RDMA/cma: Allow accepting requests for multi port rdma device

When IP failover is used between multiple ports of a given rdma device,
allow accepting CM requests from either of the ports.  This is applicable
for IPv4 and IPv6 non link local addressing scheme.

IPv6 link local addresses are bound. IP failover requests for listen
cm_ids bound to specific netdev interfaces cannot be supported.
(Similar to traditional sockets).
Signed-off-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/core/cma.c

@@ -1460,17 +1460,34 @@ static bool cma_protocol_roce(const struct rdma_cm_id *id)
 	return rdma_protocol_roce(device, port_num);
 }
 
+static bool cma_is_req_ipv6_ll(const struct cma_req_info *req)
+{
+	const struct sockaddr *daddr =
+			(const struct sockaddr *)&req->listen_addr_storage;
+	const struct sockaddr_in6 *daddr6 = (const struct sockaddr_in6 *)daddr;
+
+	/* Returns true if the req is for IPv6 link local */
+	return (daddr->sa_family == AF_INET6 &&
+		(ipv6_addr_type(&daddr6->sin6_addr) & IPV6_ADDR_LINKLOCAL));
+}
+
 static bool cma_match_net_dev(const struct rdma_cm_id *id,
 			      const struct net_device *net_dev,
-			      u8 port_num)
+			      const struct cma_req_info *req)
 {
 	const struct rdma_addr *addr = &id->route.addr;
 
 	if (!net_dev)
 		/* This request is an AF_IB request */
-		return (!id->port_num || id->port_num == port_num) &&
+		return (!id->port_num || id->port_num == req->port) &&
 		       (addr->src_addr.ss_family == AF_IB);
 
+	/*
+	 * If the request is not for IPv6 link local, allow matching
+	 * request to any netdevice of the one or multiport rdma device.
+	 */
+	if (!cma_is_req_ipv6_ll(req))
+		return true;
 	/*
 	 * Net namespaces must match, and if the listner is listening
 	 * on a specific netdevice than netdevice must match as well.
@@ -1498,13 +1515,14 @@ static struct rdma_id_private *cma_find_listener(
 	hlist_for_each_entry(id_priv, &bind_list->owners, node) {
 		if (cma_match_private_data(id_priv, ib_event->private_data)) {
 			if (id_priv->id.device == cm_id->device &&
-			    cma_match_net_dev(&id_priv->id, net_dev, req->port))
+			    cma_match_net_dev(&id_priv->id, net_dev, req))
 				return id_priv;
 			list_for_each_entry(id_priv_dev,
 					    &id_priv->listen_list,
 					    listen_list) {
 				if (id_priv_dev->id.device == cm_id->device &&
-				    cma_match_net_dev(&id_priv_dev->id, net_dev, req->port))
+				    cma_match_net_dev(&id_priv_dev->id,
+						      net_dev, req))
 					return id_priv_dev;
 			}
 		}