string: factorize skip_spaces and export it to be generally available

[safe/jmp/linux-2.6] / include / linux / configfs.h

diff --git a/include/linux/configfs.h b/include/linux/configfs.h
index 8227e73..ddb7a97 100644 (file)
--- a/include/linux/configfs.h
+++ b/include/linux/configfs.h
@@ -27,20 +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>
 
@@ -130,8 +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)                   \
 {                                                                      \
@@ -143,13 +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
@@ -188,6 +252,9 @@ static inline struct configfs_subsystem *to_configfs_subsystem(struct config_gro
 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_ */