Staging: line6: only allocate a buffer if it is needed

Only allocate the version request buffer if it is needed, not when the
module starts up.  This will let us make the module_init path much
smaller.

CC: Markus Grabner <grabner@icg.tugraz.at>
CC: Stefan Hajnoczi <stefanha@gmail.com>
CC: Julia Lawall <julia@diku.dk>
CC: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/line6/driver.c

@@ -92,15 +92,10 @@ const unsigned char line6_midi_id[] = {
 	Code to request version of POD, Variax interface
 	(and maybe other devices).
 */
-static const char line6_request_version0[] = {
+static const char line6_request_version[] = {
 	0xf0, 0x7e, 0x7f, 0x06, 0x01, 0xf7
 };
 
-/*
-	Copy of version request code with GFP_KERNEL flag for use in URB.
-*/
-static const char *line6_request_version;
-
 struct usb_line6 *line6_devices[LINE6_MAX_DEVICES];
 
 /**
@@ -336,8 +331,21 @@ int line6_send_raw_message_async(struct usb_line6 *line6, const char *buffer,
 */
 int line6_version_request_async(struct usb_line6 *line6)
 {
-	return line6_send_raw_message_async(line6, line6_request_version,
-					    sizeof(line6_request_version0));
+	char *buffer;
+	int retval;
+
+	buffer = kmalloc(sizeof(line6_request_version), GFP_ATOMIC);
+	if (buffer == NULL) {
+		dev_err(line6->ifcdev, "Out of memory");
+		return -ENOMEM;
+	}
+
+	memcpy(buffer, line6_request_version, sizeof(line6_request_version));
+
+	retval = line6_send_raw_message_async(line6, buffer,
+					      sizeof(line6_request_version));
+	kfree(buffer);
+	return retval;
 }
 
 /*
@@ -1297,29 +1305,9 @@ static struct usb_driver line6_driver = {
 */
 static int __init line6_init(void)
 {
-	int retval;
-
 	printk(KERN_INFO "%s driver version %s\n", DRIVER_NAME, DRIVER_VERSION);
 
-	retval = usb_register(&line6_driver);
-
-	if (retval) {
-		err("usb_register failed. Error number %d", retval);
-		return retval;
-	}
-
-	line6_request_version = kmalloc(sizeof(line6_request_version0),
-					GFP_KERNEL);
-
-	if (line6_request_version == NULL) {
-		err("Out of memory");
-		return -ENOMEM;
-	}
-
-	memcpy((char *)line6_request_version, line6_request_version0,
-	       sizeof(line6_request_version0));
-
-	return retval;
+	return usb_register(&line6_driver);
 }
 
 /*
@@ -1347,7 +1335,6 @@ static void __exit line6_exit(void)
 	}
 
 	usb_deregister(&line6_driver);
-	kfree(line6_request_version);
 }
 
 module_init(line6_init);