[PATCH IPV6 v2 3/4] ipv6: ip6_finish_output2 refactoring

From: Vasily Averin
Date: Fri Jul 09 2021 - 05:05:40 EST


Commonly used dereferences was replaced by variables.

Signed-off-by: Vasily Averin <vvs@xxxxxxxxxxxxx>
---
net/ipv6/ip6_output.c | 29 ++++++++++++++---------------
1 file changed, 14 insertions(+), 15 deletions(-)

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 9418802..9ae3baa 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -83,9 +83,11 @@ static int ip6_finish_output2(struct net *net, struct sock *sk, struct sk_buff *
{
struct dst_entry *dst = skb_dst(skb);
struct net_device *dev = dst->dev;
+ struct inet6_dev *idev = ip6_dst_idev(dst);
unsigned int hh_len = LL_RESERVED_SPACE(dev);
int delta = hh_len - skb_headroom(skb);
- const struct in6_addr *nexthop;
+ const struct in6_addr *daddr, *nexthop;
+ struct ipv6hdr *hdr;
struct neighbour *neigh;
int ret;

@@ -94,18 +96,17 @@ static int ip6_finish_output2(struct net *net, struct sock *sk, struct sk_buff *
skb = skb_expand_head(skb, delta);

if (!skb) {
- IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTDISCARDS);
+ IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS);
return -ENOMEM;
}

- if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr)) {
- struct inet6_dev *idev = ip6_dst_idev(skb_dst(skb));
-
+ hdr = ipv6_hdr(skb);
+ daddr = &hdr->daddr;
+ if (ipv6_addr_is_multicast(daddr)) {
if (!(dev->flags & IFF_LOOPBACK) && sk_mc_loop(sk) &&
((mroute6_is_socket(net, skb) &&
!(IP6CB(skb)->flags & IP6SKB_FORWARDED)) ||
- ipv6_chk_mcast_addr(dev, &ipv6_hdr(skb)->daddr,
- &ipv6_hdr(skb)->saddr))) {
+ ipv6_chk_mcast_addr(dev, daddr, &hdr->saddr))) {
struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);

/* Do not check for IFF_ALLMULTI; multicast routing
@@ -116,7 +117,7 @@ static int ip6_finish_output2(struct net *net, struct sock *sk, struct sk_buff *
net, sk, newskb, NULL, newskb->dev,
dev_loopback_xmit);

- if (ipv6_hdr(skb)->hop_limit == 0) {
+ if (hdr->hop_limit == 0) {
IP6_INC_STATS(net, idev,
IPSTATS_MIB_OUTDISCARDS);
kfree_skb(skb);
@@ -125,9 +126,7 @@ static int ip6_finish_output2(struct net *net, struct sock *sk, struct sk_buff *
}

IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_OUTMCAST, skb->len);
-
- if (IPV6_ADDR_MC_SCOPE(&ipv6_hdr(skb)->daddr) <=
- IPV6_ADDR_SCOPE_NODELOCAL &&
+ if (IPV6_ADDR_MC_SCOPE(daddr) <= IPV6_ADDR_SCOPE_NODELOCAL &&
!(dev->flags & IFF_LOOPBACK)) {
kfree_skb(skb);
return 0;
@@ -142,10 +141,10 @@ static int ip6_finish_output2(struct net *net, struct sock *sk, struct sk_buff *
}

rcu_read_lock_bh();
- nexthop = rt6_nexthop((struct rt6_info *)dst, &ipv6_hdr(skb)->daddr);
- neigh = __ipv6_neigh_lookup_noref(dst->dev, nexthop);
+ nexthop = rt6_nexthop((struct rt6_info *)dst, daddr);
+ neigh = __ipv6_neigh_lookup_noref(dev, nexthop);
if (unlikely(!neigh))
- neigh = __neigh_create(&nd_tbl, nexthop, dst->dev, false);
+ neigh = __neigh_create(&nd_tbl, nexthop, dev, false);
if (!IS_ERR(neigh)) {
sock_confirm_neigh(skb, neigh);
ret = neigh_output(neigh, skb, false);
@@ -154,7 +153,7 @@ static int ip6_finish_output2(struct net *net, struct sock *sk, struct sk_buff *
}
rcu_read_unlock_bh();

- IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
+ IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTNOROUTES);
kfree_skb(skb);
return -EINVAL;
}
--
1.8.3.1