[PATCH v2 net-next] ipv6: move ip6_dst_hoplimit() to net/ipv6/ip6_output.c

[PATCH v2 net-next] ipv6: move ip6_dst_hoplimit() to net/ipv6/ip6_output.c

[Eric Dumazet]

Move ip6_dst_hoplimit() to net/ipv6/ip6_output.c so that compiler
can (auto)inline it from ip6_xmit().

$ scripts/bloat-o-meter -t vmlinux.0 vmlinux.1
add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-11 (-11)
Function                                     old     new   delta
ip6_xmit                                    1684    1673     -11
Total: Before=29655407, After=29655396, chg -0.00%

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Fernando Fernandez Mancera <fmancera@suse.de>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
---
v2: Resend after IPv6 is no longer a module.
    Added Fernando and Kuniyuki 'Reviewed-by'

 net/ipv6/ip6_output.c  | 21 +++++++++++++++++++++
 net/ipv6/output_core.c | 23 -----------------------
 2 files changed, 21 insertions(+), 23 deletions(-)

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 63abc4fddaee8e9cf2ad2ef0873c963eaea63247..7e92909ab5be3f86b10bf9527e97f3bfe794e9e9 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -259,6 +259,27 @@ bool ip6_autoflowlabel(struct net *net, const struct sock *sk)
 	return inet6_test_bit(AUTOFLOWLABEL, sk);
 }
 
+int ip6_dst_hoplimit(struct dst_entry *dst)
+{
+	int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
+
+	rcu_read_lock();
+	if (hoplimit == 0) {
+		struct net_device *dev = dst_dev_rcu(dst);
+		struct inet6_dev *idev;
+
+		idev = __in6_dev_get(dev);
+		if (idev)
+			hoplimit = READ_ONCE(idev->cnf.hop_limit);
+		else
+			hoplimit = READ_ONCE(dev_net(dev)->ipv6.devconf_all->hop_limit);
+	}
+	rcu_read_unlock();
+
+	return hoplimit;
+}
+EXPORT_SYMBOL(ip6_dst_hoplimit);
+
 /*
  * xmit an sk_buff (used by TCP and SCTP)
  * Note : socket lock is not held for SYNACK packets, but might be modified
diff --git a/net/ipv6/output_core.c b/net/ipv6/output_core.c
index cba1684a3f30ff98517d873ddb8e97f32adc9791..64b1eeb79b572b8b412c60f832c4a7984ac8276f 100644
--- a/net/ipv6/output_core.c
+++ b/net/ipv6/output_core.c
@@ -100,29 +100,6 @@ int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
 }
 EXPORT_SYMBOL(ip6_find_1stfragopt);
 
-#if IS_ENABLED(CONFIG_IPV6)
-int ip6_dst_hoplimit(struct dst_entry *dst)
-{
-	int hoplimit = dst_metric_raw(dst, RTAX_HOPLIMIT);
-
-	rcu_read_lock();
-	if (hoplimit == 0) {
-		struct net_device *dev = dst_dev_rcu(dst);
-		struct inet6_dev *idev;
-
-		idev = __in6_dev_get(dev);
-		if (idev)
-			hoplimit = READ_ONCE(idev->cnf.hop_limit);
-		else
-			hoplimit = READ_ONCE(dev_net(dev)->ipv6.devconf_all->hop_limit);
-	}
-	rcu_read_unlock();
-
-	return hoplimit;
-}
-EXPORT_SYMBOL(ip6_dst_hoplimit);
-#endif
-
 int __ip6_local_out(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
 	ipv6_set_payload_len(ipv6_hdr(skb), skb->len - sizeof(struct ipv6hdr));
-- 
2.53.0.1118.gaef5881109-goog

Re: [PATCH v2 net-next] ipv6: move ip6_dst_hoplimit() to net/ipv6/ip6_output.c

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Tue, 31 Mar 2026 17:47:22 +0000 you wrote:
> Move ip6_dst_hoplimit() to net/ipv6/ip6_output.c so that compiler
> can (auto)inline it from ip6_xmit().
> 
> $ scripts/bloat-o-meter -t vmlinux.0 vmlinux.1
> add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-11 (-11)
> Function                                     old     new   delta
> ip6_xmit                                    1684    1673     -11
> Total: Before=29655407, After=29655396, chg -0.00%
> 
> [...]

Here is the summary with links:
  - [v2,net-next] ipv6: move ip6_dst_hoplimit() to net/ipv6/ip6_output.c
    https://git.kernel.org/netdev/net-next/c/63081dec9e37

You are awesome, thank you!
-- 
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