net-ipv6: Fix alleged compiler warning in ipv6_exthdrs_len()
It was reported that Commit 299603e8370a93dd5d8e8d800f0dff1ce2c53d36
("net-gro: Prepare GRO stack for the upcoming tunneling support")
triggered a compiler warning in ipv6_exthdrs_len():
net/ipv6/ip6_offload.c: In function ‘ipv6_gro_complete’:
net/ipv6/ip6_offload.c:178:24: warning: ‘optlen’ may be used uninitialized in this function [-Wmaybe-u
opth = (void *)opth + optlen;
^
net/ipv6/ip6_offload.c:164:22: note: ‘optlen’ was declared here
int len = 0, proto, optlen;
^
Note that there was no real bug here - optlen was never uninitialized
before use. (Was the version of gcc I used smarter to not complain?)
Reported-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: H.K. Jerry Chu <hkchu@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c
index 08861f1..6fb4162 100644
--- a/net/ipv6/ip6_offload.c
+++ b/net/ipv6/ip6_offload.c
@@ -160,8 +160,8 @@
static int ipv6_exthdrs_len(struct ipv6hdr *iph,
const struct net_offload **opps)
{
- struct ipv6_opt_hdr *opth = NULL;
- int len = 0, optlen = 0, proto;
+ struct ipv6_opt_hdr *opth = (void *)iph;
+ int len = 0, proto, optlen = sizeof(*iph);
proto = iph->nexthdr;
for (;;) {
@@ -172,12 +172,8 @@
if (!((*opps)->flags & INET6_PROTO_GSO_EXTHDR))
break;
}
- if (opth == NULL) {
- opth = (void *)(iph+1);
- } else {
- optlen = ipv6_optlen(opth);
- opth = (void *)opth + optlen;
- }
+ opth = (void *)opth + optlen;
+ optlen = ipv6_optlen(opth);
len += optlen;
proto = opth->nexthdr;
}