sysfs: marry api with struct kobject.

This works on obviating the need for a separate data type to describe a sysfs
directory (which was renamed from struct driver_dir_entry to struct sysfs_dir).

All sysfs creation and removal functions now take a struct kobject, instead
of a struct sysfs_dir. This kobject is embedded in ->d_fsdata of the directory.

sysfs_create_dir() takes only 1 parameter now: the object that we're creating
the directory for. The parent dentry is derived by looking at the object's 
parent. 

sysfs_create_file() takes the object as the first parameter, and the attribute
as the second, which makes more sense from an API perspective. 

sysfs_remove_file() now takes an attribute as a second parameter, to be 
consistent with the creation function.

sysfs_remove_link() is created, which is basically the old sysfs_remove_file().
(symlinks don't have an attribute associated with them; only a name, which was
prohibiting the previous change). 

open() and close() look for a kobject now, and do refcounting directly on the
object. Because of that, we don't need the ->open() and ->close() callbacks
in struct sysfs_ops, so they've been removed. 

read() and write() also now look for a kobject now. 

The comments have been updated, too. 

include/linux/kobject.h

@@ -16,6 +16,7 @@ struct kobject {
 	atomic_t		refcount;
 	struct list_head	entry;
 	struct kobject		* parent;
+	struct sysfs_dir	dir;
 };
 
 extern void kobject_init(struct kobject *);

include/linux/sysfs.h

@@ -11,18 +11,15 @@
 
 struct driver_dir_entry;
 struct attribute;
+struct kobject;
 
 struct sysfs_ops {
-	int	(*open)(struct driver_dir_entry *);
-	int	(*close)(struct driver_dir_entry *);
-	ssize_t	(*show)(struct driver_dir_entry *, struct attribute *,char *, size_t, loff_t);
-	ssize_t	(*store)(struct driver_dir_entry *,struct attribute *,const char *, size_t, loff_t);
+	ssize_t	(*show)(struct kobject *, struct attribute *,char *, size_t, loff_t);
+	ssize_t	(*store)(struct kobject *,struct attribute *,const char *, size_t, loff_t);
 };
 
-struct driver_dir_entry {
-	char			* name;
+struct sysfs_dir {
 	struct dentry		* dentry;
-	mode_t			mode;
 	struct sysfs_ops	* ops;
 };
 
@@ -32,20 +29,21 @@ struct attribute {
 };
 
 extern int
-sysfs_create_dir(struct driver_dir_entry *, struct driver_dir_entry *);
+sysfs_create_dir(struct kobject *);
 
 extern void
-sysfs_remove_dir(struct driver_dir_entry * entry);
+sysfs_remove_dir(struct kobject *);
 
 extern int
-sysfs_create_file(struct attribute * attr,
-		     struct driver_dir_entry * parent);
+sysfs_create_file(struct kobject *, struct attribute *);
+
+extern void
+sysfs_remove_file(struct kobject *, struct attribute *);
 
 extern int 
-sysfs_create_symlink(struct driver_dir_entry * parent, 
-			char * name, char * target);
+sysfs_create_link(struct kobject * kobj, char * name, char * target);
 
 extern void
-sysfs_remove_file(struct driver_dir_entry *, const char * name);
+sysfs_remove_link(struct kobject *, char * name);
 
 #endif /* _SYSFS_H_ */