| Message ID | 20231122071924.8302-1-chentao@kylinos.cn (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [v3] ipv6: Correct/silence an endian warning in ip6_multipath_l3_keys | expand |
On Wed, Nov 22, 2023 at 03:19:24PM +0800, Kunwu Chan wrote: > net/ipv6/route.c:2332:39: warning: incorrect type in assignment (different base types) > net/ipv6/route.c:2332:39: expected unsigned int [usertype] flow_label > net/ipv6/route.c:2332:39: got restricted __be32 Can you expain why you think the __force cast is the correct thing to do here?
Hi Christoph, Thanks for your reply. I also can't guarantee that it's the right thing to do. Just wanted to dispel this warning. If you have any better way, please let me know. On 2023/11/22 15:23, Christoph Hellwig wrote: > On Wed, Nov 22, 2023 at 03:19:24PM +0800, Kunwu Chan wrote: >> net/ipv6/route.c:2332:39: warning: incorrect type in assignment (different base types) >> net/ipv6/route.c:2332:39: expected unsigned int [usertype] flow_label >> net/ipv6/route.c:2332:39: got restricted __be32 > > Can you expain why you think the __force cast is the correct thing to do > here?
On Wed, Nov 22, 2023 at 05:04:49PM +0800, Kunwu Chan wrote: > Hi Christoph, > Thanks for your reply. > I also can't guarantee that it's the right thing to do. Just wanted to > dispel this warning. If you have any better way, please let me know. The most likely reason is that it needs an endianess conversion. I don't know the answer either, but actually spending a few minutes trying to understand the code should allow you to find it out quickly. Removing a warning for it's own sake when you don't understand it is never a good idea.
On 11/22/23 1:06 AM, Christoph Hellwig wrote: > On Wed, Nov 22, 2023 at 05:04:49PM +0800, Kunwu Chan wrote: >> Hi Christoph, >> Thanks for your reply. >> I also can't guarantee that it's the right thing to do. Just wanted to >> dispel this warning. If you have any better way, please let me know. > > The most likely reason is that it needs an endianess conversion. I > don't know the answer either, but actually spending a few minutes > trying to understand the code should allow you to find it out quickly. > > Removing a warning for it's own sake when you don't understand it is > never a good idea. > We should be able to set flow_label to __be32 in flow_dissector_key_tags (and remove a couple ntohl). Tom: any reason not to do that?
diff --git a/net/ipv6/route.c b/net/ipv6/route.c index b132feae3393..1fdae8d71339 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -2329,7 +2329,7 @@ static void ip6_multipath_l3_keys(const struct sk_buff *skb, } else { keys->addrs.v6addrs.src = key_iph->saddr; keys->addrs.v6addrs.dst = key_iph->daddr; - keys->tags.flow_label = ip6_flowlabel(key_iph); + keys->tags.flow_label = (__force u32)ip6_flowlabel(key_iph); keys->basic.ip_proto = key_iph->nexthdr; } }
net/ipv6/route.c:2332:39: warning: incorrect type in assignment (different base types) net/ipv6/route.c:2332:39: expected unsigned int [usertype] flow_label net/ipv6/route.c:2332:39: got restricted __be32 Fixes: 23aebdacb05d ("ipv6: Compute multipath hash for ICMP errors from offending packet") Suggested-by: Eric Dumazet <edumazet@google.com> Suggested-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Kunwu Chan <chentao@kylinos.cn> --- net/ipv6/route.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)