configfs: handle kzalloc() failure in check_perm()

check_perm() does not drop the reference to the module when kzalloc()
failure occurs.
Signed-Off-By: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>

fs/configfs/file.c

@@ -275,13 +275,14 @@ static int check_perm(struct inode * inode, struct file * file)
 	 * it in file->private_data for easy access.
 	 */
 	buffer = kzalloc(sizeof(struct configfs_buffer),GFP_KERNEL);
-	if (buffer) {
+	if (!buffer) {
+		error = -ENOMEM;
+		goto Enomem;
+	}
 	init_MUTEX(&buffer->sem);
 	buffer->needs_read_fill = 1;
 	buffer->ops = ops;
 	file->private_data = buffer;
-	} else
-		error = -ENOMEM;
 	goto Done;
 
  Einval:
@@ -289,6 +290,7 @@ static int check_perm(struct inode * inode, struct file * file)
 	goto Done;
  Eaccess:
 	error = -EACCES;
+ Enomem:
 	module_put(attr->ca_owner);
  Done:
 	if (error && item)