diff --git a/security/tomoyo/file.c b/security/tomoyo/file.c
index 3323802..4259e0a 100644
--- a/security/tomoyo/file.c
+++ b/security/tomoyo/file.c
@@ -49,6 +49,9 @@
 	[TOMOYO_TYPE_CHGRP]      = "chgrp",
 };
 
+/*
+ * Mapping table from "enum tomoyo_path_acl_index" to "enum tomoyo_mac_index".
+ */
 static const u8 tomoyo_p2mac[TOMOYO_MAX_PATH_OPERATION] = {
 	[TOMOYO_TYPE_EXECUTE]    = TOMOYO_MAC_FILE_EXECUTE,
 	[TOMOYO_TYPE_READ]       = TOMOYO_MAC_FILE_OPEN,
@@ -63,17 +66,27 @@
 	[TOMOYO_TYPE_UMOUNT]     = TOMOYO_MAC_FILE_UMOUNT,
 };
 
+/*
+ * Mapping table from "enum tomoyo_mkdev_acl_index" to "enum tomoyo_mac_index".
+ */
 static const u8 tomoyo_pnnn2mac[TOMOYO_MAX_MKDEV_OPERATION] = {
 	[TOMOYO_TYPE_MKBLOCK] = TOMOYO_MAC_FILE_MKBLOCK,
 	[TOMOYO_TYPE_MKCHAR]  = TOMOYO_MAC_FILE_MKCHAR,
 };
 
+/*
+ * Mapping table from "enum tomoyo_path2_acl_index" to "enum tomoyo_mac_index".
+ */
 static const u8 tomoyo_pp2mac[TOMOYO_MAX_PATH2_OPERATION] = {
 	[TOMOYO_TYPE_LINK]       = TOMOYO_MAC_FILE_LINK,
 	[TOMOYO_TYPE_RENAME]     = TOMOYO_MAC_FILE_RENAME,
 	[TOMOYO_TYPE_PIVOT_ROOT] = TOMOYO_MAC_FILE_PIVOT_ROOT,
 };
 
+/*
+ * Mapping table from "enum tomoyo_path_number_acl_index" to
+ * "enum tomoyo_mac_index".
+ */
 static const u8 tomoyo_pn2mac[TOMOYO_MAX_PATH_NUMBER_OPERATION] = {
 	[TOMOYO_TYPE_CREATE] = TOMOYO_MAC_FILE_CREATE,
 	[TOMOYO_TYPE_MKDIR]  = TOMOYO_MAC_FILE_MKDIR,
@@ -85,41 +98,76 @@
 	[TOMOYO_TYPE_CHGRP]  = TOMOYO_MAC_FILE_CHGRP,
 };
 
+/**
+ * tomoyo_put_name_union - Drop reference on "struct tomoyo_name_union".
+ *
+ * @ptr: Pointer to "struct tomoyo_name_union".
+ *
+ * Returns nothing.
+ */
 void tomoyo_put_name_union(struct tomoyo_name_union *ptr)
 {
-	if (!ptr)
-		return;
-	if (ptr->is_group)
-		tomoyo_put_group(ptr->group);
-	else
-		tomoyo_put_name(ptr->filename);
+	tomoyo_put_group(ptr->group);
+	tomoyo_put_name(ptr->filename);
 }
 
+/**
+ * tomoyo_compare_name_union - Check whether a name matches "struct tomoyo_name_union" or not.
+ *
+ * @name: Pointer to "struct tomoyo_path_info".
+ * @ptr:  Pointer to "struct tomoyo_name_union".
+ *
+ * Returns "struct tomoyo_path_info" if @name matches @ptr, NULL otherwise.
+ */
 const struct tomoyo_path_info *
 tomoyo_compare_name_union(const struct tomoyo_path_info *name,
 			  const struct tomoyo_name_union *ptr)
 {
-	if (ptr->is_group)
+	if (ptr->group)
 		return tomoyo_path_matches_group(name, ptr->group);
 	if (tomoyo_path_matches_pattern(name, ptr->filename))
 		return ptr->filename;
 	return NULL;
 }
 
+/**
+ * tomoyo_put_number_union - Drop reference on "struct tomoyo_number_union".
+ *
+ * @ptr: Pointer to "struct tomoyo_number_union".
+ *
+ * Returns nothing.
+ */
 void tomoyo_put_number_union(struct tomoyo_number_union *ptr)
 {
-	if (ptr && ptr->is_group)
-		tomoyo_put_group(ptr->group);
+	tomoyo_put_group(ptr->group);
 }
 
+/**
+ * tomoyo_compare_number_union - Check whether a value matches "struct tomoyo_number_union" or not.
+ *
+ * @value: Number to check.
+ * @ptr:   Pointer to "struct tomoyo_number_union".
+ *
+ * Returns true if @value matches @ptr, false otherwise.
+ */
 bool tomoyo_compare_number_union(const unsigned long value,
 				 const struct tomoyo_number_union *ptr)
 {
-	if (ptr->is_group)
+	if (ptr->group)
 		return tomoyo_number_matches_group(value, value, ptr->group);
 	return value >= ptr->values[0] && value <= ptr->values[1];
 }
 
+/**
+ * tomoyo_add_slash - Add trailing '/' if needed.
+ *
+ * @buf: Pointer to "struct tomoyo_path_info".
+ *
+ * Returns nothing.
+ *
+ * @buf must be generated by tomoyo_encode() because this function does not
+ * allocate memory for adding '/'.
+ */
 static void tomoyo_add_slash(struct tomoyo_path_info *buf)
 {
 	if (buf->is_dir)
@@ -247,6 +295,18 @@
 				 filename->name, buffer);
 }
 
+/**
+ * tomoyo_check_path_acl - Check permission for path operation.
+ *
+ * @r:   Pointer to "struct tomoyo_request_info".
+ * @ptr: Pointer to "struct tomoyo_acl_info".
+ *
+ * Returns true if granted, false otherwise.
+ *
+ * To be able to use wildcard for domain transition, this function sets
+ * matching entry on success. Since the caller holds tomoyo_read_lock(),
+ * it is safe to set matching entry.
+ */
 static bool tomoyo_check_path_acl(struct tomoyo_request_info *r,
 				  const struct tomoyo_acl_info *ptr)
 {
@@ -261,6 +321,14 @@
 	return false;
 }
 
+/**
+ * tomoyo_check_path_number_acl - Check permission for path number operation.
+ *
+ * @r:   Pointer to "struct tomoyo_request_info".
+ * @ptr: Pointer to "struct tomoyo_acl_info".
+ *
+ * Returns true if granted, false otherwise.
+ */
 static bool tomoyo_check_path_number_acl(struct tomoyo_request_info *r,
 					 const struct tomoyo_acl_info *ptr)
 {
@@ -273,6 +341,14 @@
 					  &acl->name);
 }
 
+/**
+ * tomoyo_check_path2_acl - Check permission for path path operation.
+ *
+ * @r:   Pointer to "struct tomoyo_request_info".
+ * @ptr: Pointer to "struct tomoyo_acl_info".
+ *
+ * Returns true if granted, false otherwise.
+ */
 static bool tomoyo_check_path2_acl(struct tomoyo_request_info *r,
 				   const struct tomoyo_acl_info *ptr)
 {
@@ -284,8 +360,16 @@
 					     &acl->name2);
 }
 
+/**
+ * tomoyo_check_mkdev_acl - Check permission for path number number number operation.
+ *
+ * @r:   Pointer to "struct tomoyo_request_info".
+ * @ptr: Pointer to "struct tomoyo_acl_info".
+ *
+ * Returns true if granted, false otherwise.
+ */
 static bool tomoyo_check_mkdev_acl(struct tomoyo_request_info *r,
-				const struct tomoyo_acl_info *ptr)
+				   const struct tomoyo_acl_info *ptr)
 {
 	const struct tomoyo_mkdev_acl *acl =
 		container_of(ptr, typeof(*acl), head);
@@ -300,13 +384,20 @@
 					  &acl->name);
 }
 
+/**
+ * tomoyo_same_path_acl - Check for duplicated "struct tomoyo_path_acl" entry.
+ *
+ * @a: Pointer to "struct tomoyo_acl_info".
+ * @b: Pointer to "struct tomoyo_acl_info".
+ *
+ * Returns true if @a == @b except permission bits, false otherwise.
+ */
 static bool tomoyo_same_path_acl(const struct tomoyo_acl_info *a,
 				 const struct tomoyo_acl_info *b)
 {
 	const struct tomoyo_path_acl *p1 = container_of(a, typeof(*p1), head);
 	const struct tomoyo_path_acl *p2 = container_of(b, typeof(*p2), head);
-	return tomoyo_same_acl_head(&p1->head, &p2->head) &&
-		tomoyo_same_name_union(&p1->name, &p2->name);
+	return tomoyo_same_name_union(&p1->name, &p2->name);
 }
 
 /**
@@ -364,23 +455,37 @@
 	return error;
 }
 
+/**
+ * tomoyo_same_mkdev_acl - Check for duplicated "struct tomoyo_mkdev_acl" entry.
+ *
+ * @a: Pointer to "struct tomoyo_acl_info".
+ * @b: Pointer to "struct tomoyo_acl_info".
+ *
+ * Returns true if @a == @b except permission bits, false otherwise.
+ */
 static bool tomoyo_same_mkdev_acl(const struct tomoyo_acl_info *a,
 					 const struct tomoyo_acl_info *b)
 {
-	const struct tomoyo_mkdev_acl *p1 = container_of(a, typeof(*p1),
-								head);
-	const struct tomoyo_mkdev_acl *p2 = container_of(b, typeof(*p2),
-								head);
-	return tomoyo_same_acl_head(&p1->head, &p2->head)
-		&& tomoyo_same_name_union(&p1->name, &p2->name)
-		&& tomoyo_same_number_union(&p1->mode, &p2->mode)
-		&& tomoyo_same_number_union(&p1->major, &p2->major)
-		&& tomoyo_same_number_union(&p1->minor, &p2->minor);
+	const struct tomoyo_mkdev_acl *p1 = container_of(a, typeof(*p1), head);
+	const struct tomoyo_mkdev_acl *p2 = container_of(b, typeof(*p2), head);
+	return tomoyo_same_name_union(&p1->name, &p2->name) &&
+		tomoyo_same_number_union(&p1->mode, &p2->mode) &&
+		tomoyo_same_number_union(&p1->major, &p2->major) &&
+		tomoyo_same_number_union(&p1->minor, &p2->minor);
 }
 
+/**
+ * tomoyo_merge_mkdev_acl - Merge duplicated "struct tomoyo_mkdev_acl" entry.
+ *
+ * @a:         Pointer to "struct tomoyo_acl_info".
+ * @b:         Pointer to "struct tomoyo_acl_info".
+ * @is_delete: True for @a &= ~@b, false for @a |= @b.
+ *
+ * Returns true if @a is empty, false otherwise.
+ */
 static bool tomoyo_merge_mkdev_acl(struct tomoyo_acl_info *a,
-					  struct tomoyo_acl_info *b,
-					  const bool is_delete)
+				   struct tomoyo_acl_info *b,
+				   const bool is_delete)
 {
 	u8 *const a_perm = &container_of(a, struct tomoyo_mkdev_acl,
 					 head)->perm;
@@ -411,9 +516,9 @@
  * Caller holds tomoyo_read_lock().
  */
 static int tomoyo_update_mkdev_acl(const u8 type, const char *filename,
-					  char *mode, char *major, char *minor,
-					  struct tomoyo_domain_info * const
-					  domain, const bool is_delete)
+				   char *mode, char *major, char *minor,
+				   struct tomoyo_domain_info * const domain,
+				   const bool is_delete)
 {
 	struct tomoyo_mkdev_acl e = {
 		.head.type = TOMOYO_TYPE_MKDEV_ACL,
@@ -436,16 +541,32 @@
 	return error;
 }
 
+/**
+ * tomoyo_same_path2_acl - Check for duplicated "struct tomoyo_path2_acl" entry.
+ *
+ * @a: Pointer to "struct tomoyo_acl_info".
+ * @b: Pointer to "struct tomoyo_acl_info".
+ *
+ * Returns true if @a == @b except permission bits, false otherwise.
+ */
 static bool tomoyo_same_path2_acl(const struct tomoyo_acl_info *a,
 				  const struct tomoyo_acl_info *b)
 {
 	const struct tomoyo_path2_acl *p1 = container_of(a, typeof(*p1), head);
 	const struct tomoyo_path2_acl *p2 = container_of(b, typeof(*p2), head);
-	return tomoyo_same_acl_head(&p1->head, &p2->head)
-		&& tomoyo_same_name_union(&p1->name1, &p2->name1)
-		&& tomoyo_same_name_union(&p1->name2, &p2->name2);
+	return tomoyo_same_name_union(&p1->name1, &p2->name1) &&
+		tomoyo_same_name_union(&p1->name2, &p2->name2);
 }
 
+/**
+ * tomoyo_merge_path2_acl - Merge duplicated "struct tomoyo_path2_acl" entry.
+ *
+ * @a:         Pointer to "struct tomoyo_acl_info".
+ * @b:         Pointer to "struct tomoyo_acl_info".
+ * @is_delete: True for @a &= ~@b, false for @a |= @b.
+ *
+ * Returns true if @a is empty, false otherwise.
+ */
 static bool tomoyo_merge_path2_acl(struct tomoyo_acl_info *a,
 				   struct tomoyo_acl_info *b,
 				   const bool is_delete)
@@ -532,6 +653,14 @@
 	return error;
 }
 
+/**
+ * tomoyo_same_path_number_acl - Check for duplicated "struct tomoyo_path_number_acl" entry.
+ *
+ * @a: Pointer to "struct tomoyo_acl_info".
+ * @b: Pointer to "struct tomoyo_acl_info".
+ *
+ * Returns true if @a == @b except permission bits, false otherwise.
+ */
 static bool tomoyo_same_path_number_acl(const struct tomoyo_acl_info *a,
 					const struct tomoyo_acl_info *b)
 {
@@ -539,11 +668,19 @@
 							       head);
 	const struct tomoyo_path_number_acl *p2 = container_of(b, typeof(*p2),
 							       head);
-	return tomoyo_same_acl_head(&p1->head, &p2->head)
-		&& tomoyo_same_name_union(&p1->name, &p2->name)
-		&& tomoyo_same_number_union(&p1->number, &p2->number);
+	return tomoyo_same_name_union(&p1->name, &p2->name) &&
+		tomoyo_same_number_union(&p1->number, &p2->number);
 }
 
+/**
+ * tomoyo_merge_path_number_acl - Merge duplicated "struct tomoyo_path_number_acl" entry.
+ *
+ * @a:         Pointer to "struct tomoyo_acl_info".
+ * @b:         Pointer to "struct tomoyo_acl_info".
+ * @is_delete: True for @a &= ~@b, false for @a |= @b.
+ *
+ * Returns true if @a is empty, false otherwise.
+ */
 static bool tomoyo_merge_path_number_acl(struct tomoyo_acl_info *a,
 					 struct tomoyo_acl_info *b,
 					 const bool is_delete)
@@ -575,8 +712,7 @@
 static int tomoyo_update_path_number_acl(const u8 type, const char *filename,
 					 char *number,
 					 struct tomoyo_domain_info * const
-					 domain,
-					 const bool is_delete)
+					 domain, const bool is_delete)
 {
 	struct tomoyo_path_number_acl e = {
 		.head.type = TOMOYO_TYPE_PATH_NUMBER_ACL,
@@ -737,7 +873,7 @@
  * Returns 0 on success, negative value otherwise.
  */
 int tomoyo_mkdev_perm(const u8 operation, struct path *path,
-			     const unsigned int mode, unsigned int dev)
+		      const unsigned int mode, unsigned int dev)
 {
 	struct tomoyo_request_info r;
 	int error = -ENOMEM;