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>

1 files changed, 43 insertions, 1 deletions

diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index af1fe4696509..7d471fca2743 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -233,6 +233,11 @@ void usbnet_skb_return (struct usbnet *dev, struct sk_buff *skb)
 {
         int     status;
 
+        if (test_bit(EVENT_RX_PAUSED, &dev->flags)) {
+                skb_queue_tail(&dev->rxq_pause, skb);
+                return;
+        }
+
         skb->protocol = eth_type_trans (skb, dev->net);
         dev->net->stats.rx_packets++;
         dev->net->stats.rx_bytes += skb->len;
@@ -526,6 +531,41 @@ static void intr_complete (struct urb *urb)
 }
 
 /*-------------------------------------------------------------------------*/
+void usbnet_pause_rx(struct usbnet *dev)
+{
+        set_bit(EVENT_RX_PAUSED, &dev->flags);
+
+        if (netif_msg_rx_status(dev))
+                devdbg(dev, "paused rx queue enabled");
+}
+EXPORT_SYMBOL_GPL(usbnet_pause_rx);
+
+void usbnet_resume_rx(struct usbnet *dev)
+{
+        struct sk_buff *skb;
+        int num = 0;
+
+        clear_bit(EVENT_RX_PAUSED, &dev->flags);
+
+        while ((skb = skb_dequeue(&dev->rxq_pause)) != NULL) {
+                usbnet_skb_return(dev, skb);
+                num++;
+        }
+
+        tasklet_schedule(&dev->bh);
+
+        if (netif_msg_rx_status(dev))
+                devdbg(dev, "paused rx queue disabled, %d skbs requeued", num);
+}
+EXPORT_SYMBOL_GPL(usbnet_resume_rx);
+
+void usbnet_purge_paused_rxq(struct usbnet *dev)
+{
+        skb_queue_purge(&dev->rxq_pause);
+}
+EXPORT_SYMBOL_GPL(usbnet_purge_paused_rxq);
+
+/*-------------------------------------------------------------------------*/
 
 // unlink pending rx/tx; completion handlers do all other cleanup
 
@@ -623,6 +663,8 @@ int usbnet_stop (struct net_device *net)
 
         usb_kill_urb(dev->interrupt);
 
+        usbnet_purge_paused_rxq(dev);
+
         /* deferred work (task, timer, softirq) must also stop.
          * can't flush_scheduled_work() until we drop rtnl (later),
          * else workers could deadlock; so make workers a NOP.
@@ -1113,7 +1155,6 @@ static void usbnet_bh (unsigned long param)
 }
 
 
-
 /*-------------------------------------------------------------------------
  *
  * USB Device Driver support
@@ -1210,6 +1251,7 @@ usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
         skb_queue_head_init (&dev->rxq);
         skb_queue_head_init (&dev->txq);
         skb_queue_head_init (&dev->done);
+        skb_queue_head_init(&dev->rxq_pause);
         dev->bh.func = usbnet_bh;
         dev->bh.data = (unsigned long) dev;
         INIT_WORK (&dev->kevent, kevent);