[PATCH 1/3] net/hyperv: Remove unnecessary kmap_atomic in netvsc driver

@@ -39,9 +39,6 @@ struct xferpage_packet {
 	u32 count;
 };
 
-/* The number of pages which are enough to cover jumbo frame buffer. */
-#define NETVSC_PACKET_MAXPAGE		4
-
 /*
  * Represent netvsc packet which contains 1 RNDIS and 1 ethernet frame
  * within the RNDIS

@@ -77,8 +74,9 @@ struct hv_netvsc_packet {
 
 	u32 total_data_buflen;
 	/* Points to the send/receive buffer where the ethernet frame is */
+	void *data;
 	u32 page_buf_cnt;
-	struct hv_page_buffer page_buf[NETVSC_PACKET_MAXPAGE];
+	struct hv_page_buffer page_buf[0];
 };
 
 struct netvsc_device_info {

@@ -603,12 +603,10 @@ static void netvsc_receive(struct hv_device *device,
 	struct vmtransfer_page_packet_header *vmxferpage_packet;
 	struct nvsp_message *nvsp_packet;
 	struct hv_netvsc_packet *netvsc_packet = NULL;
-	unsigned long start;
-	unsigned long end, end_virtual;
 	/* struct netvsc_driver *netvscDriver; */
 	struct xferpage_packet *xferpage_packet = NULL;
-	int i, j;
-	int count = 0, bytes_remain = 0;
+	int i;
+	int count = 0;
 	unsigned long flags;
 	struct net_device *ndev;
 

@@ -717,53 +715,10 @@ static void netvsc_receive(struct hv_device *device,
 		netvsc_packet->completion.recv.recv_completion_tid =
 					vmxferpage_packet->d.trans_id;
 
+		netvsc_packet->data = (void *)((unsigned long)net_device->
+			recv_buf + vmxferpage_packet->ranges[i].byte_offset);
 		netvsc_packet->total_data_buflen =
 					vmxferpage_packet->ranges[i].byte_count;
-		netvsc_packet->page_buf_cnt = 1;
-
-		netvsc_packet->page_buf[0].len =
-					vmxferpage_packet->ranges[i].byte_count;
-
-		start = virt_to_phys((void *)((unsigned long)net_device->
-		recv_buf + vmxferpage_packet->ranges[i].byte_offset));
-
-		netvsc_packet->page_buf[0].pfn = start >> PAGE_SHIFT;
-		end_virtual = (unsigned long)net_device->recv_buf
-		    + vmxferpage_packet->ranges[i].byte_offset
-		    + vmxferpage_packet->ranges[i].byte_count - 1;
-		end = virt_to_phys((void *)end_virtual);
-
-		/* Calculate the page relative offset */
-		netvsc_packet->page_buf[0].offset =
-			vmxferpage_packet->ranges[i].byte_offset &
-			(PAGE_SIZE - 1);
-		if ((end >> PAGE_SHIFT) != (start >> PAGE_SHIFT)) {
-			/* Handle frame across multiple pages: */
-			netvsc_packet->page_buf[0].len =
-				(netvsc_packet->page_buf[0].pfn <<
-				 PAGE_SHIFT)
-				+ PAGE_SIZE - start;
-			bytes_remain = netvsc_packet->total_data_buflen -
-					netvsc_packet->page_buf[0].len;
-			for (j = 1; j < NETVSC_PACKET_MAXPAGE; j++) {
-				netvsc_packet->page_buf[j].offset = 0;
-				if (bytes_remain <= PAGE_SIZE) {
-					netvsc_packet->page_buf[j].len =
-						bytes_remain;
-					bytes_remain = 0;
-				} else {
-					netvsc_packet->page_buf[j].len =
-						PAGE_SIZE;
-					bytes_remain -= PAGE_SIZE;
-				}
-				netvsc_packet->page_buf[j].pfn =
-				    virt_to_phys((void *)(end_virtual -
-						bytes_remain)) >> PAGE_SHIFT;
-				netvsc_packet->page_buf_cnt++;
-				if (bytes_remain == 0)
-					break;
-			}
-		}
 
 		/* Pass it to the upper layer */
 		rndis_filter_receive(device, netvsc_packet);

@@ -251,9 +251,6 @@ int netvsc_recv_callback(struct hv_device *device_obj,
 {
 	struct net_device *net = dev_get_drvdata(&device_obj->device);
 	struct sk_buff *skb;
-	void *data;
-	int i;
-	unsigned long flags;
 	struct netvsc_device *net_device;
 
 	net_device = hv_get_drvdata(device_obj);

@@ -272,27 +269,12 @@ int netvsc_recv_callback(struct hv_device *device_obj,
 		return 0;
 	}
 
-	/* for kmap_atomic */
-	local_irq_save(flags);
-
 	/*
 	 * Copy to skb. This copy is needed here since the memory pointed by
 	 * hv_netvsc_packet cannot be deallocated
 	 */
-	for (i = 0; i < packet->page_buf_cnt; i++) {
-		data = kmap_atomic(pfn_to_page(packet->page_buf[i].pfn),
-					       KM_IRQ1);
-		data = (void *)(unsigned long)data +
-				packet->page_buf[i].offset;
-
-		memcpy(skb_put(skb, packet->page_buf[i].len), data,
-		       packet->page_buf[i].len);
-
-		kunmap_atomic((void *)((unsigned long)data -
-				       packet->page_buf[i].offset), KM_IRQ1);
-	}
-
-	local_irq_restore(flags);
+	memcpy(skb_put(skb, packet->total_data_buflen), packet->data,
+		packet->total_data_buflen);
 
 	skb->protocol = eth_type_trans(skb, net);
 	skb->ip_summed = CHECKSUM_NONE;

@@ -309,7 +309,6 @@ static void rndis_filter_receive_data(struct rndis_device *dev,
 {
 	struct rndis_packet *rndis_pkt;
 	u32 data_offset;
-	int i;
 
 	rndis_pkt = &msg->msg.pkt;
 

@@ -322,17 +321,7 @@ static void rndis_filter_receive_data(struct rndis_device *dev,
 	data_offset = RNDIS_HEADER_SIZE + rndis_pkt->data_offset;
 
 	pkt->total_data_buflen -= data_offset;
-	pkt->page_buf[0].offset += data_offset;
-	pkt->page_buf[0].len -= data_offset;
-
-	/* Drop the 0th page, if rndis data go beyond page boundary */
-	if (pkt->page_buf[0].offset >= PAGE_SIZE) {
-		pkt->page_buf[1].offset = pkt->page_buf[0].offset - PAGE_SIZE;
-		pkt->page_buf[1].len -= pkt->page_buf[1].offset;
-		pkt->page_buf_cnt--;
-		for (i = 0; i < pkt->page_buf_cnt; i++)
-			pkt->page_buf[i] = pkt->page_buf[i+1];
-	}
+	pkt->data = (void *)((unsigned long)pkt->data + data_offset);
 
 	pkt->is_data_pkt = true;
 

@@ -367,11 +356,7 @@ int rndis_filter_receive(struct hv_device *dev,
 		return -ENODEV;
 	}
 
-	rndis_hdr = (struct rndis_message *)kmap_atomic(
-			pfn_to_page(pkt->page_buf[0].pfn), KM_IRQ0);
-
-	rndis_hdr = (void *)((unsigned long)rndis_hdr +
-			pkt->page_buf[0].offset);
+	rndis_hdr = pkt->data;
 
 	/* Make sure we got a valid rndis message */
 	if ((rndis_hdr->ndis_msg_type != REMOTE_NDIS_PACKET_MSG) &&

@@ -387,8 +372,6 @@ int rndis_filter_receive(struct hv_device *dev,
 			sizeof(struct rndis_message) :
 			rndis_hdr->msg_len);
 
-	kunmap_atomic(rndis_hdr - pkt->page_buf[0].offset, KM_IRQ0);
-
 	dump_rndis_message(dev, &rndis_msg);
 
 	switch (rndis_msg.ndis_msg_type) {

@@ -134,8 +134,7 @@ int rndis_filter_set_packet_filter(struct rndis_device *dev, u32 new_filter);
 #define NVSP_INVALID_PROTOCOL_VERSION	((u32)0xFFFFFFFF)
 
 #define NVSP_PROTOCOL_VERSION_1		2
-#define NVSP_MIN_PROTOCOL_VERSION	NVSP_PROTOCOL_VERSION_1
-#define NVSP_MAX_PROTOCOL_VERSION	NVSP_PROTOCOL_VERSION_1
+#define NVSP_PROTOCOL_VERSION_2		0x30002
 
 enum {
 	NVSP_MSG_TYPE_NONE = 0,

@@ -160,11 +159,36 @@ enum {
 	NVSP_MSG1_TYPE_SEND_RNDIS_PKT,
 	NVSP_MSG1_TYPE_SEND_RNDIS_PKT_COMPLETE,
 
-	/*
-	 * This should be set to the number of messages for the version with
-	 * the maximum number of messages.
-	 */
-	NVSP_NUM_MSG_PER_VERSION		= 9,
+	/* Version 2 messages */
+	NVSP_MSG2_TYPE_SEND_CHIMNEY_DELEGATED_BUF,
+	NVSP_MSG2_TYPE_SEND_CHIMNEY_DELEGATED_BUF_COMP,
+	NVSP_MSG2_TYPE_REVOKE_CHIMNEY_DELEGATED_BUF,
+
+	NVSP_MSG2_TYPE_RESUME_CHIMNEY_RX_INDICATION,
+
+	NVSP_MSG2_TYPE_TERMINATE_CHIMNEY,
+	NVSP_MSG2_TYPE_TERMINATE_CHIMNEY_COMP,
+
+	NVSP_MSG2_TYPE_INDICATE_CHIMNEY_EVENT,
+
+	NVSP_MSG2_TYPE_SEND_CHIMNEY_PKT,
+	NVSP_MSG2_TYPE_SEND_CHIMNEY_PKT_COMP,
+
+	NVSP_MSG2_TYPE_POST_CHIMNEY_RECV_REQ,
+	NVSP_MSG2_TYPE_POST_CHIMNEY_RECV_REQ_COMP,
+
+	NVSP_MSG2_TYPE_ALLOC_RXBUF,
+	NVSP_MSG2_TYPE_ALLOC_RXBUF_COMP,
+
+	NVSP_MSG2_TYPE_FREE_RXBUF,
+
+	NVSP_MSG2_TYPE_SEND_VMQ_RNDIS_PKT,
+	NVSP_MSG2_TYPE_SEND_VMQ_RNDIS_PKT_COMP,
+
+	NVSP_MSG2_TYPE_SEND_NDIS_CONFIG,
+
+	NVSP_MSG2_TYPE_ALLOC_CHIMNEY_HANDLE,
+	NVSP_MSG2_TYPE_ALLOC_CHIMNEY_HANDLE_COMP,
 };
 
 enum {

@@ -175,6 +199,7 @@ enum {
 	NVSP_STAT_PROTOCOL_TOO_OLD,
 	NVSP_STAT_INVALID_RNDIS_PKT,
 	NVSP_STAT_BUSY,
+	NVSP_STAT_PROTOCOL_UNSUPPORTED,
 	NVSP_STAT_MAX,
 };
 

@@ -359,9 +384,69 @@ union nvsp_1_message_uber {
 						send_rndis_pkt_complete;
 } __packed;
 
+
+/*
+ * Network VSP protocol version 2 messages:
+ */
+struct nvsp_2_vsc_capability {
+	union {
+		u64 data;
+		struct {
+			u64 vmq:1;
+			u64 chimney:1;
+			u64 sriov:1;
+			u64 ieee8021q:1;
+			u64 correlation_id:1;
+		};
+	};
+} __packed;
+
+struct nvsp_2_send_ndis_config {
+	u32 mtu;
+	u32 reserved;
+	struct nvsp_2_vsc_capability capability;
+} __packed;
+
+/* Allocate receive buffer */
+struct nvsp_2_alloc_rxbuf {
+	/* Allocation ID to match the allocation request and response */
+	u32 alloc_id;
+
+	/* Length of the VM shared memory receive buffer that needs to
+	 * be allocated
+	 */
+	u32 len;
+} __packed;
+
+/* Allocate receive buffer complete */
+struct nvsp_2_alloc_rxbuf_comp {
+	/* The NDIS_STATUS code for buffer allocation */
+	u32 status;
+
+	u32 alloc_id;
+
+	/* GPADL handle for the allocated receive buffer */
+	u32 gpadl_handle;
+
+	/* Receive buffer ID */
+	u64 recv_buf_id;
+} __packed;
+
+struct nvsp_2_free_rxbuf {
+	u64 recv_buf_id;
+} __packed;
+
+union nvsp_2_message_uber {
+	struct nvsp_2_send_ndis_config send_ndis_config;
+	struct nvsp_2_alloc_rxbuf alloc_rxbuf;
+	struct nvsp_2_alloc_rxbuf_comp alloc_rxbuf_comp;
+	struct nvsp_2_free_rxbuf free_rxbuf;
+} __packed;
+
 union nvsp_all_messages {
 	union nvsp_message_init_uber init_msg;
 	union nvsp_1_message_uber v1_msg;
+	union nvsp_2_message_uber v2_msg;
 } __packed;
 
 /* ALL Messages */

@@ -391,6 +476,8 @@ struct nvsp_message {
 struct netvsc_device {
 	struct hv_device *dev;
 
+	u32 nvsp_version;
+
 	atomic_t num_outstanding_sends;
 	bool destroy;
 	/*

@@ -28,6 +28,7 @@
 #include <linux/io.h>
 #include <linux/slab.h>
 #include <linux/netdevice.h>
+#include <linux/if_ether.h>
 
 #include "hyperv_net.h"
 

@@ -260,27 +261,18 @@ exit:
 }
 
 
-static int netvsc_connect_vsp(struct hv_device *device)
+/* Negotiate NVSP protocol version */
+static int negotiate_nvsp_ver(struct hv_device *device,
+			      struct netvsc_device *net_device,
+			      struct nvsp_message *init_packet,
+			      u32 nvsp_ver)
 {
 	int ret, t;
-	struct netvsc_device *net_device;
-	struct nvsp_message *init_packet;
-	int ndis_version;
-	struct net_device *ndev;
-
-	net_device = get_outbound_net_device(device);
-	if (!net_device)
-		return -ENODEV;
-	ndev = net_device->ndev;
-
-	init_packet = &net_device->channel_init_pkt;
 
 	memset(init_packet, 0, sizeof(struct nvsp_message));
 	init_packet->hdr.msg_type = NVSP_MSG_TYPE_INIT;
-	init_packet->msg.init_msg.init.min_protocol_ver =
-		NVSP_MIN_PROTOCOL_VERSION;
-	init_packet->msg.init_msg.init.max_protocol_ver =
-		NVSP_MAX_PROTOCOL_VERSION;
+	init_packet->msg.init_msg.init.min_protocol_ver = nvsp_ver;
+	init_packet->msg.init_msg.init.max_protocol_ver = nvsp_ver;
 
 	/* Send the init request */
 	ret = vmbus_sendpacket(device->channel, init_packet,

@@ -290,26 +282,62 @@ static int netvsc_connect_vsp(struct hv_device *device)
 			       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 
 	if (ret != 0)
-		goto cleanup;
+		return ret;
 
 	t = wait_for_completion_timeout(&net_device->channel_init_wait, 5*HZ);
 
-	if (t == 0) {
-		ret = -ETIMEDOUT;
-		goto cleanup;
-	}
+	if (t == 0)
+		return -ETIMEDOUT;
 
 	if (init_packet->msg.init_msg.init_complete.status !=
-	    NVSP_STAT_SUCCESS) {
-		ret = -EINVAL;
-		goto cleanup;
-	}
+	    NVSP_STAT_SUCCESS)
+		return -EINVAL;
 
-	if (init_packet->msg.init_msg.init_complete.
-	    negotiated_protocol_ver != NVSP_PROTOCOL_VERSION_1) {
+	if (nvsp_ver != NVSP_PROTOCOL_VERSION_2)
+		return 0;
+
+	/* NVSPv2 only: Send NDIS config */
+	memset(init_packet, 0, sizeof(struct nvsp_message));
+	init_packet->hdr.msg_type = NVSP_MSG2_TYPE_SEND_NDIS_CONFIG;
+	init_packet->msg.v2_msg.send_ndis_config.mtu = ETH_DATA_LEN;
+
+	ret = vmbus_sendpacket(device->channel, init_packet,
+				sizeof(struct nvsp_message),
+				(unsigned long)init_packet,
+				VM_PKT_DATA_INBAND, 0);
+
+	return ret;
+}
+
+static int netvsc_connect_vsp(struct hv_device *device)
+{
+	int ret;
+	struct netvsc_device *net_device;
+	struct nvsp_message *init_packet;
+	int ndis_version;
+	struct net_device *ndev;
+
+	net_device = get_outbound_net_device(device);
+	if (!net_device)
+		return -ENODEV;
+	ndev = net_device->ndev;
+
+	init_packet = &net_device->channel_init_pkt;
+
+	/* Negotiate the latest NVSP protocol supported */
+	if (negotiate_nvsp_ver(device, net_device, init_packet,
+			       NVSP_PROTOCOL_VERSION_2) == 0) {
+		net_device->nvsp_version = NVSP_PROTOCOL_VERSION_2;
+	} else if (negotiate_nvsp_ver(device, net_device, init_packet,
+				    NVSP_PROTOCOL_VERSION_1) == 0) {
+		net_device->nvsp_version = NVSP_PROTOCOL_VERSION_1;
+	} else {
 		ret = -EPROTO;
 		goto cleanup;
 	}
+
+	pr_debug("Negotiated NVSP version:%x\n", net_device->nvsp_version);
+
 	/* Send the ndis version */
 	memset(init_packet, 0, sizeof(struct nvsp_message));
 

@@ -456,12 +456,9 @@ struct nvsp_message {
 } __packed;
 
 
+#define NETVSC_MTU 65536
 
-
-/* #define NVSC_MIN_PROTOCOL_VERSION		1 */
-/* #define NVSC_MAX_PROTOCOL_VERSION		1 */
-
-#define NETVSC_RECEIVE_BUFFER_SIZE		(1024*1024)	/* 1MB */
+#define NETVSC_RECEIVE_BUFFER_SIZE		(1024*1024*2)	/* 2MB */
 
 #define NETVSC_RECEIVE_BUFFER_ID		0xcafe
 

@@ -479,6 +476,7 @@ struct netvsc_device {
 	u32 nvsp_version;
 
 	atomic_t num_outstanding_sends;
+	bool start_remove;
 	bool destroy;
 	/*
 	 * List of free preallocated hv_netvsc_packet to represent receive

@@ -42,7 +42,7 @@ static struct netvsc_device *alloc_net_device(struct hv_device *device)
 	if (!net_device)
 		return NULL;
 
-
+	net_device->start_remove = false;
 	net_device->destroy = false;
 	net_device->dev = device;
 	net_device->ndev = ndev;

@@ -299,7 +299,7 @@ static int negotiate_nvsp_ver(struct hv_device *device,
 	/* NVSPv2 only: Send NDIS config */
 	memset(init_packet, 0, sizeof(struct nvsp_message));
 	init_packet->hdr.msg_type = NVSP_MSG2_TYPE_SEND_NDIS_CONFIG;
-	init_packet->msg.v2_msg.send_ndis_config.mtu = ETH_DATA_LEN;
+	init_packet->msg.v2_msg.send_ndis_config.mtu = net_device->ndev->mtu;
 
 	ret = vmbus_sendpacket(device->channel, init_packet,
 				sizeof(struct nvsp_message),

@@ -464,7 +464,7 @@ static void netvsc_send_completion(struct hv_device *device,
 
 		atomic_dec(&net_device->num_outstanding_sends);
 
-		if (netif_queue_stopped(ndev))
+		if (netif_queue_stopped(ndev) && !net_device->start_remove)
 			netif_wake_queue(ndev);
 	} else {
 		netdev_err(ndev, "Unknown send completion packet type- "

@@ -148,10 +148,12 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
 	struct net_device_context *net_device_ctx = netdev_priv(net);
 	struct hv_netvsc_packet *packet;
 	int ret;
-	unsigned int i, num_pages;
+	unsigned int i, num_pages, npg_data;
 
-	/* Add 1 for skb->data and additional one for RNDIS */
-	num_pages = skb_shinfo(skb)->nr_frags + 1 + 1;
+	/* Add multipage for skb->data and additional one for RNDIS */
+	npg_data = (((unsigned long)skb->data + skb_headlen(skb) - 1)
+		>> PAGE_SHIFT) - ((unsigned long)skb->data >> PAGE_SHIFT) + 1;
+	num_pages = skb_shinfo(skb)->nr_frags + npg_data + 1;
 
 	/* Allocate a netvsc packet based on # of frags. */
 	packet = kzalloc(sizeof(struct hv_netvsc_packet) +

@@ -174,21 +176,36 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
 	packet->page_buf_cnt = num_pages;
 
 	/* Initialize it from the skb */
-	packet->total_data_buflen	= skb->len;
+	packet->total_data_buflen = skb->len;
 
 	/* Start filling in the page buffers starting after RNDIS buffer. */
 	packet->page_buf[1].pfn = virt_to_phys(skb->data) >> PAGE_SHIFT;
 	packet->page_buf[1].offset
 		= (unsigned long)skb->data & (PAGE_SIZE - 1);
-	packet->page_buf[1].len = skb_headlen(skb);
+	if (npg_data == 1)
+		packet->page_buf[1].len = skb_headlen(skb);
+	else
+		packet->page_buf[1].len = PAGE_SIZE
+			- packet->page_buf[1].offset;
+
+	for (i = 2; i <= npg_data; i++) {
+		packet->page_buf[i].pfn = virt_to_phys(skb->data
+			+ PAGE_SIZE * (i-1)) >> PAGE_SHIFT;
+		packet->page_buf[i].offset = 0;
+		packet->page_buf[i].len = PAGE_SIZE;
+	}
+	if (npg_data > 1)
+		packet->page_buf[npg_data].len = (((unsigned long)skb->data
+			+ skb_headlen(skb) - 1) & (PAGE_SIZE - 1)) + 1;
 
 	/* Additional fragments are after SKB data */
 	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
 		const skb_frag_t *f = &skb_shinfo(skb)->frags[i];
 
-		packet->page_buf[i+2].pfn = page_to_pfn(skb_frag_page(f));
-		packet->page_buf[i+2].offset = f->page_offset;
-		packet->page_buf[i+2].len = skb_frag_size(f);
+		packet->page_buf[i+npg_data+1].pfn =
+			page_to_pfn(skb_frag_page(f));
+		packet->page_buf[i+npg_data+1].offset = f->page_offset;
+		packet->page_buf[i+npg_data+1].len = skb_frag_size(f);
 	}
 
 	/* Set the completion routine */

@@ -300,6 +317,39 @@ static void netvsc_get_drvinfo(struct net_device *net,
 	strcpy(info->fw_version, "N/A");
 }
 
+static int netvsc_change_mtu(struct net_device *ndev, int mtu)
+{
+	struct net_device_context *ndevctx = netdev_priv(ndev);
+	struct hv_device *hdev =  ndevctx->device_ctx;
+	struct netvsc_device *nvdev = hv_get_drvdata(hdev);
+	struct netvsc_device_info device_info;
+	int limit = ETH_DATA_LEN;
+
+	if (nvdev == NULL || nvdev->destroy)
+		return -ENODEV;
+
+	if (nvdev->nvsp_version == NVSP_PROTOCOL_VERSION_2)
+		limit = NETVSC_MTU;
+
+	if (mtu < 68 || mtu > limit)
+		return -EINVAL;
+
+	nvdev->start_remove = true;
+	cancel_delayed_work_sync(&ndevctx->dwork);
+	netif_stop_queue(ndev);
+	rndis_filter_device_remove(hdev);
+
+	ndev->mtu = mtu;
+
+	ndevctx->device_ctx = hdev;
+	hv_set_drvdata(hdev, ndev);
+	device_info.ring_size = ring_size;
+	rndis_filter_device_add(hdev, &device_info);
+	netif_wake_queue(ndev);
+
+	return 0;
+}
+
 static const struct ethtool_ops ethtool_ops = {
 	.get_drvinfo	= netvsc_get_drvinfo,
 	.get_link	= ethtool_op_get_link,

@@ -310,7 +360,7 @@ static const struct net_device_ops device_ops = {
 	.ndo_stop =			netvsc_close,
 	.ndo_start_xmit =		netvsc_start_xmit,
 	.ndo_set_rx_mode =		netvsc_set_multicast_list,
-	.ndo_change_mtu =		eth_change_mtu,
+	.ndo_change_mtu =		netvsc_change_mtu,
 	.ndo_validate_addr =		eth_validate_addr,
 	.ndo_set_mac_address =		eth_mac_addr,
 };

@@ -403,6 +453,8 @@ static int netvsc_remove(struct hv_device *dev)
 		return 0;
 	}
 
+	net_device->start_remove = true;
+
 	ndev_ctx = netdev_priv(net);
 	cancel_delayed_work_sync(&ndev_ctx->dwork);
 

@@ -35,7 +35,7 @@
 #include <linux/mod_devicetable.h>
 
 
-#define MAX_PAGE_BUFFER_COUNT				16
+#define MAX_PAGE_BUFFER_COUNT				18
 #define MAX_MULTIPAGE_BUFFER_COUNT			32 /* 128K */
 
 #pragma pack(push, 1)