1 files changed, 15 insertions, 22 deletions

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index fe8e22aff7d2..b767a336ad98 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -514,30 +514,14 @@ __lookup_addr(struct pm_nl_pernet *pernet, const struct mptcp_addr_info *info,
 	struct mptcp_pm_addr_entry *entry;
 
 	list_for_each_entry(entry, &pernet->local_addr_list, list) {
-		if ((!lookup_by_id && mptcp_addresses_equal(&entry->addr, info, true)) ||
+		if ((!lookup_by_id &&
+		     mptcp_addresses_equal(&entry->addr, info, entry->addr.port)) ||
 		    (lookup_by_id && entry->addr.id == info->id))
 			return entry;
 	}
 	return NULL;
 }
 
-static int
-lookup_id_by_addr(const struct pm_nl_pernet *pernet, const struct mptcp_addr_info *addr)
-{
-	const struct mptcp_pm_addr_entry *entry;
-	int ret = -1;
-
-	rcu_read_lock();
-	list_for_each_entry(entry, &pernet->local_addr_list, list) {
-		if (mptcp_addresses_equal(&entry->addr, addr, entry->addr.port)) {
-			ret = entry->addr.id;
-			break;
-		}
-	}
-	rcu_read_unlock();
-	return ret;
-}
-
 static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 {
 	struct sock *sk = (struct sock *)msk;
@@ -555,13 +539,22 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 
 	/* do lazy endpoint usage accounting for the MPC subflows */
 	if (unlikely(!(msk->pm.status & BIT(MPTCP_PM_MPC_ENDPOINT_ACCOUNTED))) && msk->first) {
+		struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(msk->first);
+		struct mptcp_pm_addr_entry *entry;
 		struct mptcp_addr_info mpc_addr;
-		int mpc_id;
+		bool backup = false;
 
 		local_address((struct sock_common *)msk->first, &mpc_addr);
-		mpc_id = lookup_id_by_addr(pernet, &mpc_addr);
-		if (mpc_id >= 0)
-			__clear_bit(mpc_id, msk->pm.id_avail_bitmap);
+		rcu_read_lock();
+		entry = __lookup_addr(pernet, &mpc_addr, false);
+		if (entry) {
+			__clear_bit(entry->addr.id, msk->pm.id_avail_bitmap);
+			backup = !!(entry->flags & MPTCP_PM_ADDR_FLAG_BACKUP);
+		}
+		rcu_read_unlock();
+
+		if (backup)
+			mptcp_pm_send_ack(msk, subflow, true, backup);
 
 		msk->pm.status |= BIT(MPTCP_PM_MPC_ENDPOINT_ACCOUNTED);
 	}