X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=include%2Flinux%2Fconfigfs.h;h=ddb7a97c78c25c1cf93a8302d79aa7f00d5e67a2;hb=f653398c86a1c104f0992bd788dd4bb065449be4;hp=4b287ad9371abe101956dd2a05015ca7cda7459f;hpb=0778361837bfaaa0bcf9ee79f0edd10e3a220899;p=safe%2Fjmp%2Flinux-2.6

diff --git a/include/linux/configfs.h b/include/linux/configfs.h
index 4b287ad..ddb7a97 100644
--- a/include/linux/configfs.h
+++ b/include/linux/configfs.h
@@ -27,21 +27,20 @@
  *
  * 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>
 
@@ -131,8 +130,25 @@ struct configfs_attribute {
 /*
  * 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. They can use
- * this macro (similar to sysfs' __ATTR) to make defining attributes easier.
+ * 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)			\
 {									\
@@ -144,13 +160,60 @@ struct configfs_attribute {
 	.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
@@ -194,6 +257,4 @@ void configfs_unregister_subsystem(struct configfs_subsystem *subsys);
 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  /* __KERNEL__ */
-
 #endif /* _CONFIGFS_H_ */