NFS: Set default port for NFSv4, with support for AF_INET6

Create a helper function to set the default NFS port for NFSv4 mount
points.  The helper supports both AF_INET and AF_INET6 family addresses.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/super.c

@@ -1595,6 +1595,28 @@ static void nfs4_fill_super(struct super_block *sb)
 	nfs_initialise_sb(sb);
 }
 
+/*
+ * If the user didn't specify a port, set the port number to
+ * the NFS version 4 default port.
+ */
+static void nfs4_default_port(struct sockaddr *sap)
+{
+	switch (sap->sa_family) {
+	case AF_INET: {
+		struct sockaddr_in *ap = (struct sockaddr_in *)sap;
+		if (ap->sin_port == 0)
+			ap->sin_port = htons(NFS_PORT);
+		break;
+	}
+	case AF_INET6: {
+		struct sockaddr_in6 *ap = (struct sockaddr_in6 *)sap;
+		if (ap->sin6_port == 0)
+			ap->sin6_port = htons(NFS_PORT);
+		break;
+	}
+	}
+}
+
 /*
  * Validate NFSv4 mount options
  */
@@ -1628,12 +1650,13 @@ static int nfs4_validate_mount_data(void *options,
 				   data->host_addr,
 				   sizeof(args->nfs_server.address)))
 			return -EFAULT;
-		if (args->nfs_server.address.sin_port == 0)
-			args->nfs_server.address.sin_port = htons(NFS_PORT);
 		if (!nfs_verify_server_address((struct sockaddr *)
 						&args->nfs_server.address))
 			goto out_no_address;
 
+		nfs4_default_port((struct sockaddr *)
+				  &args->nfs_server.address);
+
 		switch (data->auth_flavourlen) {
 		case 0:
 			args->auth_flavors[0] = RPC_AUTH_UNIX;
@@ -1687,12 +1710,13 @@ static int nfs4_validate_mount_data(void *options,
 		if (nfs_parse_mount_options((char *)options, args) == 0)
 			return -EINVAL;
 
-		if (args->nfs_server.address.sin_port == 0)
-			args->nfs_server.address.sin_port = htons(NFS_PORT);
 		if (!nfs_verify_server_address((struct sockaddr *)
 						&args->nfs_server.address))
 			return -EINVAL;
 
+		nfs4_default_port((struct sockaddr *)
+				  &args->nfs_server.address);
+
 		switch (args->auth_flavor_len) {
 		case 0:
 			args->auth_flavors[0] = RPC_AUTH_UNIX;