4 files changed, 46 insertions, 17 deletions

diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index d6c2558..12cc64b 100644
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -765,7 +765,8 @@ struct netvsc_device {
 	u32 max_chn;
 	u32 num_chn;
 
-	refcount_t sc_offered;
+	atomic_t open_chn;
+	wait_queue_head_t subchan_open;
 
 	struct rndis_device *extension;
 
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 0a9167d..d18c332 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -78,6 +78,7 @@ static struct netvsc_device *alloc_net_device(void)
 	net_device->max_pkt = RNDIS_MAX_PKT_DEFAULT;
 	net_device->pkt_align = RNDIS_PKT_ALIGN_DEFAULT;
 	init_completion(&net_device->channel_init_wait);
+	init_waitqueue_head(&net_device->subchan_open);
 
 	return net_device;
 }
@@ -1302,6 +1303,8 @@ int netvsc_device_add(struct hv_device *device,
 		struct netvsc_channel *nvchan = &net_device->chan_table[i];
 
 		nvchan->channel = device->channel;
+		u64_stats_init(&nvchan->tx_stats.syncp);
+		u64_stats_init(&nvchan->rx_stats.syncp);
 	}
 
 	/* Enable NAPI handler before init callbacks */
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 63c98bb..0d78727 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -315,14 +315,34 @@ static u32 init_page_array(void *hdr, u32 len, struct sk_buff *skb,
 	return slots_used;
 }
 
-/* Estimate number of page buffers neede to transmit
- * Need at most 2 for RNDIS header plus skb body and fragments.
- */
-static unsigned int netvsc_get_slots(const struct sk_buff *skb)
+static int count_skb_frag_slots(struct sk_buff *skb)
+{
+	int i, frags = skb_shinfo(skb)->nr_frags;
+	int pages = 0;
+
+	for (i = 0; i < frags; i++) {
+		skb_frag_t *frag = skb_shinfo(skb)->frags + i;
+		unsigned long size = skb_frag_size(frag);
+		unsigned long offset = frag->page_offset;
+
+		/* Skip unused frames from start of page */
+		offset &= ~PAGE_MASK;
+		pages += PFN_UP(offset + size);
+	}
+	return pages;
+}
+
+static int netvsc_get_slots(struct sk_buff *skb)
 {
-	return PFN_UP(offset_in_page(skb->data) + skb_headlen(skb))
-		+ skb_shinfo(skb)->nr_frags
-		+ 2;
+	char *data = skb->data;
+	unsigned int offset = offset_in_page(data);
+	unsigned int len = skb_headlen(skb);
+	int slots;
+	int frag_slots;
+
+	slots = DIV_ROUND_UP(offset + len, PAGE_SIZE);
+	frag_slots = count_skb_frag_slots(skb);
+	return slots + frag_slots;
 }
 
 static u32 net_checksum_info(struct sk_buff *skb)
@@ -360,18 +380,21 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
 	struct hv_page_buffer page_buf[MAX_PAGE_BUFFER_COUNT];
 	struct hv_page_buffer *pb = page_buf;
 
-	/* We can only transmit MAX_PAGE_BUFFER_COUNT number
+	/* We will atmost need two pages to describe the rndis
+	 * header. We can only transmit MAX_PAGE_BUFFER_COUNT number
 	 * of pages in a single packet. If skb is scattered around
 	 * more pages we try linearizing it.
 	 */
-	num_data_pgs = netvsc_get_slots(skb);
+
+	num_data_pgs = netvsc_get_slots(skb) + 2;
+
 	if (unlikely(num_data_pgs > MAX_PAGE_BUFFER_COUNT)) {
 		++net_device_ctx->eth_stats.tx_scattered;
 
 		if (skb_linearize(skb))
 			goto no_memory;
 
-		num_data_pgs = netvsc_get_slots(skb);
+		num_data_pgs = netvsc_get_slots(skb) + 2;
 		if (num_data_pgs > MAX_PAGE_BUFFER_COUNT) {
 			++net_device_ctx->eth_stats.tx_too_big;
 			goto drop;
diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c
index 85c00e1..d6308ff 100644
--- a/drivers/net/hyperv/rndis_filter.c
+++ b/drivers/net/hyperv/rndis_filter.c
@@ -1048,8 +1048,8 @@ static void netvsc_sc_open(struct vmbus_channel *new_sc)
 	else
 		netif_napi_del(&nvchan->napi);
 
-	if (refcount_dec_and_test(&nvscdev->sc_offered))
-		complete(&nvscdev->channel_init_wait);
+	atomic_inc(&nvscdev->open_chn);
+	wake_up(&nvscdev->subchan_open);
 }
 
 int rndis_filter_device_add(struct hv_device *dev,
@@ -1090,8 +1090,6 @@ int rndis_filter_device_add(struct hv_device *dev,
 	net_device->max_chn = 1;
 	net_device->num_chn = 1;
 
-	refcount_set(&net_device->sc_offered, 0);
-
 	net_device->extension = rndis_device;
 	rndis_device->ndev = net;
 
@@ -1221,11 +1219,11 @@ int rndis_filter_device_add(struct hv_device *dev,
 		rndis_device->ind_table[i] = ethtool_rxfh_indir_default(i,
 							net_device->num_chn);
 
+	atomic_set(&net_device->open_chn, 1);
 	num_rss_qs = net_device->num_chn - 1;
 	if (num_rss_qs == 0)
 		return 0;
 
-	refcount_set(&net_device->sc_offered, num_rss_qs);
 	vmbus_set_sc_create_callback(dev->channel, netvsc_sc_open);
 
 	init_packet = &net_device->channel_init_pkt;
@@ -1242,15 +1240,19 @@ int rndis_filter_device_add(struct hv_device *dev,
 	if (ret)
 		goto out;
 
+	wait_for_completion(&net_device->channel_init_wait);
 	if (init_packet->msg.v5_msg.subchn_comp.status != NVSP_STAT_SUCCESS) {
 		ret = -ENODEV;
 		goto out;
 	}
-	wait_for_completion(&net_device->channel_init_wait);
 
 	net_device->num_chn = 1 +
 		init_packet->msg.v5_msg.subchn_comp.num_subchannels;
 
+	/* wait for all sub channels to open */
+	wait_event(net_device->subchan_open,
+		   atomic_read(&net_device->open_chn) == net_device->num_chn);
+
 	/* ignore failues from setting rss parameters, still have channels */
 	rndis_filter_set_rss_param(rndis_device, netvsc_hash_key,
 				   net_device->num_chn);