IB/core: Honor port_num while resolving GID for IB link layer

ah_attr contains the port number to which cm_id is bound. However, while
searching for GID table for matching GID entry, the port number is
ignored.

This could cause the wrong GID to be used when the ah_attr is converted to
an AH.
Reviewed-by: Daniel Jurgens <danielj@mellanox.com>
Signed-off-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/core/multicast.c

@@ -724,21 +724,19 @@ int ib_init_ah_from_mcmember(struct ib_device *device, u8 port_num,
 {
 	int ret;
 	u16 gid_index;
-	u8 p;
-
-	if (rdma_protocol_roce(device, port_num)) {
-		ret = ib_find_cached_gid_by_port(device, &rec->port_gid,
-						 gid_type, port_num,
-						 ndev,
-						 &gid_index);
-	} else if (rdma_protocol_ib(device, port_num)) {
-		ret = ib_find_cached_gid(device, &rec->port_gid,
-					 IB_GID_TYPE_IB, NULL, &p,
-					 &gid_index);
-	} else {
-		ret = -EINVAL;
-	}
 
+	/* GID table is not based on the netdevice for IB link layer,
+	 * so ignore ndev during search.
+	 */
+	if (rdma_protocol_ib(device, port_num))
+		ndev = NULL;
+	else if (!rdma_protocol_roce(device, port_num))
+		return -EINVAL;
+
+	ret = ib_find_cached_gid_by_port(device, &rec->port_gid,
+					 gid_type, port_num,
+					 ndev,
+					 &gid_index);
 	if (ret)
 		return ret;