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From:   Vasily Averin <vvs@virtuozzo.com>
Subject: [PATCH IPV6 v2 4/4] ipv6: ip6_xmit refactoring
To:     "David S. Miller" <davem@davemloft.net>,
        Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
        David Ahern <dsahern@kernel.org>,
        Jakub Kicinski <kuba@kernel.org>,
        Eric Dumazet <eric.dumazet@gmail.com>
Cc:     netdev@vger.kernel.org, linux-kernel@vger.kernel.org
References: <1cbf3c7b-455e-f3a5-cc2c-c18ce8be4ce1@gmail.com>
 <cover.1625818825.git.vvs@virtuozzo.com>
Message-ID: <a3120d9c-e6c6-13d0-31ce-6f9a9d8f57a6@virtuozzo.com>
Date:   Fri, 9 Jul 2021 12:05:56 +0300
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Commonly used dereferences was replaced by variables.

Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
---
 net/ipv6/ip6_output.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 9ae3baa..5e33429 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -273,6 +273,8 @@ int ip6_xmit(const struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
 	const struct ipv6_pinfo *np = inet6_sk(sk);
 	struct in6_addr *first_hop = &fl6->daddr;
 	struct dst_entry *dst = skb_dst(skb);
+	struct net_device *dev = dst->dev;
+	struct inet6_dev *idev = ip6_dst_idev(dst);
 	unsigned int head_room;
 	struct ipv6hdr *hdr;
 	u8  proto = fl6->flowi6_proto;
@@ -280,7 +282,7 @@ int ip6_xmit(const struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
 	int delta, hlimit = -1;
 	u32 mtu;
 
-	head_room = sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dst->dev);
+	head_room = sizeof(struct ipv6hdr) + LL_RESERVED_SPACE(dev);
 	if (opt)
 		head_room += opt->opt_nflen + opt->opt_flen;
 
@@ -288,8 +290,7 @@ int ip6_xmit(const struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
 	if (unlikely(delta > 0)) {
 		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 -ENOBUFS;
 		}
 	}
@@ -333,8 +334,7 @@ int ip6_xmit(const struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
 
 	mtu = dst_mtu(dst);
 	if ((skb->len <= mtu) || skb->ignore_df || skb_is_gso(skb)) {
-		IP6_UPD_PO_STATS(net, ip6_dst_idev(skb_dst(skb)),
-			      IPSTATS_MIB_OUT, skb->len);
+		IP6_UPD_PO_STATS(net, idev, IPSTATS_MIB_OUT, skb->len);
 
 		/* if egress device is enslaved to an L3 master device pass the
 		 * skb to its handler for processing
@@ -347,17 +347,17 @@ int ip6_xmit(const struct sock *sk, struct sk_buff *skb, struct flowi6 *fl6,
 		 * we promote our socket to non const
 		 */
 		return NF_HOOK(NFPROTO_IPV6, NF_INET_LOCAL_OUT,
-			       net, (struct sock *)sk, skb, NULL, dst->dev,
+			       net, (struct sock *)sk, skb, NULL, dev,
 			       dst_output);
 	}
 
-	skb->dev = dst->dev;
+	skb->dev = dev;
 	/* ipv6_local_error() does not require socket lock,
 	 * we promote our socket to non const
 	 */
 	ipv6_local_error((struct sock *)sk, EMSGSIZE, fl6, mtu);
 
-	IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_FRAGFAILS);
+	IP6_INC_STATS(net, idev, IPSTATS_MIB_FRAGFAILS);
 	kfree_skb(skb);
 	return -EMSGSIZE;
 }
-- 
1.8.3.1