xen-netback: Factor queue-specific data into queue struct

In preparation for multi-queue support in xen-netback, move the
queue-specific data from struct xenvif into struct xenvif_queue, and
update the rest of the code to use this.

Also adds loops over queues where appropriate, even though only one is
configured at this point, and uses alloc_netdev_mq() and the
corresponding multi-queue netif wake/start/stop functions in preparation
for multiple active queues.

Finally, implements a trivial queue selection function suitable for
ndo_select_queue, which simply returns 0 for a single queue and uses
skb_get_hash() to compute the queue index otherwise.

Signed-off-by: Andrew J. Bennieston <andrew.bennieston@citrix.com>
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 819 insertions, 590 deletions

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 2c283d693330..b6885cfcc7df 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -99,22 +99,43 @@ struct xenvif_rx_meta {
  */
 #define XEN_NETBK_LEGACY_SLOTS_MAX XEN_NETIF_NR_SLOTS_MIN
 
-struct xenvif {
-	/* Unique identifier for this interface. */
-	domid_t          domid;
-	unsigned int     handle;
+/* Queue name is interface name with "-qNNN" appended */
+#define QUEUE_NAME_SIZE (IFNAMSIZ + 5)
 
-	/* Is this interface disabled? True when backend discovers
-	 * frontend is rogue.
+/* IRQ name is queue name with "-tx" or "-rx" appended */
+#define IRQ_NAME_SIZE (QUEUE_NAME_SIZE + 3)
+
+struct xenvif;
+
+struct xenvif_stats {
+	/* Stats fields to be updated per-queue.
+	 * A subset of struct net_device_stats that contains only the
+	 * fields that are updated in netback.c for each queue.
 	 */
-	bool disabled;
+	unsigned int rx_bytes;
+	unsigned int rx_packets;
+	unsigned int tx_bytes;
+	unsigned int tx_packets;
+
+	/* Additional stats used by xenvif */
+	unsigned long rx_gso_checksum_fixup;
+	unsigned long tx_zerocopy_sent;
+	unsigned long tx_zerocopy_success;
+	unsigned long tx_zerocopy_fail;
+	unsigned long tx_frag_overflow;
+};
+
+struct xenvif_queue { /* Per-queue data for xenvif */
+	unsigned int id; /* Queue ID, 0-based */
+	char name[QUEUE_NAME_SIZE]; /* DEVNAME-qN */
+	struct xenvif *vif; /* Parent VIF */
 
 	/* Use NAPI for guest TX */
 	struct napi_struct napi;
 	/* When feature-split-event-channels = 0, tx_irq = rx_irq. */
 	unsigned int tx_irq;
 	/* Only used when feature-split-event-channels = 1 */
-	char tx_irq_name[IFNAMSIZ+4]; /* DEVNAME-tx */
+	char tx_irq_name[IRQ_NAME_SIZE]; /* DEVNAME-qN-tx */
 	struct xen_netif_tx_back_ring tx;
 	struct sk_buff_head tx_queue;
 	struct page *mmap_pages[MAX_PENDING_REQS];
@@ -150,7 +171,7 @@ struct xenvif {
 	/* When feature-split-event-channels = 0, tx_irq = rx_irq. */
 	unsigned int rx_irq;
 	/* Only used when feature-split-event-channels = 1 */
-	char rx_irq_name[IFNAMSIZ+4]; /* DEVNAME-rx */
+	char rx_irq_name[IRQ_NAME_SIZE]; /* DEVNAME-qN-rx */
 	struct xen_netif_rx_back_ring rx;
 	struct sk_buff_head rx_queue;
 	RING_IDX rx_last_skb_slots;
@@ -165,6 +186,22 @@ struct xenvif {
 	 */
 	struct xenvif_rx_meta meta[XEN_NETIF_RX_RING_SIZE];
 
+	/* Transmit shaping: allow 'credit_bytes' every 'credit_usec'. */
+	unsigned long   credit_bytes;
+	unsigned long   credit_usec;
+	unsigned long   remaining_credit;
+	struct timer_list credit_timeout;
+	u64 credit_window_start;
+
+	/* Statistics */
+	struct xenvif_stats stats;
+};
+
+struct xenvif {
+	/* Unique identifier for this interface. */
+	domid_t          domid;
+	unsigned int     handle;
+
 	u8               fe_dev_addr[6];
 
 	/* Frontend feature information. */
@@ -178,19 +215,13 @@ struct xenvif {
 	/* Internal feature information. */
 	u8 can_queue:1;	    /* can queue packets for receiver? */
 
-	/* Transmit shaping: allow 'credit_bytes' every 'credit_usec'. */
-	unsigned long   credit_bytes;
-	unsigned long   credit_usec;
-	unsigned long   remaining_credit;
-	struct timer_list credit_timeout;
-	u64 credit_window_start;
+	/* Is this interface disabled? True when backend discovers
+	 * frontend is rogue.
+	 */
+	bool disabled;
 
-	/* Statistics */
-	unsigned long rx_gso_checksum_fixup;
-	unsigned long tx_zerocopy_sent;
-	unsigned long tx_zerocopy_success;
-	unsigned long tx_zerocopy_fail;
-	unsigned long tx_frag_overflow;
+	/* Queues */
+	struct xenvif_queue *queues;
 
 	/* Miscellaneous private stuff. */
 	struct net_device *dev;
@@ -205,7 +236,9 @@ struct xenvif *xenvif_alloc(struct device *parent,
 			    domid_t domid,
 			    unsigned int handle);
 
-int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
+int xenvif_init_queue(struct xenvif_queue *queue);
+
+int xenvif_connect(struct xenvif_queue *queue, unsigned long tx_ring_ref,
 		   unsigned long rx_ring_ref, unsigned int tx_evtchn,
 		   unsigned int rx_evtchn);
 void xenvif_disconnect(struct xenvif *vif);
@@ -216,44 +249,47 @@ void xenvif_xenbus_fini(void);
 
 int xenvif_schedulable(struct xenvif *vif);
 
-int xenvif_must_stop_queue(struct xenvif *vif);
+int xenvif_must_stop_queue(struct xenvif_queue *queue);
+
+int xenvif_queue_stopped(struct xenvif_queue *queue);
+void xenvif_wake_queue(struct xenvif_queue *queue);
 
 /* (Un)Map communication rings. */
-void xenvif_unmap_frontend_rings(struct xenvif *vif);
-int xenvif_map_frontend_rings(struct xenvif *vif,
+void xenvif_unmap_frontend_rings(struct xenvif_queue *queue);
+int xenvif_map_frontend_rings(struct xenvif_queue *queue,
 			      grant_ref_t tx_ring_ref,
 			      grant_ref_t rx_ring_ref);
 
 /* Check for SKBs from frontend and schedule backend processing */
-void xenvif_napi_schedule_or_enable_events(struct xenvif *vif);
+void xenvif_napi_schedule_or_enable_events(struct xenvif_queue *queue);
 
 /* Prevent the device from generating any further traffic. */
 void xenvif_carrier_off(struct xenvif *vif);
 
-int xenvif_tx_action(struct xenvif *vif, int budget);
+int xenvif_tx_action(struct xenvif_queue *queue, int budget);
 
 int xenvif_kthread_guest_rx(void *data);
-void xenvif_kick_thread(struct xenvif *vif);
+void xenvif_kick_thread(struct xenvif_queue *queue);
 
 int xenvif_dealloc_kthread(void *data);
 
 /* Determine whether the needed number of slots (req) are available,
  * and set req_event if not.
  */
-bool xenvif_rx_ring_slots_available(struct xenvif *vif, int needed);
+bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue, int needed);
 
-void xenvif_stop_queue(struct xenvif *vif);
+void xenvif_carrier_on(struct xenvif *vif);
 
 /* Callback from stack when TX packet can be released */
 void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success);
 
 /* Unmap a pending page and release it back to the guest */
-void xenvif_idx_unmap(struct xenvif *vif, u16 pending_idx);
+void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx);
 
-static inline pending_ring_idx_t nr_pending_reqs(struct xenvif *vif)
+static inline pending_ring_idx_t nr_pending_reqs(struct xenvif_queue *queue)
 {
 	return MAX_PENDING_REQS -
-		vif->pending_prod + vif->pending_cons;
+		queue->pending_prod + queue->pending_cons;
 }
 
 /* Callback from stack when TX packet can be released */
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index 8fdedac3fab2..6005b5d1d404 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -34,7 +34,6 @@
 #include <linux/ethtool.h>
 #include <linux/rtnetlink.h>
 #include <linux/if_vlan.h>
-#include <linux/vmalloc.h>
 
 #include <xen/events.h>
 #include <asm/xen/hypercall.h>
@@ -43,6 +42,16 @@
 #define XENVIF_QUEUE_LENGTH 32
 #define XENVIF_NAPI_WEIGHT  64
 
+static inline void xenvif_stop_queue(struct xenvif_queue *queue)
+{
+	struct net_device *dev = queue->vif->dev;
+
+	if (!queue->vif->can_queue)
+		return;
+
+	netif_tx_stop_queue(netdev_get_tx_queue(dev, queue->id));
+}
+
 int xenvif_schedulable(struct xenvif *vif)
 {
 	return netif_running(vif->dev) && netif_carrier_ok(vif->dev);
@@ -50,33 +59,34 @@ int xenvif_schedulable(struct xenvif *vif)
 
 static irqreturn_t xenvif_tx_interrupt(int irq, void *dev_id)
 {
-	struct xenvif *vif = dev_id;
+	struct xenvif_queue *queue = dev_id;
 
-	if (RING_HAS_UNCONSUMED_REQUESTS(&vif->tx))
-		napi_schedule(&vif->napi);
+	if (RING_HAS_UNCONSUMED_REQUESTS(&queue->tx))
+		napi_schedule(&queue->napi);
 
 	return IRQ_HANDLED;
 }
 
-static int xenvif_poll(struct napi_struct *napi, int budget)
+int xenvif_poll(struct napi_struct *napi, int budget)
 {
-	struct xenvif *vif = container_of(napi, struct xenvif, napi);
+	struct xenvif_queue *queue =
+		container_of(napi, struct xenvif_queue, napi);
 	int work_done;
 
 	/* This vif is rogue, we pretend we've there is nothing to do
 	 * for this vif to deschedule it from NAPI. But this interface
 	 * will be turned off in thread context later.
 	 */
-	if (unlikely(vif->disabled)) {
+	if (unlikely(queue->vif->disabled)) {
 		napi_complete(napi);
 		return 0;
 	}
 
-	work_done = xenvif_tx_action(vif, budget);
+	work_done = xenvif_tx_action(queue, budget);
 
 	if (work_done < budget) {
 		napi_complete(napi);
-		xenvif_napi_schedule_or_enable_events(vif);
+		xenvif_napi_schedule_or_enable_events(queue);
 	}
 
 	return work_done;
@@ -84,9 +94,9 @@ static int xenvif_poll(struct napi_struct *napi, int budget)
 
 static irqreturn_t xenvif_rx_interrupt(int irq, void *dev_id)
 {
-	struct xenvif *vif = dev_id;
+	struct xenvif_queue *queue = dev_id;
 
-	xenvif_kick_thread(vif);
+	xenvif_kick_thread(queue);
 
 	return IRQ_HANDLED;
 }
@@ -99,28 +109,81 @@ static irqreturn_t xenvif_interrupt(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
-static void xenvif_wake_queue(unsigned long data)
+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));
+}
+
+/* Callback to wake the queue and drain it on timeout */
+static void xenvif_wake_queue_callback(unsigned long data)
 {
-	struct xenvif *vif = (struct xenvif *)data;
+	struct xenvif_queue *queue = (struct xenvif_queue *)data;
+
+	if (xenvif_queue_stopped(queue)) {
+		netdev_err(queue->vif->dev, "draining TX queue\n");
+		queue->rx_queue_purge = true;
+		xenvif_kick_thread(queue);
+		xenvif_wake_queue(queue);
+	}
+}
 
-	if (netif_queue_stopped(vif->dev)) {
-		netdev_err(vif->dev, "draining TX queue\n");
-		vif->rx_queue_purge = true;
-		xenvif_kick_thread(vif);
-		netif_wake_queue(vif->dev);
+static u16 xenvif_select_queue(struct net_device *dev, struct sk_buff *skb,
+			       void *accel_priv, select_queue_fallback_t fallback)
+{
+	struct xenvif *vif = netdev_priv(dev);
+	unsigned int num_queues = dev->real_num_tx_queues;
+	u32 hash;
+	u16 queue_index;
+
+	/* First, check if there is only one queue to optimise the
+	 * single-queue or old frontend scenario.
+	 */
+	if (num_queues == 1) {
+		queue_index = 0;
+	} else {
+		/* Use skb_get_hash to obtain an L4 hash if available */
+		hash = skb_get_hash(skb);
+		queue_index = hash % num_queues;
 	}
+
+	return queue_index;
 }
 
 static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct xenvif *vif = netdev_priv(dev);
+	struct xenvif_queue *queue = NULL;
+	unsigned int num_queues = dev->real_num_tx_queues;
+	u16 index;
 	int min_slots_needed;
 
 	BUG_ON(skb->dev != dev);
 
-	/* Drop the packet if vif is not ready */
-	if (vif->task == NULL ||
-	    vif->dealloc_task == NULL ||
+	/* Drop the packet if queues are not set up */
+	if (num_queues < 1)
+		goto drop;
+
+	/* Obtain the queue to be used to transmit this packet */
+	index = skb_get_queue_mapping(skb);
+	if (index >= num_queues) {
+		pr_warn_ratelimited("Invalid queue %hu for packet on interface %s\n.",
+				    index, vif->dev->name);
+		index %= num_queues;
+	}
+	queue = &vif->queues[index];
+
+	/* Drop the packet if queue is not ready */
+	if (queue->task == NULL ||
+	    queue->dealloc_task == NULL ||
 	    !xenvif_schedulable(vif))
 		goto drop;
 
@@ -139,16 +202,16 @@ static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	 * then turn off the queue to give the ring a chance to
 	 * drain.
 	 */
-	if (!xenvif_rx_ring_slots_available(vif, min_slots_needed)) {
-		vif->wake_queue.function = xenvif_wake_queue;
-		vif->wake_queue.data = (unsigned long)vif;
-		xenvif_stop_queue(vif);
-		mod_timer(&vif->wake_queue,
+	if (!xenvif_rx_ring_slots_available(queue, min_slots_needed)) {
+		queue->wake_queue.function = xenvif_wake_queue_callback;
+		queue->wake_queue.data = (unsigned long)queue;
+		xenvif_stop_queue(queue);
+		mod_timer(&queue->wake_queue,
 			jiffies + rx_drain_timeout_jiffies);
 	}
 
-	skb_queue_tail(&vif->rx_queue, skb);
-	xenvif_kick_thread(vif);
+	skb_queue_tail(&queue->rx_queue, skb);
+	xenvif_kick_thread(queue);
 
 	return NETDEV_TX_OK;
 
@@ -161,25 +224,65 @@ static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev)
 static struct net_device_stats *xenvif_get_stats(struct net_device *dev)
 {
 	struct xenvif *vif = netdev_priv(dev);
+	struct xenvif_queue *queue = NULL;
+	unsigned int num_queues = dev->real_num_tx_queues;
+	unsigned long rx_bytes = 0;
+	unsigned long rx_packets = 0;
+	unsigned long tx_bytes = 0;
+	unsigned long tx_packets = 0;
+	unsigned int index;
+
+	if (vif->queues == NULL)
+		goto out;
+
+	/* Aggregate tx and rx stats from each queue */
+	for (index = 0; index < num_queues; ++index) {
+		queue = &vif->queues[index];
+		rx_bytes += queue->stats.rx_bytes;
+		rx_packets += queue->stats.rx_packets;
+		tx_bytes += queue->stats.tx_bytes;
+		tx_packets += queue->stats.tx_packets;
+	}
+
+out:
+	vif->dev->stats.rx_bytes = rx_bytes;
+	vif->dev->stats.rx_packets = rx_packets;
+	vif->dev->stats.tx_bytes = tx_bytes;
+	vif->dev->stats.tx_packets = tx_packets;
+
 	return &vif->dev->stats;
 }
 
 static void xenvif_up(struct xenvif *vif)
 {
-	napi_enable(&vif->napi);
-	enable_irq(vif->tx_irq);
-	if (vif->tx_irq != vif->rx_irq)
-		enable_irq(vif->rx_irq);
-	xenvif_napi_schedule_or_enable_events(vif);
+	struct xenvif_queue *queue = NULL;
+	unsigned int num_queues = vif->dev->real_num_tx_queues;
+	unsigned int queue_index;
+
+	for (queue_index = 0; queue_index < num_queues; ++queue_index) {
+		queue = &vif->queues[queue_index];
+		napi_enable(&queue->napi);
+		enable_irq(queue->tx_irq);
+		if (queue->tx_irq != queue->rx_irq)
+			enable_irq(queue->rx_irq);
+		xenvif_napi_schedule_or_enable_events(queue);
+	}
 }
 
 static void xenvif_down(struct xenvif *vif)
 {
-	napi_disable(&vif->napi);
-	disable_irq(vif->tx_irq);
-	if (vif->tx_irq != vif->rx_irq)
-		disable_irq(vif->rx_irq);
-	del_timer_sync(&vif->credit_timeout);
+	struct xenvif_queue *queue = NULL;
+	unsigned int num_queues = vif->dev->real_num_tx_queues;
+	unsigned int queue_index;
+
+	for (queue_index = 0; queue_index < num_queues; ++queue_index) {
+		queue = &vif->queues[queue_index];
+		napi_disable(&queue->napi);
+		disable_irq(queue->tx_irq);
+		if (queue->tx_irq != queue->rx_irq)
+			disable_irq(queue->rx_irq);
+		del_timer_sync(&queue->credit_timeout);
+	}
 }
 
 static int xenvif_open(struct net_device *dev)
@@ -187,7 +290,7 @@ static int xenvif_open(struct net_device *dev)
 	struct xenvif *vif = netdev_priv(dev);
 	if (netif_carrier_ok(dev))
 		xenvif_up(vif);
-	netif_start_queue(dev);
+	netif_tx_start_all_queues(dev);
 	return 0;
 }
 
@@ -196,7 +299,7 @@ static int xenvif_close(struct net_device *dev)
 	struct xenvif *vif = netdev_priv(dev);
 	if (netif_carrier_ok(dev))
 		xenvif_down(vif);
-	netif_stop_queue(dev);
+	netif_tx_stop_all_queues(dev);
 	return 0;
 }
 
@@ -236,29 +339,29 @@ static const struct xenvif_stat {
 } xenvif_stats[] = {
 	{
 		"rx_gso_checksum_fixup",
-		offsetof(struct xenvif, rx_gso_checksum_fixup)
+		offsetof(struct xenvif_stats, rx_gso_checksum_fixup)
 	},
 	/* If (sent != success + fail), there are probably packets never
 	 * freed up properly!
 	 */
 	{
 		"tx_zerocopy_sent",
-		offsetof(struct xenvif, tx_zerocopy_sent),
+		offsetof(struct xenvif_stats, tx_zerocopy_sent),
 	},
 	{
 		"tx_zerocopy_success",
-		offsetof(struct xenvif, tx_zerocopy_success),
+		offsetof(struct xenvif_stats, tx_zerocopy_success),
 	},
 	{
 		"tx_zerocopy_fail",
-		offsetof(struct xenvif, tx_zerocopy_fail)
+		offsetof(struct xenvif_stats, tx_zerocopy_fail)
 	},
 	/* Number of packets exceeding MAX_SKB_FRAG slots. You should use
 	 * a guest with the same MAX_SKB_FRAG
 	 */
 	{
 		"tx_frag_overflow",
-		offsetof(struct xenvif, tx_frag_overflow)
+		offsetof(struct xenvif_stats, tx_frag_overflow)
 	},
 };
 
@@ -275,11 +378,20 @@ static int xenvif_get_sset_count(struct net_device *dev, int string_set)
 static void xenvif_get_ethtool_stats(struct net_device *dev,
 				     struct ethtool_stats *stats, u64 * data)
 {
-	void *vif = netdev_priv(dev);
+	struct xenvif *vif = netdev_priv(dev);
+	unsigned int num_queues = dev->real_num_tx_queues;
 	int i;
-
-	for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
-		data[i] = *(unsigned long *)(vif + xenvif_stats[i].offset);
+	unsigned int queue_index;
+	struct xenvif_stats *vif_stats;
+
+	for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++) {
+		unsigned long accum = 0;
+		for (queue_index = 0; queue_index < num_queues; ++queue_index) {
+			vif_stats = &vif->queues[queue_index].stats;
+			accum += *(unsigned long *)(vif_stats + xenvif_stats[i].offset);
+		}
+		data[i] = accum;
+	}
 }
 
 static void xenvif_get_strings(struct net_device *dev, u32 stringset, u8 * data)
@@ -312,6 +424,7 @@ static const struct net_device_ops xenvif_netdev_ops = {
 	.ndo_fix_features = xenvif_fix_features,
 	.ndo_set_mac_address = eth_mac_addr,
 	.ndo_validate_addr   = eth_validate_addr,
+	.ndo_select_queue = xenvif_select_queue,
 };
 
 struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
@@ -321,10 +434,9 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
 	struct net_device *dev;
 	struct xenvif *vif;
 	char name[IFNAMSIZ] = {};
-	int i;
 
 	snprintf(name, IFNAMSIZ - 1, "vif%u.%u", domid, handle);
-	dev = alloc_netdev(sizeof(struct xenvif), name, ether_setup);
+	dev = alloc_netdev_mq(sizeof(struct xenvif), name, ether_setup, 1);
 	if (dev == NULL) {
 		pr_warn("Could not allocate netdev for %s\n", name);
 		return ERR_PTR(-ENOMEM);
@@ -339,15 +451,13 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
 	vif->can_sg = 1;
 	vif->ip_csum = 1;
 	vif->dev = dev;
-
 	vif->disabled = false;
 
-	vif->credit_bytes = vif->remaining_credit = ~0UL;
-	vif->credit_usec  = 0UL;
-	init_timer(&vif->credit_timeout);
-	vif->credit_window_start = get_jiffies_64();
-
-	init_timer(&vif->wake_queue);
+	/* Start out with no queues. The call below does not require
+	 * rtnl_lock() as it happens before register_netdev().
+	 */
+	vif->queues = NULL;
+	netif_set_real_num_tx_queues(dev, 0);
 
 	dev->netdev_ops	= &xenvif_netdev_ops;
 	dev->hw_features = NETIF_F_SG |
@@ -358,34 +468,6 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
 
 	dev->tx_queue_len = XENVIF_QUEUE_LENGTH;
 
-	skb_queue_head_init(&vif->rx_queue);
-	skb_queue_head_init(&vif->tx_queue);
-
-	vif->pending_cons = 0;
-	vif->pending_prod = MAX_PENDING_REQS;
-	for (i = 0; i < MAX_PENDING_REQS; i++)
-		vif->pending_ring[i] = i;
-	spin_lock_init(&vif->callback_lock);
-	spin_lock_init(&vif->response_lock);
-	/* If ballooning is disabled, this will consume real memory, so you
-	 * better enable it. The long term solution would be to use just a
-	 * bunch of valid page descriptors, without dependency on ballooning
-	 */
-	err = alloc_xenballooned_pages(MAX_PENDING_REQS,
-				       vif->mmap_pages,
-				       false);
-	if (err) {
-		netdev_err(dev, "Could not reserve mmap_pages\n");
-		return ERR_PTR(-ENOMEM);
-	}
-	for (i = 0; i < MAX_PENDING_REQS; i++) {
-		vif->pending_tx_info[i].callback_struct = (struct ubuf_info)
-			{ .callback = xenvif_zerocopy_callback,
-			  .ctx = NULL,
-			  .desc = i };
-		vif->grant_tx_handle[i] = NETBACK_INVALID_HANDLE;
-	}
-
 	/*
 	 * Initialise a dummy MAC address. We choose the numerically
 	 * largest non-broadcast address to prevent the address getting
@@ -395,8 +477,6 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
 	memset(dev->dev_addr, 0xFF, ETH_ALEN);
 	dev->dev_addr[0] &= ~0x01;
 
-	netif_napi_add(dev, &vif->napi, xenvif_poll, XENVIF_NAPI_WEIGHT);
-
 	netif_carrier_off(dev);
 
 	err = register_netdev(dev);
@@ -413,98 +493,147 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
 	return vif;
 }
 
-int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
+int xenvif_init_queue(struct xenvif_queue *queue)
+{
+	int err, i;
+
+	queue->credit_bytes = queue->remaining_credit = ~0UL;
+	queue->credit_usec  = 0UL;
+	init_timer(&queue->credit_timeout);
+	queue->credit_window_start = get_jiffies_64();
+
+	skb_queue_head_init(&queue->rx_queue);
+	skb_queue_head_init(&queue->tx_queue);
+
+	queue->pending_cons = 0;
+	queue->pending_prod = MAX_PENDING_REQS;
+	for (i = 0; i < MAX_PENDING_REQS; ++i)
+		queue->pending_ring[i] = i;
+
+	spin_lock_init(&queue->callback_lock);
+	spin_lock_init(&queue->response_lock);
+
+	/* If ballooning is disabled, this will consume real memory, so you
+	 * better enable it. The long term solution would be to use just a
+	 * bunch of valid page descriptors, without dependency on ballooning
+	 */
+	err = alloc_xenballooned_pages(MAX_PENDING_REQS,
+				       queue->mmap_pages,
+				       false);
+	if (err) {
+		netdev_err(queue->vif->dev, "Could not reserve mmap_pages\n");
+		return -ENOMEM;
+	}
+
+	for (i = 0; i < MAX_PENDING_REQS; i++) {
+		queue->pending_tx_info[i].callback_struct = (struct ubuf_info)
+			{ .callback = xenvif_zerocopy_callback,
+			  .ctx = NULL,
+			  .desc = i };
+		queue->grant_tx_handle[i] = NETBACK_INVALID_HANDLE;
+	}
+
+	init_timer(&queue->wake_queue);
+
+	netif_napi_add(queue->vif->dev, &queue->napi, xenvif_poll,
+			XENVIF_NAPI_WEIGHT);
+
+	return 0;
+}
+
+void xenvif_carrier_on(struct xenvif *vif)
+{
+	rtnl_lock();
+	if (!vif->can_sg && vif->dev->mtu > ETH_DATA_LEN)
+		dev_set_mtu(vif->dev, ETH_DATA_LEN);
+	netdev_update_features(vif->dev);
+	netif_carrier_on(vif->dev);
+	if (netif_running(vif->dev))
+		xenvif_up(vif);
+	rtnl_unlock();
+}
+
+int xenvif_connect(struct xenvif_queue *queue, unsigned long tx_ring_ref,
 		   unsigned long rx_ring_ref, unsigned int tx_evtchn,
 		   unsigned int rx_evtchn)
 {
 	struct task_struct *task;
 	int err = -ENOMEM;
 
-	BUG_ON(vif->tx_irq);
-	BUG_ON(vif->task);
-	BUG_ON(vif->dealloc_task);
+	BUG_ON(queue->tx_irq);
+	BUG_ON(queue->task);
+	BUG_ON(queue->dealloc_task);
 
-	err = xenvif_map_frontend_rings(vif, tx_ring_ref, rx_ring_ref);
+	err = xenvif_map_frontend_rings(queue, tx_ring_ref, rx_ring_ref);
 	if (err < 0)
 		goto err;
 
-	init_waitqueue_head(&vif->wq);
-	init_waitqueue_head(&vif->dealloc_wq);
+	init_waitqueue_head(&queue->wq);
+	init_waitqueue_head(&queue->dealloc_wq);
 
 	if (tx_evtchn == rx_evtchn) {
 		/* feature-split-event-channels == 0 */
 		err = bind_interdomain_evtchn_to_irqhandler(
-			vif->domid, tx_evtchn, xenvif_interrupt, 0,
-			vif->dev->name, vif);
+			queue->vif->domid, tx_evtchn, xenvif_interrupt, 0,
+			queue->name, queue);
 		if (err < 0)
 			goto err_unmap;
-		vif->tx_irq = vif->rx_irq = err;
-		disable_irq(vif->tx_irq);
+		queue->tx_irq = queue->rx_irq = err;
+		disable_irq(queue->tx_irq);
 	} else {
 		/* feature-split-event-channels == 1 */
-		snprintf(vif->tx_irq_name, sizeof(vif->tx_irq_name),
-			 "%s-tx", vif->dev->name);
+		snprintf(queue->tx_irq_name, sizeof(queue->tx_irq_name),
+			 "%s-tx", queue->name);
 		err = bind_interdomain_evtchn_to_irqhandler(
-			vif->domid, tx_evtchn, xenvif_tx_interrupt, 0,
-			vif->tx_irq_name, vif);
+			queue->vif->domid, tx_evtchn, xenvif_tx_interrupt, 0,
+			queue->tx_irq_name, queue);
 		if (err < 0)
 			goto err_unmap;
-		vif->tx_irq = err;
-		disable_irq(vif->tx_irq);
+		queue->tx_irq = err;
+		disable_irq(queue->tx_irq);
 
-		snprintf(vif->rx_irq_name, sizeof(vif->rx_irq_name),
-			 "%s-rx", vif->dev->name);
+		snprintf(queue->rx_irq_name, sizeof(queue->rx_irq_name),
+			 "%s-rx", queue->name);
 		err = bind_interdomain_evtchn_to_irqhandler(
-			vif->domid, rx_evtchn, xenvif_rx_interrupt, 0,
-			vif->rx_irq_name, vif);
+			queue->vif->domid, rx_evtchn, xenvif_rx_interrupt, 0,
+			queue->rx_irq_name, queue);
 		if (err < 0)
 			goto err_tx_unbind;
-		vif->rx_irq = err;
-		disable_irq(vif->rx_irq);
+		queue->rx_irq = err;
+		disable_irq(queue->rx_irq);
 	}
 
 	task = kthread_create(xenvif_kthread_guest_rx,
-			      (void *)vif, "%s-guest-rx", vif->dev->name);
+			      (void *)queue, "%s-guest-rx", queue->name);
 	if (IS_ERR(task)) {
-		pr_warn("Could not allocate kthread for %s\n", vif->dev->name);
+		pr_warn("Could not allocate kthread for %s\n", queue->name);
 		err = PTR_ERR(task);
 		goto err_rx_unbind;
 	}
-
-	vif->task = task;
+	queue->task = task;
 
 	task = kthread_create(xenvif_dealloc_kthread,
-			      (void *)vif, "%s-dealloc", vif->dev->name);
+			      (void *)queue, "%s-dealloc", queue->name);
 	if (IS_ERR(task)) {
-		pr_warn("Could not allocate kthread for %s\n", vif->dev->name);
+		pr_warn("Could not allocate kthread for %s\n", queue->name);
 		err = PTR_ERR(task);
 		goto err_rx_unbind;
 	}
+	queue->dealloc_task = task;
 
-	vif->dealloc_task = task;
-
-	rtnl_lock();
-	if (!vif->can_sg && vif->dev->mtu > ETH_DATA_LEN)
-		dev_set_mtu(vif->dev, ETH_DATA_LEN);
-	netdev_update_features(vif->dev);
-	netif_carrier_on(vif->dev);
-	if (netif_running(vif->dev))
-		xenvif_up(vif);
-	rtnl_unlock();
-
-	wake_up_process(vif->task);
-	wake_up_process(vif->dealloc_task);
+	wake_up_process(queue->task);
+	wake_up_process(queue->dealloc_task);
 
 	return 0;
 
 err_rx_unbind:
-	unbind_from_irqhandler(vif->rx_irq, vif);
-	vif->rx_irq = 0;
+	unbind_from_irqhandler(queue->rx_irq, queue);
+	queue->rx_irq = 0;
 err_tx_unbind:
-	unbind_from_irqhandler(vif->tx_irq, vif);
-	vif->tx_irq = 0;
+	unbind_from_irqhandler(queue->tx_irq, queue);
+	queue->tx_irq = 0;
 err_unmap:
-	xenvif_unmap_frontend_rings(vif);
+	xenvif_unmap_frontend_rings(queue);
 err:
 	module_put(THIS_MODULE);
 	return err;
@@ -521,38 +650,67 @@ void xenvif_carrier_off(struct xenvif *vif)
 	rtnl_unlock();
 }
 
+static void xenvif_wait_unmap_timeout(struct xenvif_queue *queue,
+				      unsigned int worst_case_skb_lifetime)
+{
+	int i, unmap_timeout = 0;
+
+	for (i = 0; i < MAX_PENDING_REQS; ++i) {
+		if (queue->grant_tx_handle[i] != NETBACK_INVALID_HANDLE) {
+			unmap_timeout++;
+			schedule_timeout(msecs_to_jiffies(1000));
+			if (unmap_timeout > worst_case_skb_lifetime &&
+			    net_ratelimit())
+				netdev_err(queue->vif->dev,
+					   "Page still granted! Index: %x\n",
+					   i);
+			i = -1;
+		}
+	}
+}
+
 void xenvif_disconnect(struct xenvif *vif)
 {
+	struct xenvif_queue *queue = NULL;
+	unsigned int num_queues = vif->dev->real_num_tx_queues;
+	unsigned int queue_index;
+
 	if (netif_carrier_ok(vif->dev))
 		xenvif_carrier_off(vif);
 
-	if (vif->task) {
-		del_timer_sync(&vif->wake_queue);
-		kthread_stop(vif->task);
-		vif->task = NULL;
-	}
+	for (queue_index = 0; queue_index < num_queues; ++queue_index) {
+		queue = &vif->queues[queue_index];
 
-	if (vif->dealloc_task) {
-		kthread_stop(vif->dealloc_task);
-		vif->dealloc_task = NULL;
-	}
+		if (queue->task) {
+			del_timer_sync(&queue->wake_queue);
+			kthread_stop(queue->task);
+			queue->task = NULL;
+		}
 
-	if (vif->tx_irq) {
-		if (vif->tx_irq == vif->rx_irq)
-			unbind_from_irqhandler(vif->tx_irq, vif);
-		else {
-			unbind_from_irqhandler(vif->tx_irq, vif);
-			unbind_from_irqhandler(vif->rx_irq, vif);
+		if (queue->dealloc_task) {
+			kthread_stop(queue->dealloc_task);
+			queue->dealloc_task = NULL;
+		}
+
+		if (queue->tx_irq) {
+			if (queue->tx_irq == queue->rx_irq)
+				unbind_from_irqhandler(queue->tx_irq, queue);
+			else {
+				unbind_from_irqhandler(queue->tx_irq, queue);
+				unbind_from_irqhandler(queue->rx_irq, queue);
+			}
+			queue->tx_irq = 0;
 		}
-		vif->tx_irq = 0;
-	}
 
-	xenvif_unmap_frontend_rings(vif);
+		xenvif_unmap_frontend_rings(queue);
+	}
 }
 
 void xenvif_free(struct xenvif *vif)
 {
-	int i, unmap_timeout = 0;
+	struct xenvif_queue *queue = NULL;
+	unsigned int num_queues = vif->dev->real_num_tx_queues;
+	unsigned int queue_index;
 	/* Here we want to avoid timeout messages if an skb can be legitimately
 	 * stuck somewhere else. Realistically this could be an another vif's
 	 * internal or QDisc queue. That another vif also has this
@@ -567,31 +725,23 @@ void xenvif_free(struct xenvif *vif)
 	unsigned int worst_case_skb_lifetime = (rx_drain_timeout_msecs/1000) *
 		DIV_ROUND_UP(XENVIF_QUEUE_LENGTH, (XEN_NETIF_RX_RING_SIZE / MAX_SKB_FRAGS));
 
-	for (i = 0; i < MAX_PENDING_REQS; ++i) {
-		if (vif->grant_tx_handle[i] != NETBACK_INVALID_HANDLE) {
-			unmap_timeout++;
-			schedule_timeout(msecs_to_jiffies(1000));
-			if (unmap_timeout > worst_case_skb_lifetime &&
-			    net_ratelimit())
-				netdev_err(vif->dev,
-					   "Page still granted! Index: %x\n",
-					   i);
-			/* If there are still unmapped pages, reset the loop to
-			 * start checking again. We shouldn't exit here until
-			 * dealloc thread and NAPI instance release all the
-			 * pages. If a kernel bug causes the skbs to stall
-			 * somewhere, the interface cannot be brought down
-			 * properly.
-			 */
-			i = -1;
-		}
-	}
+	unregister_netdev(vif->dev);
 
-	free_xenballooned_pages(MAX_PENDING_REQS, vif->mmap_pages);
+	for (queue_index = 0; queue_index < num_queues; ++queue_index) {
+		queue = &vif->queues[queue_index];
 
-	netif_napi_del(&vif->napi);
+		xenvif_wait_unmap_timeout(queue, worst_case_skb_lifetime);
+		free_xenballooned_pages(MAX_PENDING_REQS, queue->mmap_pages);
 
-	unregister_netdev(vif->dev);
+		netif_napi_del(&queue->napi);
+	}
+
+	/* Free the array of queues. The call below does not require
+	 * rtnl_lock() because it happens after unregister_netdev().
+	 */
+	netif_set_real_num_tx_queues(vif->dev, 0);
+	vfree(vif->queues);
+	vif->queues = NULL;
 
 	free_netdev(vif->dev);
 
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 7367208ee8cd..a5484e8cb06e 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -70,33 +70,33 @@ unsigned int rx_drain_timeout_jiffies;
 static unsigned int fatal_skb_slots = FATAL_SKB_SLOTS_DEFAULT;
 module_param(fatal_skb_slots, uint, 0444);
 
-static void xenvif_idx_release(struct xenvif *vif, u16 pending_idx,
+static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
 			       u8 status);
 
-static void make_tx_response(struct xenvif *vif,
+static void make_tx_response(struct xenvif_queue *queue,
 			     struct xen_netif_tx_request *txp,
 			     s8       st);
 
-static inline int tx_work_todo(struct xenvif *vif);
-static inline int rx_work_todo(struct xenvif *vif);
+static inline int tx_work_todo(struct xenvif_queue *queue);
+static inline int rx_work_todo(struct xenvif_queue *queue);
 
-static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif,
+static struct xen_netif_rx_response *make_rx_response(struct xenvif_queue *queue,
 					     u16      id,
 					     s8       st,
 					     u16      offset,
 					     u16      size,
 					     u16      flags);
 
-static inline unsigned long idx_to_pfn(struct xenvif *vif,
+static inline unsigned long idx_to_pfn(struct xenvif_queue *queue,
 				       u16 idx)
 {
-	return page_to_pfn(vif->mmap_pages[idx]);
+	return page_to_pfn(queue->mmap_pages[idx]);
 }
 
-static inline unsigned long idx_to_kaddr(struct xenvif *vif,
+static inline unsigned long idx_to_kaddr(struct xenvif_queue *queue,
 					 u16 idx)
 {
-	return (unsigned long)pfn_to_kaddr(idx_to_pfn(vif, idx));
+	return (unsigned long)pfn_to_kaddr(idx_to_pfn(queue, idx));
 }
 
 #define callback_param(vif, pending_idx) \
@@ -104,13 +104,13 @@ static inline unsigned long idx_to_kaddr(struct xenvif *vif,
 
 /* Find the containing VIF's structure from a pointer in pending_tx_info array
  */
-static inline struct xenvif *ubuf_to_vif(const struct ubuf_info *ubuf)
+static inline struct xenvif_queue *ubuf_to_queue(const struct ubuf_info *ubuf)
 {
 	u16 pending_idx = ubuf->desc;
 	struct pending_tx_info *temp =
 		container_of(ubuf, struct pending_tx_info, callback_struct);
 	return container_of(temp - pending_idx,
-			    struct xenvif,
+			    struct xenvif_queue,
 			    pending_tx_info[0]);
 }
 
@@ -136,24 +136,24 @@ static inline pending_ring_idx_t pending_index(unsigned i)
 	return i & (MAX_PENDING_REQS-1);
 }
 
-bool xenvif_rx_ring_slots_available(struct xenvif *vif, int needed)
+bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue, int needed)
 {
 	RING_IDX prod, cons;
 
 	do {
-		prod = vif->rx.sring->req_prod;
-		cons = vif->rx.req_cons;
+		prod = queue->rx.sring->req_prod;
+		cons = queue->rx.req_cons;
 
 		if (prod - cons >= needed)
 			return true;
 
-		vif->rx.sring->req_event = prod + 1;
+		queue->rx.