2005-09-10 20:19:32

by Mika Kukkonen

[permalink] [raw]
Subject: [PATCH] Fix allnoconfig build with gcc4

It seems that git commit 20380731bc2897f2952ae055420972ded4cd786e breaks
allnoconfig build with gcc4:

CC init/main.o
In file included from include/linux/netdevice.h:29,
from include/net/sock.h:48,
from init/main.c:50:
include/linux/if_ether.h:114: error: array type has incomplete element type

The "normal" fix of replacing foo[] with *foo would is not trivial, but
simply removing the offending line is.

Signed-off-by: Mika Kukkonen <[email protected]>

Index: linux-2.6/include/linux/if_ether.h
===================================================================
--- linux-2.6.orig/include/linux/if_ether.h
+++ linux-2.6/include/linux/if_ether.h
@@ -111,7 +111,6 @@ static inline struct ethhdr *eth_hdr(con
return (struct ethhdr *)skb->mac.raw;
}

-extern struct ctl_table ether_table[];
#endif

#endif /* _LINUX_IF_ETHER_H */


2005-09-10 21:00:15

by Linus Torvalds

[permalink] [raw]
Subject: Re: [PATCH] Fix allnoconfig build with gcc4



On Sat, 10 Sep 2005 [email protected] wrote:
>
> It seems that git commit 20380731bc2897f2952ae055420972ded4cd786e breaks
> allnoconfig build with gcc4:
>
> CC init/main.o
> In file included from include/linux/netdevice.h:29,
> from include/net/sock.h:48,
> from init/main.c:50:
> include/linux/if_ether.h:114: error: array type has incomplete element type
>
> The "normal" fix of replacing foo[] with *foo would is not trivial, but
> simply removing the offending line is.
>
> Signed-off-by: Mika Kukkonen <[email protected]>

No, this would cause a compile error if CONFIG_NET and CONFIG_SYSCTL is
enabled (because sysctl_net.c needs that declaration).

So the correct solution is apparently either one of

- always declare an empty "struct ctl_table" regardless of whether SYSCTL
is enabled or not.

This might be a good idea, since it probably allows more code to be
compiled without checking for CONFIG_SYSCTL.

- put the ether_table[] declaration inside a #ifdef CONFIG_SYSCTL.

Maybe somebody else has a stronger opinion than I do about which of these
is the right solution.

Linus

2005-09-11 17:23:47

by Mika Kukkonen

[permalink] [raw]
Subject: Re: [PATCH] Fix allnoconfig build with gcc4

On 9/11/05, Linus Torvalds <[email protected]> wrote:
>
>
(...)
> No, this would cause a compile error if CONFIG_NET and CONFIG_SYSCTL
> is enabled (because sysctl_net.c needs that declaration).

Ah yes. I got confused by googling which showed that there are some issues
with these declarations and gcc4 (see for example this thread:
http://gcc.gnu.org/ml/gcc/2005-02/msg00053.html).

> So the correct solution is apparently either one of
>
> - always declare an empty "struct ctl_table" regardless of whether SYSCTL
> is enabled or not.
>
> This might be a good idea, since it probably allows more code to be
> compiled without checking for CONFIG_SYSCTL.
>
> - put the ether_table[] declaration inside a #ifdef CONFIG_SYSCTL.

core_table in include/net/sock.h uses the latter option, so I'll send
you a patch
for that (with better email client).

--MiKu