On Thu, Sep 20, 2012 at 09:14:02AM +0200, Patrick McHardy wrote:

On Tue, 11 Sep 2012, Patrick McHardy wrote:

quoted

On Fri, 7 Sep 2012, Fengguang Wu wrote:

quoted

Hi Patrick,

FYI, there are new compile warnings show up in

tree:   git://gitorious.org/linux-can/linux-can-next master
head:   bbe660a7ddf32dfe80753c6722e141bf7e4bf5d8
commit: 4cdd34084d539c758d00c5dc7bf95db2e4f2bc70 [239/293]
netfilter: nf_conntrack_ipv6: improve fragmentation handling
config: avr32-atngw100_defconfig (attached as .config)

All error/warnings:

net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c: In function
'__ipv6_conntrack_in':
net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c:231: warning:
passing argument 4 of 'NF_HOOK_THRESH' discards qualifiers from
pointer target type
net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c:231: warning:
passing argument 5 of 'NF_HOOK_THRESH' discards qualifiers from
pointer target type

Thanks, I'll look into this.

It seems the cure for this is worse than the problem. The code
currently casts the const struct net_device pointer to non-const
for the NF_HOOK_THRES call. To avoid the cast we'd have to change
all netfilter hooks to take a non-const pointer. The alternative
would be to change the NF_HOOK functions to also take a const struct
net_device pointer, but that would require the same cast to non-const
for nf_queue, which uses dev_hold() and dev_put(), so this would
effectively just move the warning to a different place.

nf_queue is a quite special case, normally netfilter hooks shouln't
be changing anything on the net_device, so I don't want to unconstify
the arguments.

The compiler actually shouldn't warn about this since its an explicit
cast. I know some older versions of gcc did this, but there's no
warning with current versions of gcc and the same casts are already
present
in other parts of IPv6 conntrack.

Yes, the avr32 builds are using an old gcc. Please ignore this
warning. I'll teach the build system to ignore this class of warning
on older gcc.

Thanks,
Fengguang