Merge "usb: u_ether: Add workqueue as bottom half handler for rx data path" into msm-3.4
diff --git a/drivers/usb/gadget/u_ether.c b/drivers/usb/gadget/u_ether.c
index 78ab8b7..fd10394 100644
--- a/drivers/usb/gadget/u_ether.c
+++ b/drivers/usb/gadget/u_ether.c
@@ -46,6 +46,8 @@
 
 #define UETH__VERSION	"29-May-2008"
 
+static struct workqueue_struct	*uether_wq;
+
 struct eth_dev {
 	/* lock is held while accessing port_usb
 	 * or updating its backlink port_usb->ioport
@@ -74,6 +76,7 @@
 						struct sk_buff_head *list);
 
 	struct work_struct	work;
+	struct work_struct	rx_work;
 
 	unsigned long		todo;
 #define	WORK_RX_MEMORY		0
@@ -88,7 +91,6 @@
 
 #define DEFAULT_QLEN	2	/* double buffering by default */
 
-
 #ifdef CONFIG_USB_GADGET_DUALSPEED
 
 static unsigned qmult = 10;
@@ -265,18 +267,16 @@
 		DBG(dev, "rx submit --> %d\n", retval);
 		if (skb)
 			dev_kfree_skb_any(skb);
-		spin_lock_irqsave(&dev->req_lock, flags);
-		list_add(&req->list, &dev->rx_reqs);
-		spin_unlock_irqrestore(&dev->req_lock, flags);
 	}
 	return retval;
 }
 
 static void rx_complete(struct usb_ep *ep, struct usb_request *req)
 {
-	struct sk_buff	*skb = req->context, *skb2;
+	struct sk_buff	*skb = req->context;
 	struct eth_dev	*dev = ep->driver_data;
 	int		status = req->status;
+	bool		queue = 0;
 
 	switch (status) {
 
@@ -300,30 +300,9 @@
 		} else {
 			skb_queue_tail(&dev->rx_frames, skb);
 		}
-		skb = NULL;
 
-		skb2 = skb_dequeue(&dev->rx_frames);
-		while (skb2) {
-			if (status < 0
-					|| ETH_HLEN > skb2->len
-					|| skb2->len > ETH_FRAME_LEN) {
-				dev->net->stats.rx_errors++;
-				dev->net->stats.rx_length_errors++;
-				DBG(dev, "rx length %d\n", skb2->len);
-				dev_kfree_skb_any(skb2);
-				goto next_frame;
-			}
-			skb2->protocol = eth_type_trans(skb2, dev->net);
-			dev->net->stats.rx_packets++;
-			dev->net->stats.rx_bytes += skb2->len;
-
-			/* no buffer copies needed, unless hardware can't
-			 * use skb buffers.
-			 */
-			status = netif_rx(skb2);
-next_frame:
-			skb2 = skb_dequeue(&dev->rx_frames);
-		}
+		if (!status)
+			queue = 1;
 		break;
 
 	/* software-driven interface shutdown */
@@ -346,22 +325,20 @@
 		/* FALLTHROUGH */
 
 	default:
+		queue = 1;
+		dev_kfree_skb_any(skb);
 		dev->net->stats.rx_errors++;
 		DBG(dev, "rx status %d\n", status);
 		break;
 	}
 
-	if (skb)
-		dev_kfree_skb_any(skb);
-	if (!netif_running(dev->net)) {
 clean:
-		spin_lock(&dev->req_lock);
-		list_add(&req->list, &dev->rx_reqs);
-		spin_unlock(&dev->req_lock);
-		req = NULL;
-	}
-	if (req)
-		rx_submit(dev, req, GFP_ATOMIC);
+	spin_lock(&dev->req_lock);
+	list_add(&req->list, &dev->rx_reqs);
+	spin_unlock(&dev->req_lock);
+
+	if (queue)
+		queue_work(uether_wq, &dev->rx_work);
 }
 
 static int prealloc(struct list_head *list, struct usb_ep *ep, unsigned n)
@@ -426,16 +403,24 @@
 {
 	struct usb_request	*req;
 	unsigned long		flags;
+	int			req_cnt = 0;
 
 	/* fill unused rxq slots with some skb */
 	spin_lock_irqsave(&dev->req_lock, flags);
 	while (!list_empty(&dev->rx_reqs)) {
+		/* break the nexus of continuous completion and re-submission*/
+		if (++req_cnt > qlen(dev->gadget))
+			break;
+
 		req = container_of(dev->rx_reqs.next,
 				struct usb_request, list);
 		list_del_init(&req->list);
 		spin_unlock_irqrestore(&dev->req_lock, flags);
 
 		if (rx_submit(dev, req, gfp_flags) < 0) {
+			spin_lock_irqsave(&dev->req_lock, flags);
+			list_add(&req->list, &dev->rx_reqs);
+			spin_unlock_irqrestore(&dev->req_lock, flags);
 			defer_kevent(dev, WORK_RX_MEMORY);
 			return;
 		}
@@ -445,6 +430,36 @@
 	spin_unlock_irqrestore(&dev->req_lock, flags);
 }
 
+static void process_rx_w(struct work_struct *work)
+{
+	struct eth_dev	*dev = container_of(work, struct eth_dev, rx_work);
+	struct sk_buff	*skb;
+	int		status = 0;
+
+	if (!dev->port_usb)
+		return;
+
+	while ((skb = skb_dequeue(&dev->rx_frames))) {
+		if (status < 0
+				|| ETH_HLEN > skb->len
+				|| skb->len > ETH_FRAME_LEN) {
+			dev->net->stats.rx_errors++;
+			dev->net->stats.rx_length_errors++;
+			DBG(dev, "rx length %d\n", skb->len);
+			dev_kfree_skb_any(skb);
+			continue;
+		}
+		skb->protocol = eth_type_trans(skb, dev->net);
+		dev->net->stats.rx_packets++;
+		dev->net->stats.rx_bytes += skb->len;
+
+		status = netif_rx_ni(skb);
+	}
+
+	if (netif_running(dev->net))
+		rx_fill(dev, GFP_KERNEL);
+}
+
 static void eth_work(struct work_struct *work)
 {
 	struct eth_dev	*dev = container_of(work, struct eth_dev, work);
@@ -931,6 +946,7 @@
 	spin_lock_init(&dev->lock);
 	spin_lock_init(&dev->req_lock);
 	INIT_WORK(&dev->work, eth_work);
+	INIT_WORK(&dev->rx_work, process_rx_w);
 	INIT_LIST_HEAD(&dev->tx_reqs);
 	INIT_LIST_HEAD(&dev->rx_reqs);
 
@@ -1096,6 +1112,7 @@
 {
 	struct eth_dev		*dev = link->ioport;
 	struct usb_request	*req;
+	struct sk_buff		*skb;
 
 	if (!dev)
 		return;
@@ -1138,6 +1155,12 @@
 		spin_lock(&dev->req_lock);
 	}
 	spin_unlock(&dev->req_lock);
+
+	spin_lock(&dev->rx_frames.lock);
+	while ((skb = __skb_dequeue(&dev->rx_frames)))
+		dev_kfree_skb_any(skb);
+	spin_unlock(&dev->rx_frames.lock);
+
 	link->out_ep->driver_data = NULL;
 	link->out_ep->desc = NULL;
 
@@ -1151,3 +1174,23 @@
 	link->ioport = NULL;
 	spin_unlock(&dev->lock);
 }
+
+static int __init gether_init(void)
+{
+	uether_wq  = create_singlethread_workqueue("uether");
+	if (!uether_wq) {
+		pr_err("%s: Unable to create workqueue: uether\n", __func__);
+		return -ENOMEM;
+	}
+	return 0;
+}
+module_init(gether_init);
+
+static void __exit gether_exit(void)
+{
+	destroy_workqueue(uether_wq);
+
+}
+module_exit(gether_exit);
+MODULE_DESCRIPTION("ethernet over USB driver");
+MODULE_LICENSE("GPL v2");