*
* configfs Copyright (C) 2005 Oracle. All rights reserved.
*
- * Please read Documentation/filesystems/configfs.txt before using the
- * configfs interface, ESPECIALLY the parts about reference counts and
+ * Please read Documentation/filesystems/configfs/configfs.txt before using
+ * the configfs interface, ESPECIALLY the parts about reference counts and
* item destructors.
*/
#ifndef _CONFIGFS_H_
#define _CONFIGFS_H_
-#ifdef __KERNEL__
-
+#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/list.h>
#include <linux/kref.h>
+#include <linux/mutex.h>
+#include <linux/err.h>
#include <asm/atomic.h>
-#include <asm/semaphore.h>
#define CONFIGFS_ITEM_NAME_LEN 20
struct configfs_attribute **ct_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 config_group **default_groups;
};
-
extern void config_group_init(struct config_group *group);
extern void config_group_init_type_name(struct config_group *group,
const char *name,
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;
config_item_put(&group->cg_item);
}
-extern struct config_item *config_group_find_obj(struct config_group *, const char *);
+extern struct config_item *config_group_find_item(struct config_group *,
+ const char *);
struct configfs_attribute {
mode_t ca_mode;
};
+/*
+ * Users often need to create attribute structures for their configurable
+ * attributes, containing a configfs_attribute member and function pointers
+ * for the show() and store() operations on that attribute. If they don't
+ * need anything else on the extended attribute structure, they can use
+ * this macro to define it The argument _item is the name of the
+ * config_item structure.
+ */
+#define CONFIGFS_ATTR_STRUCT(_item) \
+struct _item##_attribute { \
+ struct configfs_attribute attr; \
+ ssize_t (*show)(struct _item *, char *); \
+ ssize_t (*store)(struct _item *, const char *, size_t); \
+}
+
+/*
+ * With the extended attribute structure, users can use this macro
+ * (similar to sysfs' __ATTR) to make defining attributes easier.
+ * An example:
+ * #define MYITEM_ATTR(_name, _mode, _show, _store) \
+ * struct myitem_attribute childless_attr_##_name = \
+ * __CONFIGFS_ATTR(_name, _mode, _show, _store)
+ */
+#define __CONFIGFS_ATTR(_name, _mode, _show, _store) \
+{ \
+ .attr = { \
+ .ca_name = __stringify(_name), \
+ .ca_mode = _mode, \
+ .ca_owner = THIS_MODULE, \
+ }, \
+ .show = _show, \
+ .store = _store, \
+}
+/* Here is a readonly version, only requiring a show() operation */
+#define __CONFIGFS_ATTR_RO(_name, _show) \
+{ \
+ .attr = { \
+ .ca_name = __stringify(_name), \
+ .ca_mode = 0444, \
+ .ca_owner = THIS_MODULE, \
+ }, \
+ .show = _show, \
+}
+
+/*
+ * With these extended attributes, the simple show_attribute() and
+ * store_attribute() operations need to call the show() and store() of the
+ * attributes. This is a common pattern, so we provide a macro to define
+ * them. The argument _item is the name of the config_item structure.
+ * This macro expects the attributes to be named "struct <name>_attribute"
+ * and the function to_<name>() to exist;
+ */
+#define CONFIGFS_ATTR_OPS(_item) \
+static ssize_t _item##_attr_show(struct config_item *item, \
+ struct configfs_attribute *attr, \
+ char *page) \
+{ \
+ struct _item *_item = to_##_item(item); \
+ struct _item##_attribute *_item##_attr = \
+ container_of(attr, struct _item##_attribute, attr); \
+ ssize_t ret = 0; \
+ \
+ if (_item##_attr->show) \
+ ret = _item##_attr->show(_item, page); \
+ return ret; \
+} \
+static ssize_t _item##_attr_store(struct config_item *item, \
+ struct configfs_attribute *attr, \
+ const char *page, size_t count) \
+{ \
+ struct _item *_item = to_##_item(item); \
+ struct _item##_attribute *_item##_attr = \
+ container_of(attr, struct _item##_attribute, attr); \
+ ssize_t ret = -EINVAL; \
+ \
+ if (_item##_attr->store) \
+ ret = _item##_attr->store(_item, page, count); \
+ return ret; \
+}
/*
* 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. If it has
+ * 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
struct config_item *(*make_item)(struct config_group *group, const char *name);
struct config_group *(*make_group)(struct config_group *group, const char *name);
int (*commit_item)(struct config_item *item);
+ 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 semaphore su_sem;
+ struct mutex su_mutex;
};
static inline struct configfs_subsystem *to_configfs_subsystem(struct config_group *group)
int configfs_register_subsystem(struct configfs_subsystem *subsys);
void configfs_unregister_subsystem(struct configfs_subsystem *subsys);
-#endif /* __KERNEL__ */
+/* 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 configfs_subsystem *subsys, struct config_item *target);
#endif /* _CONFIGFS_H_ */
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