[PATCH net-next v5 06/11] wireguard: socket: convert send{4,6} to use a noref dst when possible
From: Marek Mietus <hidden>
Date: 2026-01-13 16:33:54
Subsystem:
networking drivers, the rest, wireguard secure network tunnel · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Jason A. Donenfeld
send{4,6} unnecessarily reference the dst_entry from the
dst_cache when interacting with the cache.
Reduce this overhead by avoiding the redundant refcount increments.
This is only possible in flows where the cache is used. Otherwise, we
fall-back to a referenced dst.
These changes are safe as both ipv4 and ip6 support noref xmit under RCU
which is already the case for the wireguard send{4,6} functions.
Signed-off-by: Marek Mietus <redacted>
---
drivers/net/wireguard/socket.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/drivers/net/wireguard/socket.c b/drivers/net/wireguard/socket.c
index ee7d9c675909..b311965269a1 100644
--- a/drivers/net/wireguard/socket.c
+++ b/drivers/net/wireguard/socket.c@@ -46,7 +46,7 @@ static int send4(struct wg_device *wg, struct sk_buff *skb, fl.fl4_sport = inet_sk(sock)->inet_sport; if (cache) - rt = dst_cache_get_ip4(cache, &fl.saddr); + rt = dst_cache_get_ip4_rcu(cache, &fl.saddr); if (!rt) { security_sk_classify_flow(sock, flowi4_to_flowi_common(&fl));
@@ -78,14 +78,15 @@ static int send4(struct wg_device *wg, struct sk_buff *skb, goto err; } if (cache) - dst_cache_set_ip4(cache, &rt->dst, fl.saddr); + dst_cache_steal_ip4(cache, &rt->dst, fl.saddr); } skb->ignore_df = 1; udp_tunnel_xmit_skb(rt, sock, skb, fl.saddr, fl.daddr, ds, ip4_dst_hoplimit(&rt->dst), 0, fl.fl4_sport, fl.fl4_dport, false, false, 0); - ip_rt_put(rt); + if (!cache) + ip_rt_put(rt); goto out; err:
@@ -127,7 +128,7 @@ static int send6(struct wg_device *wg, struct sk_buff *skb, fl.fl6_sport = inet_sk(sock)->inet_sport; if (cache) - dst = dst_cache_get_ip6(cache, &fl.saddr); + dst = dst_cache_get_ip6_rcu(cache, &fl.saddr); if (!dst) { security_sk_classify_flow(sock, flowi6_to_flowi_common(&fl));
@@ -146,14 +147,15 @@ static int send6(struct wg_device *wg, struct sk_buff *skb, goto err; } if (cache) - dst_cache_set_ip6(cache, dst, &fl.saddr); + dst_cache_steal_ip6(cache, dst, &fl.saddr); } skb->ignore_df = 1; udp_tunnel6_xmit_skb(dst, sock, skb, skb->dev, &fl.saddr, &fl.daddr, ds, ip6_dst_hoplimit(dst), 0, fl.fl6_sport, fl.fl6_dport, false, 0); - dst_release(dst); + if (!cache) + dst_release(dst); goto out; err:
--
2.51.0