USB: serial: fix infinite wait_until_sent timeout

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")
Cc: stable <stable@vger.kernel.org>	# v3.10

Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index ccf1df7c4b80..54e170dd3dad 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;
         }
 }