ipmi/watchdog: fix watchdog timeout set on reboot

BugLink: http://bugs.launchpad.net/bugs/1710646

commit 860f01e9 upstream.

systemd by default starts watchdog on reboot and sets the timer to
ShutdownWatchdogSec=10min.  Reboot handler in ipmi_watchdog than reduces
the timer to 120s which is not enough time to boot a Xen machine with
a lot of RAM.  As a result the machine is rebooted the second time
during the long run of (XEN) Scrubbing Free RAM.....

Fix this by setting the timer to 120s only if it was previously
set to a low value.
Signed-off-by: Valentin Vidic <Valentin.Vidic@CARNet.hr>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

drivers/char/ipmi/ipmi_watchdog.c

@@ -1162,10 +1162,11 @@ static int wdog_reboot_handler(struct notifier_block *this,
 			ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
 			ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
 		} else if (ipmi_watchdog_state != WDOG_TIMEOUT_NONE) {
-			/* Set a long timer to let the reboot happens, but
-			   reboot if it hangs, but only if the watchdog
+			/* Set a long timer to let the reboot happen or
+			   reset if it hangs, but only if the watchdog
 			   timer was already running. */
-			timeout = 120;
+			if (timeout < 120)
+				timeout = 120;
 			pretimeout = 0;
 			ipmi_watchdog_state = WDOG_TIMEOUT_RESET;
 			ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);