[PATCH 1/2] usb-serial : fix the nousb oops

[Dave Young <hidave.darkstar@gmail.com>]

In case with "nousb" booting, serial drivers will trigger kernel oops.

Here add usb_disabled() check in usb_serial_init and usb_serial_register

Signed-off-by: Dave Young <hidave.darkstar@gmail.com>
---
drivers/usb/serial/usb-serial.c |    6 ++++++
1 file changed, 6 insertions(+)

diff -uprN a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
--- a/drivers/usb/serial/usb-serial.c	2009-02-01 13:11:11.000000000 +0800
+++ b/drivers/usb/serial/usb-serial.c	2009-02-01 13:24:32.000000000 +0800
@@ -1113,6 +1113,9 @@ static int __init usb_serial_init(void)
 	int i;
 	int result;
 
+	if (usb_disabled())
+		return -ENODEV;
+
 	usb_serial_tty_driver = alloc_tty_driver(SERIAL_TTY_MINORS);
 	if (!usb_serial_tty_driver)
 		return -ENOMEM;
@@ -1230,6 +1233,9 @@ int usb_serial_register(struct usb_seria
 	/* must be called with BKL held */
 	int retval;
 
+	if (usb_disabled())
+		return -ENODEV;
+
 	fixup_generic(driver);
 
 	if (!driver->description)