Re: Build error v3.9-rc when CONFIG_IPV6 configured as module

[Johannes Berg <johannes@sipsolutions.net>]

On Mon, 2013-04-15 at 11:02 +0200, Johannes Berg wrote:
> On Sun, 2013-04-14 at 12:45 +0300, Tomas Melin wrote:
> > It seems CONFIG_IPV6 cannot be built as a module, using "m"-option
> > leads to to the following linking error:
> > 
> > net/built-in.o: In function `ieee80211_unregister_hw':
> > (.text+0x10f0e1): undefined reference to `unregister_inet6addr_notifier'
> > net/built-in.o: In function `ieee80211_register_hw':
> > (.text+0x10f610): undefined reference to `register_inet6addr_notifier'
> > make: *** [vmlinux] Error 1
> > 
> > This happens since the caller net/mac80211/main.c is statically built
> > in but net/ipv6/addrconf.c is then built as a module. Is this expected
> > behaviour or should it be fixed?
> > 
> > Configuration:  v3.9-rc6 with defconfig but ipv6 set to be a module
> > instead of built in.
> 
> Oops, I didn't realize that IPv6 could even (still) be built as a
> module. I'll add this to mac80211's Kconfig:
> 	depends on IPV6 || !IPV6
> to fix this.

Hm, actually, that's not sufficient since there are no no-op versions of
these functions when IPv6 isn't built ... needs a bit more.

johannes