From: Arnaldo Carvalho de Melo <acme@conectiva.com.br>
To: Adrian Bunk <bunk@fs.tum.de>
Cc: "David S. Miller" <davem@redhat.com>,
netdev@oss.sgi.com, pekkas@netcore.fi,
lksctp-developers@lists.sourceforge.net,
linux-kernel@vger.kernel.org
Subject: Re: RFC: [2.6 patch] disallow modular IPv6
Date: Tue, 30 Sep 2003 12:04:31 -0300 [thread overview]
Message-ID: <20030930150430.GA2996@conectiva.com.br> (raw)
In-Reply-To: <20030930133729.GJ295@fs.tum.de>
Em Tue, Sep 30, 2003 at 03:37:29PM +0200, Adrian Bunk escreveu:
> On Mon, Sep 29, 2003 at 10:11:29PM -0700, David S. Miller wrote:
> > On Sun, 28 Sep 2003 21:32:30 -0300
> > Arnaldo Carvalho de Melo <acme@conectiva.com.br> wrote:
> >
> > > Em Mon, Sep 29, 2003 at 02:14:39AM +0200, Adrian Bunk escreveu:
> > > > On Sun, Sep 28, 2003 at 08:39:10PM -0300, Arnaldo Carvalho de Melo wrote:
> > > > What about the following solution (the names and help texts for the
> > > > config options might not be optimal, I hope you understand the
> > > > intention):
> > > >
> > > > config IPV6_SUPPORT
> > > > bool "IPv6 support"
> > > >
> > > > config IPV6_ENABLE
> > > > tristate "enable IPv6"
> > > > depends on IPV6_SUPPORT
> > > >
> > > > IPV6_SUPPORT changes structs etc. and IPV6_ENABLE is responsible for
> > > > ipv6.o .
> > >
> > > Humm, and the idea is? This seems confusing, could you elaborate on why such
> > > scheme is a good thing?
> >
> > I think the idea is totally broken. At first, Adrian comments that
> > changing the layout of structs based upon a config option is broken,
> > then he proposes a config option that does nothing except change the
> > layout of structures.
> >
> > The current situation is perfectly fine.
>
> I did perhaps express my opinion not clearly.
>
> My personal opinions:
>
> It's OK that setting an option to y changes structs or whatever else in
> the kernel.
>
> It's not OK if adding a module changes the layout of structs compiled
> into the kernel.
>
> Modules have many advantages, one advantage is e.g. that they allow
> generic distribution kernels without resulting in huge kernel images.
>
> Another advantage is that you can later add modules to a running kernel,
> you can compile a module for your kernel and insert it without rebooting
> the machine. This is currently not possible with moduler IPv6.
>
> That was my personal opinion.
>
> My opinions seem to be very close to the opinions of David Woodhouse, so
> there's no need to repeat your discussion.
And just for the record, as a matter of taste I'd like to see all #ifdefs in
structs to disappear, look at what I did to struct sock in 2.5 and look at
struct sock (include/net/sock.h) in 2.4: no #ifdefs where there was a ton,
what I disagree is to make IPV6 not to be built as a module, that would harm
generic kernels, what I said was that this has to be fixed properly, this
requires time and we are too late in 2.6 for such bigger changes, as this is
not just #ifdefs in structs, it is #ifdefs in the IPV4 code, etc.
Lets revisit this in 2.7.
- Arnaldo
For the record: I did an audit in 99% of the headers in the linux source tree,
#ifdefs in structs are mostly just for: CONFIG_PROCFS, DEBUG, NETFILTER and
IPV6, and just a few.
next prev parent reply other threads:[~2003-09-30 14:58 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-09-28 22:59 RFC: [2.6 patch] disallow modular IPv6 Adrian Bunk
2003-09-28 23:18 ` Arnaldo Carvalho de Melo
2003-09-28 23:24 ` Adrian Bunk
2003-09-28 23:39 ` Arnaldo Carvalho de Melo
2003-09-28 23:47 ` Arnaldo Carvalho de Melo
2003-09-29 0:14 ` Adrian Bunk
2003-09-29 0:32 ` Arnaldo Carvalho de Melo
2003-09-29 9:02 ` David Woodhouse
2003-09-29 14:15 ` Arnaldo Carvalho de Melo
2003-09-29 14:28 ` Jan Evert van Grootheest
2003-09-29 14:29 ` David Woodhouse
2003-09-29 14:38 ` Valdis.Kletnieks
2003-09-29 14:46 ` David Woodhouse
2003-09-30 5:17 ` David S. Miller
2003-09-30 6:31 ` David Woodhouse
2003-10-01 19:47 ` Guennadi Liakhovetski
2003-09-30 5:11 ` David S. Miller
2003-09-30 13:37 ` Adrian Bunk
2003-09-30 15:04 ` Arnaldo Carvalho de Melo [this message]
2003-10-01 6:39 ` David S. Miller
2003-09-30 5:09 ` David S. Miller
2003-09-30 6:32 ` David Woodhouse
2003-09-30 7:03 ` David S. Miller
2003-09-30 7:39 ` David Woodhouse
2003-09-30 8:08 ` David S. Miller
2003-09-30 8:26 ` David Woodhouse
2003-09-30 8:30 ` David S. Miller
2003-09-30 8:42 ` David Woodhouse
2003-09-30 8:51 ` David S. Miller
2003-09-30 9:14 ` David Woodhouse
2003-09-30 9:17 ` David Woodhouse
2003-09-30 9:24 ` David S. Miller
2003-09-30 9:57 ` Sam Ravnborg
2003-09-30 10:02 ` David Woodhouse
2003-09-30 10:01 ` David S. Miller
2003-09-30 10:14 ` David Woodhouse
2003-09-30 11:39 ` Sam Ravnborg
2003-09-30 13:44 ` Dana Lacoste
2003-09-30 13:50 ` Kai Germaschewski
2003-09-30 15:13 ` Richard Guy Briggs
2003-09-30 14:21 ` Theodore Ts'o
2003-09-30 14:51 ` David Woodhouse
2003-09-30 12:06 ` Olivier Galibert
2003-09-29 6:29 ` Pekka Savola
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