1 files changed, 175 insertions, 50 deletions

diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index 1db101415069..76a22365d4e9 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -85,7 +85,15 @@ struct netfront_info {
 
 	struct napi_struct napi;
 
-	unsigned int evtchn;
+	/* Split event channels support, tx_* == rx_* when using
+	 * single event channel.
+	 */
+	unsigned int tx_evtchn, rx_evtchn;
+	unsigned int tx_irq, rx_irq;
+	/* Only used when split event channels support is enabled */
+	char tx_irq_name[IFNAMSIZ+4]; /* DEVNAME-tx */
+	char rx_irq_name[IFNAMSIZ+4]; /* DEVNAME-rx */
+
 	struct xenbus_device *xbdev;
 
 	spinlock_t   tx_lock;
@@ -330,7 +338,7 @@ no_skb:
  push:
 	RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&np->rx, notify);
 	if (notify)
-		notify_remote_via_irq(np->netdev->irq);
+		notify_remote_via_irq(np->rx_irq);
 }
 
 static int xennet_open(struct net_device *dev)
@@ -623,7 +631,7 @@ static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
 
 	RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&np->tx, notify);
 	if (notify)
-		notify_remote_via_irq(np->netdev->irq);
+		notify_remote_via_irq(np->tx_irq);
 
 	u64_stats_update_begin(&stats->syncp);
 	stats->tx_bytes += skb->len;
@@ -850,7 +858,6 @@ static RING_IDX xennet_fill_frags(struct netfront_info *np,
 static int checksum_setup(struct net_device *dev, struct sk_buff *skb)
 {
 	struct iphdr *iph;
-	unsigned char *th;
 	int err = -EPROTO;
 	int recalculate_partial_csum = 0;
 
@@ -875,27 +882,27 @@ static int checksum_setup(struct net_device *dev, struct sk_buff *skb)
 		goto out;
 
 	iph = (void *)skb->data;
-	th = skb->data + 4 * iph->ihl;
-	if (th >= skb_tail_pointer(skb))
-		goto out;
 
-	skb->csum_start = th - skb->head;
 	switch (iph->protocol) {
 	case IPPROTO_TCP:
-		skb->csum_offset = offsetof(struct tcphdr, check);
+		if (!skb_partial_csum_set(skb, 4 * iph->ihl,
+					  offsetof(struct tcphdr, check)))
+			goto out;
 
 		if (recalculate_partial_csum) {
-			struct tcphdr *tcph = (struct tcphdr *)th;
+			struct tcphdr *tcph = tcp_hdr(skb);
 			tcph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
 							 skb->len - iph->ihl*4,
 							 IPPROTO_TCP, 0);
 		}
 		break;
 	case IPPROTO_UDP:
-		skb->csum_offset = offsetof(struct udphdr, check);
+		if (!skb_partial_csum_set(skb, 4 * iph->ihl,
+					  offsetof(struct udphdr, check)))
+			goto out;
 
 		if (recalculate_partial_csum) {
-			struct udphdr *udph = (struct udphdr *)th;
+			struct udphdr *udph = udp_hdr(skb);
 			udph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
 							 skb->len - iph->ihl*4,
 							 IPPROTO_UDP, 0);
@@ -909,9 +916,6 @@ static int checksum_setup(struct net_device *dev, struct sk_buff *skb)
 		goto out;
 	}
 
-	if ((th + skb->csum_offset + 2) > skb_tail_pointer(skb))
-		goto out;
-
 	err = 0;
 
 out:
@@ -1254,23 +1258,35 @@ static int xennet_set_features(struct net_device *dev,
 	return 0;
 }
 
-static irqreturn_t xennet_interrupt(int irq, void *dev_id)
+static irqreturn_t xennet_tx_interrupt(int irq, void *dev_id)
 {
-	struct net_device *dev = dev_id;
-	struct netfront_info *np = netdev_priv(dev);
+	struct netfront_info *np = dev_id;
+	struct net_device *dev = np->netdev;
 	unsigned long flags;
 
 	spin_lock_irqsave(&np->tx_lock, flags);
+	xennet_tx_buf_gc(dev);
+	spin_unlock_irqrestore(&np->tx_lock, flags);
 
-	if (likely(netif_carrier_ok(dev))) {
-		xennet_tx_buf_gc(dev);
-		/* Under tx_lock: protects access to rx shared-ring indexes. */
-		if (RING_HAS_UNCONSUMED_RESPONSES(&np->rx))
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t xennet_rx_interrupt(int irq, void *dev_id)
+{
+	struct netfront_info *np = dev_id;
+	struct net_device *dev = np->netdev;
+
+	if (likely(netif_carrier_ok(dev) &&
+		   RING_HAS_UNCONSUMED_RESPONSES(&np->rx)))
 			napi_schedule(&np->napi);
-	}
 
-	spin_unlock_irqrestore(&np->tx_lock, flags);
+	return IRQ_HANDLED;
+}
 
+static irqreturn_t xennet_interrupt(int irq, void *dev_id)
+{
+	xennet_tx_interrupt(irq, dev_id);
+	xennet_rx_interrupt(irq, dev_id);
 	return IRQ_HANDLED;
 }
 
@@ -1451,9 +1467,14 @@ static void xennet_disconnect_backend(struct netfront_info *info)
 	spin_unlock_irq(&info->tx_lock);
 	spin_unlock_bh(&info->rx_lock);
 
-	if (info->netdev->irq)
-		unbind_from_irqhandler(info->netdev->irq, info->netdev);
-	info->evtchn = info->netdev->irq = 0;
+	if (info->tx_irq && (info->tx_irq == info->rx_irq))
+		unbind_from_irqhandler(info->tx_irq, info);
+	if (info->tx_irq && (info->tx_irq != info->rx_irq)) {
+		unbind_from_irqhandler(info->tx_irq, info);
+		unbind_from_irqhandler(info->rx_irq, info);
+	}
+	info->tx_evtchn = info->rx_evtchn = 0;
+	info->tx_irq = info->rx_irq = 0;
 
 	/* End access and free the pages */
 	xennet_end_access(info->tx_ring_ref, info->tx.sring);
@@ -1503,12 +1524,82 @@ static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
 	return 0;
 }
 
+static int setup_netfront_single(struct netfront_info *info)
+{
+	int err;
+
+	err = xenbus_alloc_evtchn(info->xbdev, &info->tx_evtchn);
+	if (err < 0)
+		goto fail;
+
+	err = bind_evtchn_to_irqhandler(info->tx_evtchn,
+					xennet_interrupt,
+					0, info->netdev->name, info);
+	if (err < 0)
+		goto bind_fail;
+	info->rx_evtchn = info->tx_evtchn;
+	info->rx_irq = info->tx_irq = err;
+
+	return 0;
+
+bind_fail:
+	xenbus_free_evtchn(info->xbdev, info->tx_evtchn);
+	info->tx_evtchn = 0;
+fail:
+	return err;
+}
+
+static int setup_netfront_split(struct netfront_info *info)
+{
+	int err;
+
+	err = xenbus_alloc_evtchn(info->xbdev, &info->tx_evtchn);
+	if (err < 0)
+		goto fail;
+	err = xenbus_alloc_evtchn(info->xbdev, &info->rx_evtchn);
+	if (err < 0)
+		goto alloc_rx_evtchn_fail;
+
+	snprintf(info->tx_irq_name, sizeof(info->tx_irq_name),
+		 "%s-tx", info->netdev->name);
+	err = bind_evtchn_to_irqhandler(info->tx_evtchn,
+					xennet_tx_interrupt,
+					0, info->tx_irq_name, info);
+	if (err < 0)
+		goto bind_tx_fail;
+	info->tx_irq = err;
+
+	snprintf(info->rx_irq_name, sizeof(info->rx_irq_name),
+		 "%s-rx", info->netdev->name);
+	err = bind_evtchn_to_irqhandler(info->rx_evtchn,
+					xennet_rx_interrupt,
+					0, info->rx_irq_name, info);
+	if (err < 0)
+		goto bind_rx_fail;
+	info->rx_irq = err;
+
+	return 0;
+
+bind_rx_fail:
+	unbind_from_irqhandler(info->tx_irq, info);
+	info->tx_irq = 0;
+bind_tx_fail:
+	xenbus_free_evtchn(info->xbdev, info->rx_evtchn);
+	info->rx_evtchn = 0;
+alloc_rx_evtchn_fail:
+	xenbus_free_evtchn(info->xbdev, info->tx_evtchn);
+	info->tx_evtchn = 0;
+fail:
+	return err;
+}
+
 static int setup_netfront(struct xenbus_device *dev, struct netfront_info *info)
 {
 	struct xen_netif_tx_sring *txs;
 	struct xen_netif_rx_sring *rxs;
 	int err;
 	struct net_device *netdev = info->netdev;
+	unsigned int feature_split_evtchn;
 
 	info->tx_ring_ref = GRANT_INVALID_REF;
 	info->rx_ring_ref = GRANT_INVALID_REF;
@@ -1516,6 +1607,12 @@ static int setup_netfront(struct xenbus_device *dev, struct netfront_info *info)
 	info->tx.sring = NULL;
 	netdev->irq = 0;
 
+	err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
+			   "feature-split-event-channels", "%u",
+			   &feature_split_evtchn);
+	if (err < 0)
+		feature_split_evtchn = 0;
+
 	err = xen_net_read_mac(dev, netdev->dev_addr);
 	if (err) {
 		xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
@@ -1532,40 +1629,50 @@ static int setup_netfront(struct xenbus_device *dev, struct netfront_info *info)
 	FRONT_RING_INIT(&info->tx, txs, PAGE_SIZE);
 
 	err = xenbus_grant_ring(dev, virt_to_mfn(txs));
-	if (err < 0) {
-		free_page((unsigned long)txs);
-		goto fail;
-	}
+	if (err < 0)
+		goto grant_tx_ring_fail;
 
 	info->tx_ring_ref = err;
 	rxs = (struct xen_netif_rx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
 	if (!rxs) {
 		err = -ENOMEM;
 		xenbus_dev_fatal(dev, err, "allocating rx ring page");
-		goto fail;
+		goto alloc_rx_ring_fail;
 	}
 	SHARED_RING_INIT(rxs);
 	FRONT_RING_INIT(&info->rx, rxs, PAGE_SIZE);
 
 	err = xenbus_grant_ring(dev, virt_to_mfn(rxs));
-	if (err < 0) {
-		free_page((unsigned long)rxs);
-		goto fail;
-	}
+	if (err < 0)
+		goto grant_rx_ring_fail;
 	info->rx_ring_ref = err;
 
-	err = xenbus_alloc_evtchn(dev, &info->evtchn);
+	if (feature_split_evtchn)
+		err = setup_netfront_split(info);
+	/* setup single event channel if
+	 *  a) feature-split-event-channels == 0
+	 *  b) feature-split-event-channels == 1 but failed to setup
+	 */
+	if (!feature_split_evtchn || (feature_split_evtchn && err))
+		err = setup_netfront_single(info);
+
 	if (err)
-		goto fail;
+		goto alloc_evtchn_fail;
 
-	err = bind_evtchn_to_irqhandler(info->evtchn, xennet_interrupt,
-					0, netdev->name, netdev);
-	if (err < 0)
-		goto fail;
-	netdev->irq = err;
 	return 0;
 
- fail:
+	/* If we fail to setup netfront, it is safe to just revoke access to
+	 * granted pages because backend is not accessing it at this point.
+	 */
+alloc_evtchn_fail:
+	gnttab_end_foreign_access_ref(info->rx_ring_ref, 0);
+grant_rx_ring_fail:
+	free_page((unsigned long)rxs);
+alloc_rx_ring_fail:
+	gnttab_end_foreign_access_ref(info->tx_ring_ref, 0);
+grant_tx_ring_fail:
+	free_page((unsigned long)txs);
+fail:
 	return err;
 }
 
@@ -1601,11 +1708,27 @@ again:
 		message = "writing rx ring-ref";
 		goto abort_transaction;
 	}
-	err = xenbus_printf(xbt, dev->nodename,
-			    "event-channel", "%u", info->evtchn);
-	if (err) {
-		message = "writing event-channel";
-		goto abort_transaction;
+
+	if (info->tx_evtchn == info->rx_evtchn) {
+		err = xenbus_printf(xbt, dev->nodename,
+				    "event-channel", "%u", info->tx_evtchn);
+		if (err) {
+			message = "writing event-channel";
+			goto abort_transaction;
+		}
+	} else {
+		err = xenbus_printf(xbt, dev->nodename,
+				    "event-channel-tx", "%u", info->tx_evtchn);
+		if (err) {
+			message = "writing event-channel-tx";
+			goto abort_transaction;
+		}
+		err = xenbus_printf(xbt, dev->nodename,
+				    "event-channel-rx", "%u", info->rx_evtchn);
+		if (err) {
+			message = "writing event-channel-rx";
+			goto abort_transaction;
+		}
 	}
 
 	err = xenbus_printf(xbt, dev->nodename, "request-rx-copy", "%u",
@@ -1718,7 +1841,9 @@ static int xennet_connect(struct net_device *dev)
 	 * packets.
 	 */
 	netif_carrier_on(np->netdev);
-	notify_remote_via_irq(np->netdev->irq);
+	notify_remote_via_irq(np->tx_irq);
+	if (np->tx_irq != np->rx_irq)
+		notify_remote_via_irq(np->rx_irq);
 	xennet_tx_buf_gc(dev);
 	xennet_alloc_rx_buffers(dev);