usbnet: add rx queue pausing

Add rx queue pausing to usbnet. This is needed by rndis_wlan so that it can
control rx queue and prevent received packets from being send forward before
rndis_wlan receives and handles 'media connect'-indication. Without this
establishing WPA connections is hard and fail often.

[v2] - removed unneeded use of skb_clone

Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/rndis_wlan.c b/drivers/net/wireless/rndis_wlan.c
index 828dc18..d42692d 100644
--- a/drivers/net/wireless/rndis_wlan.c
+++ b/drivers/net/wireless/rndis_wlan.c
@@ -1764,8 +1764,15 @@
 
 	if (!wrqu->essid.flags || length == 0)
 		return disassociate(usbdev, 1);
-	else
+	else {
+		/* Pause and purge rx queue, so we don't pass packets before
+		 * 'media connect'-indication.
+		 */
+		usbnet_pause_rx(usbdev);
+		usbnet_purge_paused_rxq(usbdev);
+
 		return set_essid(usbdev, &ssid);
+	}
 }
 
 
@@ -2328,6 +2335,8 @@
 			memcpy(evt.ap_addr.sa_data, bssid, ETH_ALEN);
 			wireless_send_event(usbdev->net, SIOCGIWAP, &evt, NULL);
 		}
+
+		usbnet_resume_rx(usbdev);
 	}
 
 	if (test_and_clear_bit(WORK_LINK_DOWN, &priv->work_pending)) {
@@ -2541,6 +2550,8 @@
 
 	switch (msg->status) {
 	case RNDIS_STATUS_MEDIA_CONNECT:
+		usbnet_pause_rx(usbdev);
+
 		devinfo(usbdev, "media connect");
 
 		/* queue work to avoid recursive calls into rndis_command */