Re: RFC: [2.6 patch] disallow modular IPv6

From: Adrian Bunk
Date: Sun Sep 28 2003 - 18:25:16 EST


On Sun, Sep 28, 2003 at 08:18:42PM -0300, Arnaldo Carvalho de Melo wrote:
> Em Mon, Sep 29, 2003 at 12:59:41AM +0200, Adrian Bunk escreveu:
> > It seems modular IPv6 doesn't work 100% reliable, e.g. after looking at
> > the code it doesn't seem to be a good idea to compile a kernel without
> > IPv6 support and later build and install IPv6 modules. Is there a great
> > need for modular IPv6 or is the patch below to disallow modular IPv6 OK?
>
> Please, don't... We're going in the all modules direction, not the other
> way around, distro (general purpose) kernels would get big bloat in the
> static kernel.

E.g. from include/net/tcp.h:

<-- snip -->

...
struct tcp_skb_cb {
union {
struct inet_skb_parm h4;
#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
struct inet6_skb_parm h6;
#endif
} header; /* For incoming frames */
...

<-- snip -->

This is broken since it's legal to compile a module much later than the
kernel.

If modular IPv6 is allowed, the #if has to be removed, and the struct
will be larger in the case IPv6 is never be used.

> - Arnaldo

cu
Adrian

--

"Is there not promise of rain?" Ling Tan asked suddenly out
of the darkness. There had been need of rain for many days.
"Only a promise," Lao Er said.
Pearl S. Buck - Dragon Seed

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