3 files changed, 126 insertions, 33 deletions

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 0333ab0fd..f44b38846 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -52,6 +52,7 @@ typedef unsigned int pending_ring_idx_t;
 
 struct pending_tx_info {
 	struct xen_netif_tx_request req; /* tx request */
+	unsigned int extra_count;
 	/* Callback data for released SKBs. The callback is always
 	 * xenvif_zerocopy_callback, desc contains the pending_idx, which is
 	 * also an index in pending_tx_info array. It is initialized in
@@ -251,6 +252,7 @@ struct xenvif {
 	unsigned int stalled_queues;
 
 	struct xenbus_watch credit_watch;
+	struct xenbus_watch mcast_ctrl_watch;
 
 	spinlock_t lock;
 
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 61b97c34b..4412a57ec 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -95,6 +95,7 @@ static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
 
 static void make_tx_response(struct xenvif_queue *queue,
 			     struct xen_netif_tx_request *txp,
+			     unsigned int extra_count,
 			     s8       st);
 static void push_tx_responses(struct xenvif_queue *queue);
 
@@ -696,19 +697,21 @@ void xenvif_tx_credit_callback(unsigned long data)
 }
 
 static void xenvif_tx_err(struct xenvif_queue *queue,
-			  struct xen_netif_tx_request *txp, RING_IDX end)
+			  struct xen_netif_tx_request *txp,
+			  unsigned int extra_count, RING_IDX end)
 {
 	RING_IDX cons = queue->tx.req_cons;
 	unsigned long flags;
 
 	do {
 		spin_lock_irqsave(&queue->response_lock, flags);
-		make_tx_response(queue, txp, XEN_NETIF_RSP_ERROR);
+		make_tx_response(queue, txp, extra_count, XEN_NETIF_RSP_ERROR);
 		push_tx_responses(queue);
 		spin_unlock_irqrestore(&queue->response_lock, flags);
 		if (cons == end)
 			break;
 		RING_COPY_REQUEST(&queue->tx, cons++, txp);
+		extra_count = 0; /* only the first frag can have extras */
 	} while (1);
 	queue->tx.req_cons = cons;
 }
@@ -724,6 +727,7 @@ static void xenvif_fatal_tx_err(struct xenvif *vif)
 
 static int xenvif_count_requests(struct xenvif_queue *queue,
 				 struct xen_netif_tx_request *first,
+				 unsigned int extra_count,
 				 struct xen_netif_tx_request *txp,
 				 int work_to_do)
 {
@@ -812,7 +816,7 @@ static int xenvif_count_requests(struct xenvif_queue *queue,
 	} while (more_data);
 
 	if (drop_err) {
-		xenvif_tx_err(queue, first, cons + slots);
+		xenvif_tx_err(queue, first, extra_count, cons + slots);
 		return drop_err;
 	}
 
@@ -827,9 +831,10 @@ struct xenvif_tx_cb {
 #define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb)
 
 static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue,
-					  u16 pending_idx,
-					  struct xen_netif_tx_request *txp,
-					  struct gnttab_map_grant_ref *mop)
+					   u16 pending_idx,
+					   struct xen_netif_tx_request *txp,
+					   unsigned int extra_count,
+					   struct gnttab_map_grant_ref *mop)
 {
 	queue->pages_to_map[mop-queue->tx_map_ops] = queue->mmap_pages[pending_idx];
 	gnttab_set_map_op(mop, idx_to_kaddr(queue, pending_idx),
@@ -838,6 +843,7 @@ static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue,
 
 	memcpy(&queue->pending_tx_info[pending_idx].req, txp,
 	       sizeof(*txp));
+	queue->pending_tx_info[pending_idx].extra_count = extra_count;
 }
 
 static inline struct sk_buff *xenvif_alloc_skb(unsigned int size)
@@ -880,7 +886,7 @@ static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif_queue *que
 	     shinfo->nr_frags++, txp++, gop++) {
 		index = pending_index(queue->pending_cons++);
 		pending_idx = queue->pending_ring[index];
-		xenvif_tx_create_map_op(queue, pending_idx, txp, gop);
+		xenvif_tx_create_map_op(queue, pending_idx, txp, 0, gop);
 		frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx);
 	}
 
@@ -893,7 +899,8 @@ static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif_queue *que
 		     shinfo->nr_frags++, txp++, gop++) {
 			index = pending_index(queue->pending_cons++);
 			pending_idx = queue->pending_ring[index];
-			xenvif_tx_create_map_op(queue, pending_idx, txp, gop);
+			xenvif_tx_create_map_op(queue, pending_idx, txp, 0,
+						gop);
 			frag_set_pending_idx(&frags[shinfo->nr_frags],
 					     pending_idx);
 		}
@@ -1095,8 +1102,9 @@ static void xenvif_fill_frags(struct xenvif_queue *queue, struct sk_buff *skb)
 }
 
 static int xenvif_get_extras(struct xenvif_queue *queue,
-				struct xen_netif_extra_info *extras,
-				int work_to_do)
+			     struct xen_netif_extra_info *extras,
+			     unsigned int *extra_count,
+			     int work_to_do)
 {
 	struct xen_netif_extra_info extra;
 	RING_IDX cons = queue->tx.req_cons;
@@ -1109,9 +1117,12 @@ static int xenvif_get_extras(struct xenvif_queue *queue,
 		}
 
 		RING_COPY_REQUEST(&queue->tx, cons, &extra);
+
+		queue->tx.req_cons = ++cons;
+		(*extra_count)++;
+
 		if (unlikely(!extra.type ||
 			     extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
-			queue->tx.req_cons = ++cons;
 			netdev_err(queue->vif->dev,
 				   "Invalid extra type: %d\n", extra.type);
 			xenvif_fatal_tx_err(queue->vif);
@@ -1119,7 +1130,6 @@ static int xenvif_get_extras(struct xenvif_queue *queue,
 		}
 
 		memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
-		queue->tx.req_cons = ++cons;
 	} while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
 
 	return work_to_do;
@@ -1294,6 +1304,7 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
 		struct xen_netif_tx_request txreq;
 		struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
 		struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
+		unsigned int extra_count;
 		u16 pending_idx;
 		RING_IDX idx;
 		int work_to_do;
@@ -1330,8 +1341,10 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
 		queue->tx.req_cons = ++idx;
 
 		memset(extras, 0, sizeof(extras));
+		extra_count = 0;
 		if (txreq.flags & XEN_NETTXF_extra_info) {
 			work_to_do = xenvif_get_extras(queue, extras,
+						       &extra_count,
 						       work_to_do);
 			idx = queue->tx.req_cons;
 			if (unlikely(work_to_do < 0))
@@ -1344,7 +1357,7 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
 			extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1];
 			ret = xenvif_mcast_add(queue->vif, extra->u.mcast.addr);
 
-			make_tx_response(queue, &txreq,
+			make_tx_response(queue, &txreq, extra_count,
 					 (ret == 0) ?
 					 XEN_NETIF_RSP_OKAY :
 					 XEN_NETIF_RSP_ERROR);
@@ -1358,12 +1371,14 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
 			extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1];
 			xenvif_mcast_del(queue->vif, extra->u.mcast.addr);
 
-			make_tx_response(queue, &txreq, XEN_NETIF_RSP_OKAY);
+			make_tx_response(queue, &txreq, extra_count,
+					 XEN_NETIF_RSP_OKAY);
 			push_tx_responses(queue);
 			continue;
 		}
 
-		ret = xenvif_count_requests(queue, &txreq, txfrags, work_to_do);
+		ret = xenvif_count_requests(queue, &txreq, extra_count,
+					    txfrags, work_to_do);
 		if (unlikely(ret < 0))
 			break;
 
@@ -1372,7 +1387,7 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
 		if (unlikely(txreq.size < ETH_HLEN)) {
 			netdev_dbg(queue->vif->dev,
 				   "Bad packet size: %d\n", txreq.size);
-			xenvif_tx_err(queue, &txreq, idx);
+			xenvif_tx_err(queue, &txreq, extra_count, idx);
 			break;
 		}
 
@@ -1397,7 +1412,7 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
 		if (unlikely(skb == NULL)) {
 			netdev_dbg(queue->vif->dev,
 				   "Can't allocate a skb in start_xmit.\n");
-			xenvif_tx_err(queue, &txreq, idx);
+			xenvif_tx_err(queue, &txreq, extra_count, idx);
 			break;
 		}
 
@@ -1416,7 +1431,7 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
 			nskb = xenvif_alloc_skb(0);
 			if (unlikely(nskb == NULL)) {
 				kfree_skb(skb);
-				xenvif_tx_err(queue, &txreq, idx);
+				xenvif_tx_err(queue, &txreq, extra_count, idx);
 				if (net_ratelimit())
 					netdev_err(queue->vif->dev,
 						   "Can't allocate the frag_list skb.\n");
@@ -1457,13 +1472,16 @@ static void xenvif_tx_build_gops(struct xenvif_queue *queue,
 		if (data_len < txreq.size) {
 			frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
 					     pending_idx);
-			xenvif_tx_create_map_op(queue, pending_idx, &txreq, gop);
+			xenvif_tx_create_map_op(queue, pending_idx, &txreq,
+						extra_count, gop);
 			gop++;
 		} else {
 			frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
 					     INVALID_PENDING_IDX);
-			memcpy(&queue->pending_tx_info[pending_idx].req, &txreq,
-			       sizeof(txreq));
+			memcpy(&queue->pending_tx_info[pending_idx].req,
+			       &txreq, sizeof(txreq));
+			queue->pending_tx_info[pending_idx].extra_count =
+				extra_count;
 		}
 
 		queue->pending_cons++;
@@ -1804,7 +1822,8 @@ static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
 
 	spin_lock_irqsave(&queue->response_lock, flags);
 
-	make_tx_response(queue, &pending_tx_info->req, status);
+	make_tx_response(queue, &pending_tx_info->req,
+			 pending_tx_info->extra_count, status);
 
 	/* Release the pending index before pusing the Tx response so
 	 * its available before a new Tx request is pushed by the
@@ -1821,6 +1840,7 @@ static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
 
 static void make_tx_response(struct xenvif_queue *queue,
 			     struct xen_netif_tx_request *txp,
+			     unsigned int extra_count,
 			     s8       st)
 {
 	RING_IDX i = queue->tx.rsp_prod_pvt;
@@ -1830,7 +1850,7 @@ static void make_tx_response(struct xenvif_queue *queue,
 	resp->id     = txp->id;
 	resp->status = st;
 
-	if (txp->flags & XEN_NETTXF_extra_info)
+	while (extra_count-- != 0)
 		RING_GET_RESPONSE(&queue->tx, ++i)->status = XEN_NETIF_RSP_NULL;
 
 	queue->tx.rsp_prod_pvt = ++i;
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index 56ebd8267..bd182cd55 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -327,7 +327,7 @@ static int netback_probe(struct xenbus_device *dev,
 			goto abort_transaction;
 		}
 
-		/* We support multicast-control. */
+		/* We support dynamic multicast-control. */
 		err = xenbus_printf(xbt, dev->nodename,
 				    "feature-multicast-control", "%d", 1);
 		if (err) {
@@ -335,6 +335,14 @@ static int netback_probe(struct xenbus_device *dev,
 			goto abort_transaction;
 		}
 
+		err = xenbus_printf(xbt, dev->nodename,
+				    "feature-dynamic-multicast-control",
+				    "%d", 1);
+		if (err) {
+			message = "writing feature-dynamic-multicast-control";
+			goto abort_transaction;
+		}
+
 		err = xenbus_transaction_end(xbt, 0);
 	} while (err == -EAGAIN);
 
@@ -503,8 +511,6 @@ static void set_backend_state(struct backend_info *be,
 			switch (state) {
 			case XenbusStateInitWait:
 			case XenbusStateConnected:
-				pr_info("%s: prepare for reconnect\n",
-					be->dev->nodename);
 				backend_switch_state(be, XenbusStateInitWait);
 				break;
 			case XenbusStateClosing:
@@ -683,7 +689,8 @@ static void xen_net_rate_changed(struct xenbus_watch *watch,
 	}
 }
 
-static int xen_register_watchers(struct xenbus_device *dev, struct xenvif *vif)
+static int xen_register_credit_watch(struct xenbus_device *dev,
+				     struct xenvif *vif)
 {
 	int err = 0;
 	char *node;
@@ -708,7 +715,7 @@ static int xen_register_watchers(struct xenbus_device *dev, struct xenvif *vif)
 	return err;
 }
 
-static void xen_unregister_watchers(struct xenvif *vif)
+static void xen_unregister_credit_watch(struct xenvif *vif)
 {
 	if (vif->credit_watch.node) {
 		unregister_xenbus_watch(&vif->credit_watch);
@@ -717,6 +724,75 @@ static void xen_unregister_watchers(struct xenvif *vif)
 	}
 }
 
+static void xen_mcast_ctrl_changed(struct xenbus_watch *watch,
+				   const char **vec, unsigned int len)
+{
+	struct xenvif *vif = container_of(watch, struct xenvif,
+					  mcast_ctrl_watch);
+	struct xenbus_device *dev = xenvif_to_xenbus_device(vif);
+	int val;
+
+	if (xenbus_scanf(XBT_NIL, dev->otherend,
+			 "request-multicast-control", "%d", &val) < 0)
+		val = 0;
+	vif->multicast_control = !!val;
+}
+
+static int xen_register_mcast_ctrl_watch(struct xenbus_device *dev,
+					 struct xenvif *vif)
+{
+	int err = 0;
+	char *node;
+	unsigned maxlen = strlen(dev->otherend) +
+		sizeof("/request-multicast-control");
+
+	if (vif->mcast_ctrl_watch.node) {
+		pr_err_ratelimited("Watch is already registered\n");
+		return -EADDRINUSE;
+	}
+
+	node = kmalloc(maxlen, GFP_KERNEL);
+	if (!node) {
+		pr_err("Failed to allocate memory for watch\n");
+		return -ENOMEM;
+	}
+	snprintf(node, maxlen, "%s/request-multicast-control",
+		 dev->otherend);
+	vif->mcast_ctrl_watch.node = node;
+	vif->mcast_ctrl_watch.callback = xen_mcast_ctrl_changed;
+	err = register_xenbus_watch(&vif->mcast_ctrl_watch);
+	if (err) {
+		pr_err("Failed to set watcher %s\n",
+		       vif->mcast_ctrl_watch.node);
+		kfree(node);
+		vif->mcast_ctrl_watch.node = NULL;
+		vif->mcast_ctrl_watch.callback = NULL;
+	}
+	return err;
+}
+
+static void xen_unregister_mcast_ctrl_watch(struct xenvif *vif)
+{
+	if (vif->mcast_ctrl_watch.node) {
+		unregister_xenbus_watch(&vif->mcast_ctrl_watch);
+		kfree(vif->mcast_ctrl_watch.node);
+		vif->mcast_ctrl_watch.node = NULL;
+	}
+}
+
+static void xen_register_watchers(struct xenbus_device *dev,
+				  struct xenvif *vif)
+{
+	xen_register_credit_watch(dev, vif);
+	xen_register_mcast_ctrl_watch(dev, vif);
+}
+
+static void xen_unregister_watchers(struct xenvif *vif)
+{
+	xen_unregister_mcast_ctrl_watch(vif);
+	xen_unregister_credit_watch(vif);
+}
+
 static void unregister_hotplug_status_watch(struct backend_info *be)
 {
 	if (be->have_hotplug_status_watch) {
@@ -1030,11 +1106,6 @@ static int read_xenbus_vif_flags(struct backend_info *be)
 		val = 0;
 	vif->ipv6_csum = !!val;
 
-	if (xenbus_scanf(XBT_NIL, dev->otherend, "request-multicast-control",
-			 "%d", &val) < 0)
-		val = 0;
-	vif->multicast_control = !!val;
-
 	return 0;
 }