5 files changed, 72 insertions, 81 deletions

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 4a16d6e33c09..1545cbee77a4 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -48,7 +48,6 @@
 #include <linux/debugfs.h>
 
 typedef unsigned int pending_ring_idx_t;
-#define INVALID_PENDING_RING_IDX (~0U)
 
 struct pending_tx_info {
 	struct xen_netif_tx_request req; /* tx request */
@@ -63,7 +62,7 @@ struct pending_tx_info {
 	 * ubuf_to_vif is a helper which finds the struct xenvif from a pointer
 	 * to this field.
 	 */
-	struct ubuf_info callback_struct;
+	struct ubuf_info_msgzc callback_struct;
 };
 
 #define XEN_NETIF_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, XEN_PAGE_SIZE)
@@ -82,8 +81,6 @@ struct xenvif_rx_meta {
 /* Discriminate from any valid pending_idx value. */
 #define INVALID_PENDING_IDX 0xFFFF
 
-#define MAX_BUFFER_OFFSET XEN_PAGE_SIZE
-
 #define MAX_PENDING_REQS XEN_NETIF_TX_RING_SIZE
 
 /* The maximum number of frags is derived from the size of a grant (same
@@ -203,6 +200,7 @@ struct xenvif_queue { /* Per-queue data for xenvif */
 	unsigned int rx_queue_max;
 	unsigned int rx_queue_len;
 	unsigned long last_rx_time;
+	unsigned int rx_slots_needed;
 	bool stalled;
 
 	struct xenvif_copy_state rx_copy;
@@ -366,11 +364,6 @@ void xenvif_free(struct xenvif *vif);
 int xenvif_xenbus_init(void);
 void xenvif_xenbus_fini(void);
 
-int xenvif_schedulable(struct xenvif *vif);
-
-int xenvif_queue_stopped(struct xenvif_queue *queue);
-void xenvif_wake_queue(struct xenvif_queue *queue);
-
 /* (Un)Map communication rings. */
 void xenvif_unmap_frontend_data_rings(struct xenvif_queue *queue);
 int xenvif_map_frontend_data_rings(struct xenvif_queue *queue,
@@ -393,7 +386,6 @@ int xenvif_dealloc_kthread(void *data);
 irqreturn_t xenvif_ctrl_irq_fn(int irq, void *data);
 
 bool xenvif_have_rx_work(struct xenvif_queue *queue, bool test_kthread);
-void xenvif_rx_action(struct xenvif_queue *queue);
 void xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb);
 
 void xenvif_carrier_on(struct xenvif *vif);
@@ -402,9 +394,6 @@ void xenvif_carrier_on(struct xenvif *vif);
 void xenvif_zerocopy_callback(struct sk_buff *skb, struct ubuf_info *ubuf,
 			      bool zerocopy_success);
 
-/* Unmap a pending page and release it back to the guest */
-void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx);
-
 static inline pending_ring_idx_t nr_pending_reqs(struct xenvif_queue *queue)
 {
 	return MAX_PENDING_REQS -
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index fe8e21ad8ed9..650fa180220f 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -42,7 +42,6 @@
 #include <xen/balloon.h>
 
 #define XENVIF_QUEUE_LENGTH 32
-#define XENVIF_NAPI_WEIGHT  64
 
 /* Number of bytes allowed on the internal guest Rx queue. */
 #define XENVIF_RX_QUEUE_BYTES (XEN_NETIF_RX_RING_SIZE/2 * PAGE_SIZE)
@@ -70,7 +69,7 @@ void xenvif_skb_zerocopy_complete(struct xenvif_queue *queue)
 	wake_up(&queue->dealloc_wq);
 }
 
-int xenvif_schedulable(struct xenvif *vif)
+static int xenvif_schedulable(struct xenvif *vif)
 {
 	return netif_running(vif->dev) &&
 		test_bit(VIF_STATUS_CONNECTED, &vif->status) &&
@@ -178,20 +177,6 @@ irqreturn_t xenvif_interrupt(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
-int xenvif_queue_stopped(struct xenvif_queue *queue)
-{
-	struct net_device *dev = queue->vif->dev;
-	unsigned int id = queue->id;
-	return netif_tx_queue_stopped(netdev_get_tx_queue(dev, id));
-}
-
-void xenvif_wake_queue(struct xenvif_queue *queue)
-{
-	struct net_device *dev = queue->vif->dev;
-	unsigned int id = queue->id;
-	netif_tx_wake_queue(netdev_get_tx_queue(dev, id));
-}
-
 static u16 xenvif_select_queue(struct net_device *dev, struct sk_buff *skb,
 			       struct net_device *sb_dev)
 {
@@ -606,8 +591,8 @@ int xenvif_init_queue(struct xenvif_queue *queue)
 	}
 
 	for (i = 0; i < MAX_PENDING_REQS; i++) {
-		queue->pending_tx_info[i].callback_struct = (struct ubuf_info)
-			{ .callback = xenvif_zerocopy_callback,
+		queue->pending_tx_info[i].callback_struct = (struct ubuf_info_msgzc)
+			{ { .callback = xenvif_zerocopy_callback },
 			  { { .ctx = NULL,
 			      .desc = i } } };
 		queue->grant_tx_handle[i] = NETBACK_INVALID_HANDLE;
@@ -738,8 +723,7 @@ int xenvif_connect_data(struct xenvif_queue *queue,
 	init_waitqueue_head(&queue->dealloc_wq);
 	atomic_set(&queue->inflight_packets, 0);
 
-	netif_napi_add(queue->vif->dev, &queue->napi, xenvif_poll,
-			XENVIF_NAPI_WEIGHT);
+	netif_napi_add(queue->vif->dev, &queue->napi, xenvif_poll);
 
 	queue->stalled = true;
 
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 0f7fd159f0f2..3d2081bbbc86 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -112,6 +112,8 @@ static void make_tx_response(struct xenvif_queue *queue,
 			     s8       st);
 static void push_tx_responses(struct xenvif_queue *queue);
 
+static void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx);
+
 static inline int tx_work_todo(struct xenvif_queue *queue);
 
 static inline unsigned long idx_to_pfn(struct xenvif_queue *queue,
@@ -131,7 +133,7 @@ static inline unsigned long idx_to_kaddr(struct xenvif_queue *queue,
 
 /* Find the containing VIF's structure from a pointer in pending_tx_info array
  */
-static inline struct xenvif_queue *ubuf_to_queue(const struct ubuf_info *ubuf)
+static inline struct xenvif_queue *ubuf_to_queue(const struct ubuf_info_msgzc *ubuf)
 {
 	u16 pending_idx = ubuf->desc;
 	struct pending_tx_info *temp =
@@ -828,7 +830,7 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
 			break;
 		}
 
-		work_to_do = RING_HAS_UNCONSUMED_REQUESTS(&queue->tx);
+		work_to_do = XEN_RING_NR_UNCONSUMED_REQUESTS(&queue->tx);
 		if (!work_to_do)
 			break;
 
@@ -1199,9 +1201,7 @@ static int xenvif_tx_submit(struct xenvif_queue *queue)
 			}
 
 			mss = skb_shinfo(skb)->gso_size;
-			hdrlen = skb_transport_header(skb) -
-				skb_mac_header(skb) +
-				tcp_hdrlen(skb);
+			hdrlen = skb_tcp_all_headers(skb);
 
 			skb_shinfo(skb)->gso_segs =
 				DIV_ROUND_UP(skb->len - hdrlen, mss);
@@ -1228,11 +1228,12 @@ static int xenvif_tx_submit(struct xenvif_queue *queue)
 	return work_done;
 }
 
-void xenvif_zerocopy_callback(struct sk_buff *skb, struct ubuf_info *ubuf,
+void xenvif_zerocopy_callback(struct sk_buff *skb, struct ubuf_info *ubuf_base,
 			      bool zerocopy_success)
 {
 	unsigned long flags;
 	pending_ring_idx_t index;
+	struct ubuf_info_msgzc *ubuf = uarg_to_msgzc(ubuf_base);
 	struct xenvif_queue *queue = ubuf_to_queue(ubuf);
 
 	/* This is the only place where we grab this lock, to protect callbacks
@@ -1241,7 +1242,7 @@ void xenvif_zerocopy_callback(struct sk_buff *skb, struct ubuf_info *ubuf,
 	spin_lock_irqsave(&queue->callback_lock, flags);
 	do {
 		u16 pending_idx = ubuf->desc;
-		ubuf = (struct ubuf_info *) ubuf->ctx;
+		ubuf = (struct ubuf_info_msgzc *) ubuf->ctx;
 		BUG_ON(queue->dealloc_prod - queue->dealloc_cons >=
 			MAX_PENDING_REQS);
 		index = pending_index(queue->dealloc_prod);
@@ -1418,7 +1419,7 @@ static void push_tx_responses(struct xenvif_queue *queue)
 		notify_remote_via_irq(queue->tx_irq);
 }
 
-void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx)
+static void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx)
 {
 	int ret;
 	struct gnttab_unmap_grant_ref tx_unmap_op;
diff --git a/drivers/net/xen-netback/rx.c b/drivers/net/xen-netback/rx.c
index accc991d153f..932762177110 100644
--- a/drivers/net/xen-netback/rx.c
+++ b/drivers/net/xen-netback/rx.c
@@ -33,28 +33,36 @@
 #include <xen/xen.h>
 #include <xen/events.h>
 
-static bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue)
+/*
+ * Update the needed ring page slots for the first SKB queued.
+ * Note that any call sequence outside the RX thread calling this function
+ * needs to wake up the RX thread via a call of xenvif_kick_thread()
+ * afterwards in order to avoid a race with putting the thread to sleep.
+ */
+static void xenvif_update_needed_slots(struct xenvif_queue *queue,
+				       const struct sk_buff *skb)
 {
-	RING_IDX prod, cons;
-	struct sk_buff *skb;
-	int needed;
-	unsigned long flags;
-
-	spin_lock_irqsave(&queue->rx_queue.lock, flags);
+	unsigned int needed = 0;
 
-	skb = skb_peek(&queue->rx_queue);
-	if (!skb) {
-		spin_unlock_irqrestore(&queue->rx_queue.lock, flags);
-		return false;
+	if (skb) {
+		needed = DIV_ROUND_UP(skb->len, XEN_PAGE_SIZE);
+		if (skb_is_gso(skb))
+			needed++;
+		if (skb->sw_hash)
+			needed++;
 	}
 
-	needed = DIV_ROUND_UP(skb->len, XEN_PAGE_SIZE);
-	if (skb_is_gso(skb))
-		needed++;
-	if (skb->sw_hash)
-		needed++;
+	WRITE_ONCE(queue->rx_slots_needed, needed);
+}
 
-	spin_unlock_irqrestore(&queue->rx_queue.lock, flags);
+static bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue)
+{
+	RING_IDX prod, cons;
+	unsigned int needed;
+
+	needed = READ_ONCE(queue->rx_slots_needed);
+	if (!needed)
+		return false;
 
 	do {
 		prod = queue->rx.sring->req_prod;
@@ -80,13 +88,19 @@ void xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb)
 
 	spin_lock_irqsave(&queue->rx_queue.lock, flags);
 
-	__skb_queue_tail(&queue->rx_queue, skb);
-
-	queue->rx_queue_len += skb->len;
-	if (queue->rx_queue_len > queue->rx_queue_max) {
+	if (queue->rx_queue_len >= queue->rx_queue_max) {
 		struct net_device *dev = queue->vif->dev;
 
 		netif_tx_stop_queue(netdev_get_tx_queue(dev, queue->id));
+		kfree_skb(skb);
+		queue->vif->dev->stats.rx_dropped++;
+	} else {
+		if (skb_queue_empty(&queue->rx_queue))
+			xenvif_update_needed_slots(queue, skb);
+
+		__skb_queue_tail(&queue->rx_queue, skb);
+
+		queue->rx_queue_len += skb->len;
 	}
 
 	spin_unlock_irqrestore(&queue->rx_queue.lock, flags);
@@ -100,6 +114,8 @@ static struct sk_buff *xenvif_rx_dequeue(struct xenvif_queue *queue)
 
 	skb = __skb_dequeue(&queue->rx_queue);
 	if (skb) {
+		xenvif_update_needed_slots(queue, skb_peek(&queue->rx_queue));
+
 		queue->rx_queue_len -= skb->len;
 		if (queue->rx_queue_len < queue->rx_queue_max) {
 			struct netdev_queue *txq;
@@ -134,6 +150,7 @@ static void xenvif_rx_queue_drop_expired(struct xenvif_queue *queue)
 			break;
 		xenvif_rx_dequeue(queue);
 		kfree_skb(skb);
+		queue->vif->dev->stats.rx_dropped++;
 	}
 }
 
@@ -469,7 +486,7 @@ static void xenvif_rx_skb(struct xenvif_queue *queue)
 
 #define RX_BATCH_SIZE 64
 
-void xenvif_rx_action(struct xenvif_queue *queue)
+static void xenvif_rx_action(struct xenvif_queue *queue)
 {
 	struct sk_buff_head completed_skbs;
 	unsigned int work_done = 0;
@@ -478,6 +495,7 @@ void xenvif_rx_action(struct xenvif_queue *queue)
 	queue->rx_copy.completed = &completed_skbs;
 
 	while (xenvif_rx_ring_slots_available(queue) &&
+	       !skb_queue_empty(&queue->rx_queue) &&
 	       work_done < RX_BATCH_SIZE) {
 		xenvif_rx_skb(queue);
 		work_done++;
@@ -487,27 +505,31 @@ void xenvif_rx_action(struct xenvif_queue *queue)
 	xenvif_rx_copy_flush(queue);
 }
 
-static bool xenvif_rx_queue_stalled(struct xenvif_queue *queue)
+static RING_IDX xenvif_rx_queue_slots(const struct xenvif_queue *queue)
 {
 	RING_IDX prod, cons;
 
 	prod = queue->rx.sring->req_prod;
 	cons = queue->rx.req_cons;
 
+	return prod - cons;
+}
+
+static bool xenvif_rx_queue_stalled(const struct xenvif_queue *queue)
+{
+	unsigned int needed = READ_ONCE(queue->rx_slots_needed);
+
 	return !queue->stalled &&
-		prod - cons < 1 &&
+		xenvif_rx_queue_slots(queue) < needed &&
 		time_after(jiffies,
 			   queue->last_rx_time + queue->vif->stall_timeout);
 }
 
 static bool xenvif_rx_queue_ready(struct xenvif_queue *queue)
 {
-	RING_IDX prod, cons;
-
-	prod = queue->rx.sring->req_prod;
-	cons = queue->rx.req_cons;
+	unsigned int needed = READ_ONCE(queue->rx_slots_needed);
 
-	return queue->stalled && prod - cons >= 1;
+	return queue->stalled && xenvif_rx_queue_slots(queue) >= needed;
 }
 
 bool xenvif_have_rx_work(struct xenvif_queue *queue, bool test_kthread)
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index d24b7a7993aa..c1ba4294f364 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -675,7 +675,6 @@ static void hotplug_status_changed(struct xenbus_watch *watch,
 
 		/* Not interested in this watch anymore. */
 		unregister_hotplug_status_watch(be);
-		xenbus_rm(XBT_NIL, be->dev->nodename, "hotplug-status");
 	}
 	kfree(str);
 }
@@ -824,15 +823,11 @@ static void connect(struct backend_info *be)
 	xenvif_carrier_on(be->vif);
 
 	unregister_hotplug_status_watch(be);
-	if (xenbus_exists(XBT_NIL, dev->nodename, "hotplug-status")) {
-		err = xenbus_watch_pathfmt(dev, &be->hotplug_status_watch,
-					   NULL, hotplug_status_changed,
-					   "%s/%s", dev->nodename,
-					   "hotplug-status");
-		if (err)
-			goto err;
+	err = xenbus_watch_pathfmt(dev, &be->hotplug_status_watch, NULL,
+				   hotplug_status_changed,
+				   "%s/%s", dev->nodename, "hotplug-status");
+	if (!err)
 		be->have_hotplug_status_watch = 1;
-	}
 
 	netif_tx_wake_all_queues(be->vif->dev);
 
@@ -870,13 +865,12 @@ static int connect_data_rings(struct backend_info *be,
 	 * queue-N.
 	 */
 	if (num_queues == 1) {
-		xspath = kzalloc(strlen(dev->otherend) + 1, GFP_KERNEL);
+		xspath = kstrdup(dev->otherend, GFP_KERNEL);
 		if (!xspath) {
 			xenbus_dev_fatal(dev, -ENOMEM,
 					 "reading ring references");
 			return -ENOMEM;
 		}
-		strcpy(xspath, dev->otherend);
 	} else {
 		xspathsize = strlen(dev->otherend) + xenstore_path_ext_size;
 		xspath = kzalloc(xspathsize, GFP_KERNEL);
@@ -988,6 +982,7 @@ static int netback_remove(struct xenbus_device *dev)
 	struct backend_info *be = dev_get_drvdata(&dev->dev);
 
 	unregister_hotplug_status_watch(be);
+	xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status");
 	if (be->vif) {
 		kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE);
 		backend_disconnect(be);