Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

Cross-merge networking fixes after downstream PR (net-7.2-rc8).

No conflicts.

Adjacent changes:

drivers/net/ethernet/wangxun/ngbe/ngbe_main.c
  5f3a13e0bb5e ("net: ngbe: fix NULL pointer dereference in non-MSI-X interrupt enabling")
  d661abdc30c2 ("net: ngbe: correct misleading interrupt comment")

drivers/net/ipvlan/ipvlan_main.c
  e16e960d55a4 ("ipvlan: inherit needed_headroom and needed_tailroom from phy_dev")
  00a40d809207 ("ipvlan: Support per-netns netdev unregistration.")

Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 29 insertions, 0 deletions

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index fd688e1f879f..604cc51dfd9b 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -741,6 +741,35 @@ out_unlock:
 	spin_unlock_bh(&fnhe_lock);
 }
 
+/* Update the PMTU of an exception when:
+ * - the new MTU of the first hop becomes smaller than the PMTU
+ * - the old MTU was the same as the PMTU, and it limited discovery of
+ *   larger MTUs on the path. With that limit raised, we can now
+ *   discover larger MTUs
+ * A special case is locked exceptions, for which the PMTU is smaller
+ * than the minimal accepted PMTU:
+ * - if the new MTU is greater than the PMTU, don't make any change
+ * - otherwise, unlock and set PMTU
+ *
+ * fnhe_lock keeps fnhe_pmtu and fnhe_mtu_locked consistent against
+ * update_or_create_fnhe(), which sets both under the same lock.
+ */
+void fnhe_update_pmtu(struct fib_nh_exception *fnhe, u32 new, u32 orig)
+{
+	spin_lock_bh(&fnhe_lock);
+
+	if (fnhe->fnhe_mtu_locked) {
+		if (new <= fnhe->fnhe_pmtu) {
+			fnhe->fnhe_pmtu = new;
+			fnhe->fnhe_mtu_locked = false;
+		}
+	} else if (new < fnhe->fnhe_pmtu || orig == fnhe->fnhe_pmtu) {
+		fnhe->fnhe_pmtu = new;
+	}
+
+	spin_unlock_bh(&fnhe_lock);
+}
+
 static void __ip_do_redirect(struct rtable *rt, struct sk_buff *skb, struct flowi4 *fl4,
 			     bool kill_route)
 {