USB: usb_wwan: fix urb leak in write error path

When enable usb serial for modem data, sometimes the tty is blocked
in tty_wait_until_sent because portdata->out_busy always is set and
have no chance to be cleared.

We find a bug in write error path. usb_wwan_write set portdata->out_busy
firstly, then try autopm async with error. No out urb submit and no
usb_wwan_outdat_callback to this write, portdata->out_busy can't be
cleared.

This patch clear portdata->out_busy if usb_wwan_write try autopm async
with error.

Fixes: 383cedc3bb43 ("USB: serial: full autosuspend support for the
option driver")

Signed-off-by: xiao jin <jin.xiao@intel.com>
Signed-off-by: Zhang, Qi1 <qi1.zhang@intel.com>
Reviewed-by: David Cohen <david.a.cohen@linux.intel.com>
Cc: <stable@vger.kernel.org>	# v2.6.32
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/usb/serial/usb_wwan.c b/drivers/usb/serial/usb_wwan.c
index b078440e822f..47ad7550c5a6 100644
--- a/drivers/usb/serial/usb_wwan.c
+++ b/drivers/usb/serial/usb_wwan.c
@@ -228,8 +228,10 @@ int usb_wwan_write(struct tty_struct *tty, struct usb_serial_port *port,
                         usb_pipeendpoint(this_urb->pipe), i);
 
                 err = usb_autopm_get_interface_async(port->serial->interface);
-                if (err < 0)
+                if (err < 0) {
+                        clear_bit(i, &portdata->out_busy);
                         break;
+                }
 
                 /* send the data */
                 memcpy(this_urb->transfer_buffer, buf, todo);