ip6mr: plug drop_reason to ip6mr_cache_report()

- Check mrt->mroute_sk earlier in the function.

- Use sock_queue_rcv_skb_reason() instead of sock_queue_rcv_skb().
- Use sk_skb_reason_drop() instead of kfree_skb().
  Note that we return -ENOMEM if sock_queue_rcv_skb_reason() failed,
  as the precise error is not really needed for callers.

- Remove one net_warn_ratelimited().

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260430074004.4133602-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 85010ff21c981913e2a5e6096819d55c91f5d714..9d748f4c44e97046fa5acae5042f8bd31e13b66d 100644 (file)
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -1063,10 +1063,14 @@ static void ip6mr_cache_resolve(struct net *net, struct mr_table *mrt,
 static int ip6mr_cache_report(const struct mr_table *mrt, struct sk_buff *pkt,
                              mifi_t mifi, int assert)
 {
+       enum skb_drop_reason reason;
        struct sock *mroute6_sk;
        struct sk_buff *skb;
        struct mrt6msg *msg;
-       int ret;
+
+       mroute6_sk = rcu_dereference(mrt->mroute_sk);
+       if (!mroute6_sk)
+               return -EINVAL;
 
 #ifdef CONFIG_IPV6_PIMSM_V2
        if (assert == MRT6MSG_WHOLEPKT || assert == MRT6MSG_WRMIFWHOLE)
@@ -1136,23 +1140,17 @@ static int ip6mr_cache_report(const struct mr_table *mrt, struct sk_buff *pkt,
        skb->ip_summed = CHECKSUM_UNNECESSARY;
        }
 
-       mroute6_sk = rcu_dereference(mrt->mroute_sk);
-       if (!mroute6_sk) {
-               kfree_skb(skb);
-               return -EINVAL;
-       }
-
        mrt6msg_netlink_event(mrt, skb);
 
        /* Deliver to user space multicast routing algorithms */
-       ret = sock_queue_rcv_skb(mroute6_sk, skb);
+       reason = sock_queue_rcv_skb_reason(mroute6_sk, skb);
 
-       if (ret < 0) {
-               net_warn_ratelimited("mroute6: pending queue full, dropping entries\n");
-               kfree_skb(skb);
+       if (reason) {
+               sk_skb_reason_drop(mroute6_sk, skb, reason);
+               return -ENOMEM;
        }
 
-       return ret;
+       return 0;
 }
 
 /* Queue a packet for resolution. It gets locked cache entry! */