch@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-arch
To unsubscribe, send any mail to "freebsd-arch-unsubscribe@freebsd.org"
  • Next message: John Baldwin: "Re: adding if_dev member to struct ifnet"