1 files changed, 270 insertions, 0 deletions
diff --git a/include/linux/configfs.h b/include/linux/configfs.h
new file mode 100644
index 000000000..2606711ad
--- /dev/null
+++ b/include/linux/configfs.h
@@ -0,0 +1,270 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * configfs.h - definitions for the device driver filesystem
+ *
+ * Based on sysfs:
+ * 	sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
+ *
+ * Based on kobject.h:
+ *      Copyright (c) 2002-2003	Patrick Mochel
+ *      Copyright (c) 2002-2003	Open Source Development Labs
+ *
+ * configfs Copyright (C) 2005 Oracle.  All rights reserved.
+ *
+ * Please read Documentation/filesystems/configfs.rst before using
+ * the configfs interface, ESPECIALLY the parts about reference counts and
+ * item destructors.
+ */
+
+#ifndef _CONFIGFS_H_
+#define _CONFIGFS_H_
+
+#include <linux/stat.h>   /* S_IRUGO */
+#include <linux/types.h>  /* ssize_t */
+#include <linux/list.h>   /* struct list_head */
+#include <linux/kref.h>   /* struct kref */
+#include <linux/mutex.h>  /* struct mutex */
+
+#define CONFIGFS_ITEM_NAME_LEN	20
+
+struct module;
+
+struct configfs_item_operations;
+struct configfs_group_operations;
+struct configfs_attribute;
+struct configfs_bin_attribute;
+struct configfs_subsystem;
+
+struct config_item {
+	char			*ci_name;
+	char			ci_namebuf[CONFIGFS_ITEM_NAME_LEN];
+	struct kref		ci_kref;
+	struct list_head	ci_entry;
+	struct config_item	*ci_parent;
+	struct config_group	*ci_group;
+	const struct config_item_type	*ci_type;
+	struct dentry		*ci_dentry;
+};
+
+extern __printf(2, 3)
+int config_item_set_name(struct config_item *, const char *, ...);
+
+static inline char *config_item_name(struct config_item * item)
+{
+	return item->ci_name;
+}
+
+extern void config_item_init_type_name(struct config_item *item,
+				       const char *name,
+				       const struct config_item_type *type);
+
+extern struct config_item *config_item_get(struct config_item *);
+extern struct config_item *config_item_get_unless_zero(struct config_item *);
+extern void config_item_put(struct config_item *);
+
+struct config_item_type {
+	struct module				*ct_owner;
+	struct configfs_item_operations		*ct_item_ops;
+	struct configfs_group_operations	*ct_group_ops;
+	struct configfs_attribute		**ct_attrs;
+	struct configfs_bin_attribute		**ct_bin_attrs;
+};
+
+/**
+ *	group - a group of config_items of a specific type, belonging
+ *	to a specific subsystem.
+ */
+struct config_group {
+	struct config_item		cg_item;
+	struct list_head		cg_children;
+	struct configfs_subsystem 	*cg_subsys;
+	struct list_head		default_groups;
+	struct list_head		group_entry;
+};
+
+extern void config_group_init(struct config_group *group);
+extern void config_group_init_type_name(struct config_group *group,
+					const char *name,
+					const struct config_item_type *type);
+
+static inline struct config_group *to_config_group(struct config_item *item)
+{
+	return item ? container_of(item,struct config_group,cg_item) : NULL;
+}
+
+static inline struct config_group *config_group_get(struct config_group *group)
+{
+	return group ? to_config_group(config_item_get(&group->cg_item)) : NULL;
+}
+
+static inline void config_group_put(struct config_group *group)
+{
+	config_item_put(&group->cg_item);
+}
+
+extern struct config_item *config_group_find_item(struct config_group *,
+						  const char *);
+
+
+static inline void configfs_add_default_group(struct config_group *new_group,
+		struct config_group *group)
+{
+	list_add_tail(&new_group->group_entry, &group->default_groups);
+}
+
+struct configfs_attribute {
+	const char		*ca_name;
+	struct module 		*ca_owner;
+	umode_t			ca_mode;
+	ssize_t (*show)(struct config_item *, char *);
+	ssize_t (*store)(struct config_item *, const char *, size_t);
+};
+
+#define CONFIGFS_ATTR(_pfx, _name)			\
+static struct configfs_attribute _pfx##attr_##_name = {	\
+	.ca_name	= __stringify(_name),		\
+	.ca_mode	= S_IRUGO | S_IWUSR,		\
+	.ca_owner	= THIS_MODULE,			\
+	.show		= _pfx##_name##_show,		\
+	.store		= _pfx##_name##_store,		\
+}
+
+#define CONFIGFS_ATTR_RO(_pfx, _name)			\
+static struct configfs_attribute _pfx##attr_##_name = {	\
+	.ca_name	= __stringify(_name),		\
+	.ca_mode	= S_IRUGO,			\
+	.ca_owner	= THIS_MODULE,			\
+	.show		= _pfx##_name##_show,		\
+}
+
+#define CONFIGFS_ATTR_WO(_pfx, _name)			\
+static struct configfs_attribute _pfx##attr_##_name = {	\
+	.ca_name	= __stringify(_name),		\
+	.ca_mode	= S_IWUSR,			\
+	.ca_owner	= THIS_MODULE,			\
+	.store		= _pfx##_name##_store,		\
+}
+
+struct file;
+struct vm_area_struct;
+
+struct configfs_bin_attribute {
+	struct configfs_attribute cb_attr;	/* std. attribute */
+	void *cb_private;			/* for user       */
+	size_t cb_max_size;			/* max core size  */
+	ssize_t (*read)(struct config_item *, void *, size_t);
+	ssize_t (*write)(struct config_item *, const void *, size_t);
+};
+
+#define CONFIGFS_BIN_ATTR(_pfx, _name, _priv, _maxsz)		\
+static struct configfs_bin_attribute _pfx##attr_##_name = {	\
+	.cb_attr = {						\
+		.ca_name	= __stringify(_name),		\
+		.ca_mode	= S_IRUGO | S_IWUSR,		\
+		.ca_owner	= THIS_MODULE,			\
+	},							\
+	.cb_private	= _priv,				\
+	.cb_max_size	= _maxsz,				\
+	.read		= _pfx##_name##_read,			\
+	.write		= _pfx##_name##_write,			\
+}
+
+#define CONFIGFS_BIN_ATTR_RO(_pfx, _name, _priv, _maxsz)	\
+static struct configfs_bin_attribute _pfx##attr_##_name = {	\
+	.cb_attr = {						\
+		.ca_name	= __stringify(_name),		\
+		.ca_mode	= S_IRUGO,			\
+		.ca_owner	= THIS_MODULE,			\
+	},							\
+	.cb_private	= _priv,				\
+	.cb_max_size	= _maxsz,				\
+	.read		= _pfx##_name##_read,			\
+}
+
+#define CONFIGFS_BIN_ATTR_WO(_pfx, _name, _priv, _maxsz)	\
+static struct configfs_bin_attribute _pfx##attr_##_name = {	\
+	.cb_attr = {						\
+		.ca_name	= __stringify(_name),		\
+		.ca_mode	= S_IWUSR,			\
+		.ca_owner	= THIS_MODULE,			\
+	},							\
+	.cb_private	= _priv,				\
+	.cb_max_size	= _maxsz,				\
+	.write		= _pfx##_name##_write,			\
+}
+
+/*
+ * If allow_link() exists, the item can symlink(2) out to other
+ * items.  If the item is a group, it may support mkdir(2).
+ * Groups supply one of make_group() and make_item().  If the
+ * group supports make_group(), one can create group children.  If it
+ * supports make_item(), one can create config_item children.  make_group()
+ * and make_item() return ERR_PTR() on errors.  If it has
+ * default_groups on group->default_groups, it has automatically created
+ * group children.  default_groups may coexist alongsize make_group() or
+ * make_item(), but if the group wishes to have only default_groups
+ * children (disallowing mkdir(2)), it need not provide either function.
+ */
+struct configfs_item_operations {
+	void (*release)(struct config_item *);
+	int (*allow_link)(struct config_item *src, struct config_item *target);
+	void (*drop_link)(struct config_item *src, struct config_item *target);
+};
+
+struct configfs_group_operations {
+	struct config_item *(*make_item)(struct config_group *group, const char *name);
+	struct config_group *(*make_group)(struct config_group *group, const char *name);
+	void (*disconnect_notify)(struct config_group *group, struct config_item *item);
+	void (*drop_item)(struct config_group *group, struct config_item *item);
+};
+
+struct configfs_subsystem {
+	struct config_group	su_group;
+	struct mutex		su_mutex;
+};
+
+static inline struct configfs_subsystem *to_configfs_subsystem(struct config_group *group)
+{
+	return group ?
+		container_of(group, struct configfs_subsystem, su_group) :
+		NULL;
+}
+
+int configfs_register_subsystem(struct configfs_subsystem *subsys);
+void configfs_unregister_subsystem(struct configfs_subsystem *subsys);
+
+int configfs_register_group(struct config_group *parent_group,
+			    struct config_group *group);
+void configfs_unregister_group(struct config_group *group);
+
+void configfs_remove_default_groups(struct config_group *group);
+
+struct config_group *
+configfs_register_default_group(struct config_group *parent_group,
+				const char *name,
+				const struct config_item_type *item_type);
+void configfs_unregister_default_group(struct config_group *group);
+
+/* These functions can sleep and can alloc with GFP_KERNEL */
+/* WARNING: These cannot be called underneath configfs callbacks!! */
+int configfs_depend_item(struct configfs_subsystem *subsys,
+			 struct config_item *target);
+void configfs_undepend_item(struct config_item *target);
+
+/*
+ * These functions can sleep and can alloc with GFP_KERNEL
+ * NOTE: These should be called only underneath configfs callbacks.
+ * NOTE: First parameter is a caller's subsystem, not target's.
+ * WARNING: These cannot be called on newly created item
+ *        (in make_group()/make_item() callback)
+ */
+int configfs_depend_item_unlocked(struct configfs_subsystem *caller_subsys,
+				  struct config_item *target);
+
+
+static inline void configfs_undepend_item_unlocked(struct config_item *target)
+{
+	configfs_undepend_item(target);
+}
+
+#endif /* _CONFIGFS_H_ */