configfs: remove old API

Remove the old show_attribute and store_attribute methods and update
the documentation.  Also replace the two C samples with a single new
one in the proper samples directory where people expect to find it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

fs/configfs/file.c

@@ -65,7 +65,6 @@ static int fill_read_buffer(struct dentry * dentry, struct configfs_buffer * buf
 {
 	struct configfs_attribute * attr = to_attr(dentry);
 	struct config_item * item = to_item(dentry->d_parent);
-	struct configfs_item_operations * ops = buffer->ops;
 	int ret = 0;
 	ssize_t count;
 
@@ -74,10 +73,7 @@ static int fill_read_buffer(struct dentry * dentry, struct configfs_buffer * buf
 	if (!buffer->page)
 		return -ENOMEM;
 
-	if (ops->show_attribute)
-		count = ops->show_attribute(item, attr, buffer->page);
-	else
-		count = attr->show(item, buffer->page);
+	count = attr->show(item, buffer->page);
 
 	buffer->needs_read_fill = 0;
 	BUG_ON(count > (ssize_t)SIMPLE_ATTR_SIZE);
@@ -175,10 +171,7 @@ flush_write_buffer(struct dentry * dentry, struct configfs_buffer * buffer, size
 {
 	struct configfs_attribute * attr = to_attr(dentry);
 	struct config_item * item = to_item(dentry->d_parent);
-	struct configfs_item_operations * ops = buffer->ops;
 
-	if (ops->store_attribute)
-		return ops->store_attribute(item, attr, buffer->page, count);
 	return attr->store(item, buffer->page, count);
 }
 
@@ -243,8 +236,7 @@ static int check_perm(struct inode * inode, struct file * file)
 	 * and we must have a store method.
 	 */
 	if (file->f_mode & FMODE_WRITE) {
-		if (!(inode->i_mode & S_IWUGO) ||
-		    (!ops->store_attribute && !attr->store))
+		if (!(inode->i_mode & S_IWUGO) || !attr->store)
 			goto Eaccess;
 
 	}
@@ -254,8 +246,7 @@ static int check_perm(struct inode * inode, struct file * file)
 	 * must be a show method for it.
 	 */
 	if (file->f_mode & FMODE_READ) {
-		if (!(inode->i_mode & S_IRUGO) ||
-		    (!ops->show_attribute && !attr->show))
+		if (!(inode->i_mode & S_IRUGO) || !attr->show)
 			goto Eaccess;
 	}