[PATCH 3.19 093/177] USB: serial: fix infinite wait_until_sent timeout

Greg Kroah-Hartman
2015-03-16T14:16:30Z

From: Johan Hovold <johan@kernel.org>

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

---
drivers/usb/serial/generic.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -258,7 +258,8 @@ void usb_serial_generic_wait_until_sent(
* 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(
schedule_timeout_interruptible(period);
if (signal_pending(current))
break;
- if (time_after(jiffies, expire))
+ if (timeout && time_after(jiffies, expire))
break;
}
}