diff --git a/drivers/firewire/core-device.c b/drivers/firewire/core-device.c
index c91d7179eb96..92b633d643f2 100644
--- a/drivers/firewire/core-device.c
+++ b/drivers/firewire/core-device.c
@@ -127,60 +127,7 @@ int fw_csr_string(const u32 *directory, int key, char *buf, size_t size)
 }
 EXPORT_SYMBOL(fw_csr_string);
 
-static bool is_fw_unit(struct device *dev);
-
-static int match_unit_directory(const u32 *directory, u32 match_flags,
-				const struct ieee1394_device_id *id)
-{
-	struct fw_csr_iterator ci;
-	int key, value, match;
-
-	match = 0;
-	fw_csr_iterator_init(&ci, directory);
-	while (fw_csr_iterator_next(&ci, &key, &value)) {
-		if (key == CSR_VENDOR && value == id->vendor_id)
-			match |= IEEE1394_MATCH_VENDOR_ID;
-		if (key == CSR_MODEL && value == id->model_id)
-			match |= IEEE1394_MATCH_MODEL_ID;
-		if (key == CSR_SPECIFIER_ID && value == id->specifier_id)
-			match |= IEEE1394_MATCH_SPECIFIER_ID;
-		if (key == CSR_VERSION && value == id->version)
-			match |= IEEE1394_MATCH_VERSION;
-	}
-
-	return (match & match_flags) == match_flags;
-}
-
-static int fw_unit_match(struct device *dev, struct device_driver *drv)
-{
-	struct fw_unit *unit = fw_unit(dev);
-	struct fw_device *device;
-	const struct ieee1394_device_id *id;
-
-	/* We only allow binding to fw_units. */
-	if (!is_fw_unit(dev))
-		return 0;
-
-	device = fw_parent_device(unit);
-	id = container_of(drv, struct fw_driver, driver)->id_table;
-
-	for (; id->match_flags != 0; id++) {
-		if (match_unit_directory(unit->directory, id->match_flags, id))
-			return 1;
-
-		/* Also check vendor ID in the root directory. */
-		if ((id->match_flags & IEEE1394_MATCH_VENDOR_ID) &&
-		    match_unit_directory(&device->config_rom[5],
-				IEEE1394_MATCH_VENDOR_ID, id) &&
-		    match_unit_directory(unit->directory, id->match_flags
-				& ~IEEE1394_MATCH_VENDOR_ID, id))
-			return 1;
-	}
-
-	return 0;
-}
-
-static void get_modalias_ids(const u32 *directory, int *id)
+static void get_ids(const u32 *directory, int *id)
 {
 	struct fw_csr_iterator ci;
 	int key, value;
@@ -196,12 +143,54 @@ static void get_modalias_ids(const u32 *directory, int *id)
 	}
 }
 
+static void get_modalias_ids(struct fw_unit *unit, int *id)
+{
+	get_ids(&fw_parent_device(unit)->config_rom[5], id);
+	get_ids(unit->directory, id);
+}
+
+static bool match_ids(const struct ieee1394_device_id *id_table, int *id)
+{
+	int match = 0;
+
+	if (id[0] == id_table->vendor_id)
+		match |= IEEE1394_MATCH_VENDOR_ID;
+	if (id[1] == id_table->model_id)
+		match |= IEEE1394_MATCH_MODEL_ID;
+	if (id[2] == id_table->specifier_id)
+		match |= IEEE1394_MATCH_SPECIFIER_ID;
+	if (id[3] == id_table->version)
+		match |= IEEE1394_MATCH_VERSION;
+
+	return (match & id_table->match_flags) == id_table->match_flags;
+}
+
+static bool is_fw_unit(struct device *dev);
+
+static int fw_unit_match(struct device *dev, struct device_driver *drv)
+{
+	const struct ieee1394_device_id *id_table =
+			container_of(drv, struct fw_driver, driver)->id_table;
+	int id[] = {0, 0, 0, 0};
+
+	/* We only allow binding to fw_units. */
+	if (!is_fw_unit(dev))
+		return 0;
+
+	get_modalias_ids(fw_unit(dev), id);
+
+	for (; id_table->match_flags != 0; id_table++)
+		if (match_ids(id_table, id))
+			return 1;
+
+	return 0;
+}
+
 static int get_modalias(struct fw_unit *unit, char *buffer, size_t buffer_size)
 {
 	int id[] = {0, 0, 0, 0};
 
-	get_modalias_ids(&fw_parent_device(unit)->config_rom[5], id);
-	get_modalias_ids(unit->directory, id);
+	get_modalias_ids(unit, id);
 
 	return snprintf(buffer, buffer_size,
 			"ieee1394:ven%08Xmo%08Xsp%08Xver%08X",