[3.13.y-ckt stable] Patch "USB: serial: fix infinite wait_until_sent timeout" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    USB: serial: fix infinite wait_until_sent timeout

to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11-ckt19.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 4d140681c873030da05fb26565e1c2a5ec26839e Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan at kernel.org>
Date: Wed, 4 Mar 2015 10:39:05 +0100
Subject: USB: serial: fix infinite wait_until_sent timeout

commit f528bf4f57e43d1af4b2a5c97f09e43e0338c105 upstream.

Make sure to handle an infinite timeout (0).

Note that wait_until_sent is currently never called with a 0-timeout
argument due to a bug in tty_wait_until_sent.

Fixes: dcf010503966 ("USB: serial: add generic wait_until_sent
implementation")

Signed-off-by: Johan Hovold <johan at kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/usb/serial/generic.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index b63ce02..d6a1979 100644
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -258,7 +258,8 @@ void usb_serial_generic_wait_until_sent(struct tty_struct *tty, long timeout)
 	 * character or at least one jiffy.
 	 */
 	period = max_t(unsigned long, (10 * HZ / bps), 1);
-	period = min_t(unsigned long, period, timeout);
+	if (timeout)
+		period = min_t(unsigned long, period, timeout);

 	dev_dbg(&port->dev, "%s - timeout = %u ms, period = %u ms\n",
 					__func__, jiffies_to_msecs(timeout),
@@ -268,7 +269,7 @@ void usb_serial_generic_wait_until_sent(struct tty_struct *tty, long timeout)
 		schedule_timeout_interruptible(period);
 		if (signal_pending(current))
 			break;
-		if (time_after(jiffies, expire))
+		if (timeout && time_after(jiffies, expire))
 			break;
 	}
 }
--
1.9.1