bas_gigaset: fix pre_reset handling

The delayed work function int_in_work() may call usb_reset_device()
and thus, indirectly, the driver's pre_reset method. Trying to
cancel the work synchronously in that situation would deadlock.
Fix by avoiding cancel_work_sync() in the pre_reset method.

If the reset was NOT initiated by int_in_work() this might cause
int_in_work() to run after the post_reset method, with urb_int_in
already resubmitted, so handle that case gracefully.

Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/isdn/gigaset/bas-gigaset.c b/drivers/isdn/gigaset/bas-gigaset.c
index 5275887089483b6b8ff8ffdc1e9fad46ac1f81fb..c44950d3eb7b48f8a81fd16db9e46ecd15343a39 100644 (file)
--- a/drivers/isdn/gigaset/bas-gigaset.c
+++ b/drivers/isdn/gigaset/bas-gigaset.c
@@ -617,7 +617,13 @@ static void int_in_work(struct work_struct *work)
        if (rc == 0)
                /* success, resubmit interrupt read URB */
                rc = usb_submit_urb(urb, GFP_ATOMIC);
-       if (rc != 0 && rc != -ENODEV) {
+
+       switch (rc) {
+       case 0:         /* success */
+       case -ENODEV:   /* device gone */
+       case -EINVAL:   /* URB already resubmitted, or terminal badness */
+               break;
+       default:        /* failure: try to recover by resetting the device */
                dev_err(cs->dev, "clear halt failed: %s\n", get_usb_rcmsg(rc));
                rc = usb_lock_device_for_reset(ucs->udev, ucs->interface);
                if (rc == 0) {
@@ -2442,7 +2448,9 @@ static void gigaset_disconnect(struct usb_interface *interface)
 }
 
 /* gigaset_suspend
- * This function is called before the USB connection is suspended.
+ * This function is called before the USB connection is suspended
+ * or before the USB device is reset.
+ * In the latter case, message == PMSG_ON.
  */
 static int gigaset_suspend(struct usb_interface *intf, pm_message_t message)
 {
@@ -2498,7 +2506,12 @@ static int gigaset_suspend(struct usb_interface *intf, pm_message_t message)
        del_timer_sync(&ucs->timer_atrdy);
        del_timer_sync(&ucs->timer_cmd_in);
        del_timer_sync(&ucs->timer_int_in);
-       cancel_work_sync(&ucs->int_in_wq);
+
+       /* don't try to cancel int_in_wq from within reset as it
+        * might be the one requesting the reset
+        */
+       if (message.event != PM_EVENT_ON)
+               cancel_work_sync(&ucs->int_in_wq);
 
        gig_dbg(DEBUG_SUSPEND, "suspend complete");
        return 0;