netvsc: add rtnl annotations in rndis

[mirror_ubuntu-bionic-kernel.git] / drivers / net / hyperv / netvsc_drv.c

/*
 * Copyright (c) 2009, Microsoft Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, see <http://www.gnu.org/licenses/>.
 *
 * Authors:
 *   Haiyang Zhang <haiyangz@microsoft.com>
 *   Hank Janssen  <hjanssen@microsoft.com>
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/init.h>
#include <linux/atomic.h>
#include <linux/module.h>
#include <linux/highmem.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/delay.h>
#include <linux/netdevice.h>
#include <linux/inetdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/if_vlan.h>
#include <linux/in.h>
#include <linux/slab.h>
#include <net/arp.h>
#include <net/route.h>
#include <net/sock.h>
#include <net/pkt_sched.h>
#include <net/checksum.h>
#include <net/ip6_checksum.h>

#include "hyperv_net.h"

#define RING_SIZE_MIN 64
#define LINKCHANGE_INT (2 * HZ)

static int ring_size = 128;
module_param(ring_size, int, S_IRUGO);
MODULE_PARM_DESC(ring_size, "Ring buffer size (# of pages)");

static const u32 default_msg = NETIF_MSG_DRV | NETIF_MSG_PROBE |
                                NETIF_MSG_LINK | NETIF_MSG_IFUP |
                                NETIF_MSG_IFDOWN | NETIF_MSG_RX_ERR |
                                NETIF_MSG_TX_ERR;

static int debug = -1;
module_param(debug, int, S_IRUGO);
MODULE_PARM_DESC(debug, "Debug level (0=none,...,16=all)");

static void netvsc_set_multicast_list(struct net_device *net)
{
        struct net_device_context *net_device_ctx = netdev_priv(net);
        struct netvsc_device *nvdev = rtnl_dereference(net_device_ctx->nvdev);

        rndis_filter_update(nvdev);
}

static int netvsc_open(struct net_device *net)
{
        struct net_device_context *ndev_ctx = netdev_priv(net);
        struct netvsc_device *nvdev = rtnl_dereference(ndev_ctx->nvdev);
        struct rndis_device *rdev;
        int ret = 0;

        netif_carrier_off(net);

        /* Open up the device */
        ret = rndis_filter_open(nvdev);
        if (ret != 0) {
                netdev_err(net, "unable to open device (ret %d).\n", ret);
                return ret;
        }

        netif_tx_wake_all_queues(net);

        rdev = nvdev->extension;
        if (!rdev->link_state && !ndev_ctx->datapath)
                netif_carrier_on(net);

        return ret;
}

static int netvsc_close(struct net_device *net)
{
        struct net_device_context *net_device_ctx = netdev_priv(net);
        struct netvsc_device *nvdev = rtnl_dereference(net_device_ctx->nvdev);
        int ret;
        u32 aread, i, msec = 10, retry = 0, retry_max = 20;
        struct vmbus_channel *chn;

        netif_tx_disable(net);

        ret = rndis_filter_close(nvdev);
        if (ret != 0) {
                netdev_err(net, "unable to close device (ret %d).\n", ret);
                return ret;
        }

        /* Ensure pending bytes in ring are read */
        while (true) {
                aread = 0;
                for (i = 0; i < nvdev->num_chn; i++) {
                        chn = nvdev->chan_table[i].channel;
                        if (!chn)
                                continue;

                        aread = hv_get_bytes_to_read(&chn->inbound);
                        if (aread)
                                break;

                        aread = hv_get_bytes_to_read(&chn->outbound);
                        if (aread)
                                break;
                }

                retry++;
                if (retry > retry_max || aread == 0)
                        break;

                msleep(msec);

                if (msec < 1000)
                        msec *= 2;
        }

        if (aread) {
                netdev_err(net, "Ring buffer not empty after closing rndis\n");
                ret = -ETIMEDOUT;
        }

        return ret;
}

static void *init_ppi_data(struct rndis_message *msg, u32 ppi_size,
                                int pkt_type)
{
        struct rndis_packet *rndis_pkt;
        struct rndis_per_packet_info *ppi;

        rndis_pkt = &msg->msg.pkt;
        rndis_pkt->data_offset += ppi_size;

        ppi = (struct rndis_per_packet_info *)((void *)rndis_pkt +
                rndis_pkt->per_pkt_info_offset + rndis_pkt->per_pkt_info_len);

        ppi->size = ppi_size;
        ppi->type = pkt_type;
        ppi->ppi_offset = sizeof(struct rndis_per_packet_info);

        rndis_pkt->per_pkt_info_len += ppi_size;

        return ppi;
}

/* Azure hosts don't support non-TCP port numbers in hashing yet. We compute
 * hash for non-TCP traffic with only IP numbers.
 */
static inline u32 netvsc_get_hash(struct sk_buff *skb, struct sock *sk)
{
        struct flow_keys flow;
        u32 hash;
        static u32 hashrnd __read_mostly;

        net_get_random_once(&hashrnd, sizeof(hashrnd));

        if (!skb_flow_dissect_flow_keys(skb, &flow, 0))
                return 0;

        if (flow.basic.ip_proto == IPPROTO_TCP) {
                return skb_get_hash(skb);
        } else {
                if (flow.basic.n_proto == htons(ETH_P_IP))
                        hash = jhash2((u32 *)&flow.addrs.v4addrs, 2, hashrnd);
                else if (flow.basic.n_proto == htons(ETH_P_IPV6))
                        hash = jhash2((u32 *)&flow.addrs.v6addrs, 8, hashrnd);
                else
                        hash = 0;

                skb_set_hash(skb, hash, PKT_HASH_TYPE_L3);
        }

        return hash;
}

static inline int netvsc_get_tx_queue(struct net_device *ndev,
                                      struct sk_buff *skb, int old_idx)
{
        const struct net_device_context *ndc = netdev_priv(ndev);
        struct sock *sk = skb->sk;
        int q_idx;

        q_idx = ndc->tx_send_table[netvsc_get_hash(skb, sk) &
                                   (VRSS_SEND_TAB_SIZE - 1)];

        /* If queue index changed record the new value */
        if (q_idx != old_idx &&
            sk && sk_fullsock(sk) && rcu_access_pointer(sk->sk_dst_cache))
                sk_tx_queue_set(sk, q_idx);

        return q_idx;
}

/*
 * Select queue for transmit.
 *
 * If a valid queue has already been assigned, then use that.
 * Otherwise compute tx queue based on hash and the send table.
 *
 * This is basically similar to default (__netdev_pick_tx) with the added step
 * of using the host send_table when no other queue has been assigned.
 *
 * TODO support XPS - but get_xps_queue not exported
 */
static u16 netvsc_select_queue(struct net_device *ndev, struct sk_buff *skb,
                        void *accel_priv, select_queue_fallback_t fallback)
{
        unsigned int num_tx_queues = ndev->real_num_tx_queues;
        int q_idx = sk_tx_queue_get(skb->sk);

        if (q_idx < 0 || skb->ooo_okay) {
                /* If forwarding a packet, we use the recorded queue when
                 * available for better cache locality.
                 */
                if (skb_rx_queue_recorded(skb))
                        q_idx = skb_get_rx_queue(skb);
                else
                        q_idx = netvsc_get_tx_queue(ndev, skb, q_idx);
        }

        while (unlikely(q_idx >= num_tx_queues))
                q_idx -= num_tx_queues;

        return q_idx;
}

static u32 fill_pg_buf(struct page *page, u32 offset, u32 len,
                        struct hv_page_buffer *pb)
{
        int j = 0;

        /* Deal with compund pages by ignoring unused part
         * of the page.
         */
        page += (offset >> PAGE_SHIFT);
        offset &= ~PAGE_MASK;

        while (len > 0) {
                unsigned long bytes;

                bytes = PAGE_SIZE - offset;
                if (bytes > len)
                        bytes = len;
                pb[j].pfn = page_to_pfn(page);
                pb[j].offset = offset;
                pb[j].len = bytes;

                offset += bytes;
                len -= bytes;

                if (offset == PAGE_SIZE && len) {
                        page++;
                        offset = 0;
                        j++;
                }
        }

        return j + 1;
}

static u32 init_page_array(void *hdr, u32 len, struct sk_buff *skb,
                           struct hv_netvsc_packet *packet,
                           struct hv_page_buffer **page_buf)
{
        struct hv_page_buffer *pb = *page_buf;
        u32 slots_used = 0;
        char *data = skb->data;
        int frags = skb_shinfo(skb)->nr_frags;
        int i;

        /* The packet is laid out thus:
         * 1. hdr: RNDIS header and PPI
         * 2. skb linear data
         * 3. skb fragment data
         */
        if (hdr != NULL)
                slots_used += fill_pg_buf(virt_to_page(hdr),
                                        offset_in_page(hdr),
                                        len, &pb[slots_used]);

        packet->rmsg_size = len;
        packet->rmsg_pgcnt = slots_used;

        slots_used += fill_pg_buf(virt_to_page(data),
                                offset_in_page(data),
                                skb_headlen(skb), &pb[slots_used]);

        for (i = 0; i < frags; i++) {
                skb_frag_t *frag = skb_shinfo(skb)->frags + i;

                slots_used += fill_pg_buf(skb_frag_page(frag),
                                        frag->page_offset,
                                        skb_frag_size(frag), &pb[slots_used]);
        }
        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)
{
        return PFN_UP(offset_in_page(skb->data) + skb_headlen(skb))
                + skb_shinfo(skb)->nr_frags
                + 2;
}

static u32 net_checksum_info(struct sk_buff *skb)
{
        if (skb->protocol == htons(ETH_P_IP)) {
                struct iphdr *ip = ip_hdr(skb);

                if (ip->protocol == IPPROTO_TCP)
                        return TRANSPORT_INFO_IPV4_TCP;
                else if (ip->protocol == IPPROTO_UDP)
                        return TRANSPORT_INFO_IPV4_UDP;
        } else {
                struct ipv6hdr *ip6 = ipv6_hdr(skb);

                if (ip6->nexthdr == IPPROTO_TCP)
                        return TRANSPORT_INFO_IPV6_TCP;
                else if (ipv6_hdr(skb)->nexthdr == IPPROTO_UDP)
                        return TRANSPORT_INFO_IPV6_UDP;
        }

        return TRANSPORT_INFO_NOT_IP;
}

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 = NULL;
        int ret;
        unsigned int num_data_pgs;
        struct rndis_message *rndis_msg;
        struct rndis_packet *rndis_pkt;
        u32 rndis_msg_size;
        struct rndis_per_packet_info *ppi;
        u32 hash;
        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
         * of pages in a single packet. If skb is scattered around
         * more pages we try linearizing it.
         */
        num_data_pgs = netvsc_get_slots(skb);
        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);
                if (num_data_pgs > MAX_PAGE_BUFFER_COUNT) {
                        ++net_device_ctx->eth_stats.tx_too_big;
                        goto drop;
                }
        }

        /*
         * Place the rndis header in the skb head room and
         * the skb->cb will be used for hv_netvsc_packet
         * structure.
         */
        ret = skb_cow_head(skb, RNDIS_AND_PPI_SIZE);
        if (ret)
                goto no_memory;

        /* Use the skb control buffer for building up the packet */
        BUILD_BUG_ON(sizeof(struct hv_netvsc_packet) >
                        FIELD_SIZEOF(struct sk_buff, cb));
        packet = (struct hv_netvsc_packet *)skb->cb;

        packet->q_idx = skb_get_queue_mapping(skb);

        packet->total_data_buflen = skb->len;
        packet->total_bytes = skb->len;
        packet->total_packets = 1;

        rndis_msg = (struct rndis_message *)skb->head;

        memset(rndis_msg, 0, RNDIS_AND_PPI_SIZE);

        /* Add the rndis header */
        rndis_msg->ndis_msg_type = RNDIS_MSG_PACKET;
        rndis_msg->msg_len = packet->total_data_buflen;
        rndis_pkt = &rndis_msg->msg.pkt;
        rndis_pkt->data_offset = sizeof(struct rndis_packet);
        rndis_pkt->data_len = packet->total_data_buflen;
        rndis_pkt->per_pkt_info_offset = sizeof(struct rndis_packet);

        rndis_msg_size = RNDIS_MESSAGE_SIZE(struct rndis_packet);

        hash = skb_get_hash_raw(skb);
        if (hash != 0 && net->real_num_tx_queues > 1) {
                rndis_msg_size += NDIS_HASH_PPI_SIZE;
                ppi = init_ppi_data(rndis_msg, NDIS_HASH_PPI_SIZE,
                                    NBL_HASH_VALUE);
                *(u32 *)((void *)ppi + ppi->ppi_offset) = hash;
        }

        if (skb_vlan_tag_present(skb)) {
                struct ndis_pkt_8021q_info *vlan;

                rndis_msg_size += NDIS_VLAN_PPI_SIZE;
                ppi = init_ppi_data(rndis_msg, NDIS_VLAN_PPI_SIZE,
                                        IEEE_8021Q_INFO);
                vlan = (struct ndis_pkt_8021q_info *)((void *)ppi +
                                                ppi->ppi_offset);
                vlan->vlanid = skb->vlan_tci & VLAN_VID_MASK;
                vlan->pri = (skb->vlan_tci & VLAN_PRIO_MASK) >>
                                VLAN_PRIO_SHIFT;
        }

        if (skb_is_gso(skb)) {
                struct ndis_tcp_lso_info *lso_info;

                rndis_msg_size += NDIS_LSO_PPI_SIZE;
                ppi = init_ppi_data(rndis_msg, NDIS_LSO_PPI_SIZE,
                                    TCP_LARGESEND_PKTINFO);

                lso_info = (struct ndis_tcp_lso_info *)((void *)ppi +
                                                        ppi->ppi_offset);

                lso_info->lso_v2_transmit.type = NDIS_TCP_LARGE_SEND_OFFLOAD_V2_TYPE;
                if (skb->protocol == htons(ETH_P_IP)) {
                        lso_info->lso_v2_transmit.ip_version =
                                NDIS_TCP_LARGE_SEND_OFFLOAD_IPV4;
                        ip_hdr(skb)->tot_len = 0;
                        ip_hdr(skb)->check = 0;
                        tcp_hdr(skb)->check =
                                ~csum_tcpudp_magic(ip_hdr(skb)->saddr,
                                                   ip_hdr(skb)->daddr, 0, IPPROTO_TCP, 0);
                } else {
                        lso_info->lso_v2_transmit.ip_version =
                                NDIS_TCP_LARGE_SEND_OFFLOAD_IPV6;
                        ipv6_hdr(skb)->payload_len = 0;
                        tcp_hdr(skb)->check =
                                ~csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
                                                 &ipv6_hdr(skb)->daddr, 0, IPPROTO_TCP, 0);
                }
                lso_info->lso_v2_transmit.tcp_header_offset = skb_transport_offset(skb);
                lso_info->lso_v2_transmit.mss = skb_shinfo(skb)->gso_size;
        } else if (skb->ip_summed == CHECKSUM_PARTIAL) {
                if (net_checksum_info(skb) & net_device_ctx->tx_checksum_mask) {
                        struct ndis_tcp_ip_checksum_info *csum_info;

                        rndis_msg_size += NDIS_CSUM_PPI_SIZE;
                        ppi = init_ppi_data(rndis_msg, NDIS_CSUM_PPI_SIZE,
                                            TCPIP_CHKSUM_PKTINFO);

                        csum_info = (struct ndis_tcp_ip_checksum_info *)((void *)ppi +
                                                                         ppi->ppi_offset);

                        csum_info->transmit.tcp_header_offset = skb_transport_offset(skb);

                        if (skb->protocol == htons(ETH_P_IP)) {
                                csum_info->transmit.is_ipv4 = 1;

                                if (ip_hdr(skb)->protocol == IPPROTO_TCP)
                                        csum_info->transmit.tcp_checksum = 1;
                                else
                                        csum_info->transmit.udp_checksum = 1;
                        } else {
                                csum_info->transmit.is_ipv6 = 1;

                                if (ipv6_hdr(skb)->nexthdr == IPPROTO_TCP)
                                        csum_info->transmit.tcp_checksum = 1;
                                else
                                        csum_info->transmit.udp_checksum = 1;
                        }
                } else {
                        /* Can't do offload of this type of checksum */
                        if (skb_checksum_help(skb))
                                goto drop;
                }
        }

        /* Start filling in the page buffers with the rndis hdr */
        rndis_msg->msg_len += rndis_msg_size;
        packet->total_data_buflen = rndis_msg->msg_len;
        packet->page_buf_cnt = init_page_array(rndis_msg, rndis_msg_size,
                                               skb, packet, &pb);

        /* timestamp packet in software */
        skb_tx_timestamp(skb);

        ret = netvsc_send(net_device_ctx, packet, rndis_msg, &pb, skb);
        if (likely(ret == 0))
                return NETDEV_TX_OK;

        if (ret == -EAGAIN) {
                ++net_device_ctx->eth_stats.tx_busy;
                return NETDEV_TX_BUSY;
        }

        if (ret == -ENOSPC)
                ++net_device_ctx->eth_stats.tx_no_space;

drop:
        dev_kfree_skb_any(skb);
        net->stats.tx_dropped++;

        return NETDEV_TX_OK;

no_memory:
        ++net_device_ctx->eth_stats.tx_no_memory;
        goto drop;
}
/*
 * netvsc_linkstatus_callback - Link up/down notification
 */
void netvsc_linkstatus_callback(struct hv_device *device_obj,
                                struct rndis_message *resp)
{
        struct rndis_indicate_status *indicate = &resp->msg.indicate_status;
        struct net_device *net;
        struct net_device_context *ndev_ctx;
        struct netvsc_reconfig *event;
        unsigned long flags;

        net = hv_get_drvdata(device_obj);

        if (!net)
                return;

        ndev_ctx = netdev_priv(net);

        /* Update the physical link speed when changing to another vSwitch */
        if (indicate->status == RNDIS_STATUS_LINK_SPEED_CHANGE) {
                u32 speed;

                speed = *(u32 *)((void *)indicate + indicate->
                                 status_buf_offset) / 10000;
                ndev_ctx->speed = speed;
                return;
        }

        /* Handle these link change statuses below */
        if (indicate->status != RNDIS_STATUS_NETWORK_CHANGE &&
            indicate->status != RNDIS_STATUS_MEDIA_CONNECT &&
            indicate->status != RNDIS_STATUS_MEDIA_DISCONNECT)
                return;

        if (net->reg_state != NETREG_REGISTERED)
                return;

        event = kzalloc(sizeof(*event), GFP_ATOMIC);
        if (!event)
                return;
        event->event = indicate->status;

        spin_lock_irqsave(&ndev_ctx->lock, flags);
        list_add_tail(&event->list, &ndev_ctx->reconfig_events);
        spin_unlock_irqrestore(&ndev_ctx->lock, flags);

        schedule_delayed_work(&ndev_ctx->dwork, 0);
}

static struct sk_buff *netvsc_alloc_recv_skb(struct net_device *net,
                                             struct napi_struct *napi,
                                             const struct ndis_tcp_ip_checksum_info *csum_info,
                                             const struct ndis_pkt_8021q_info *vlan,
                                             void *data, u32 buflen)
{
        struct sk_buff *skb;

        skb = napi_alloc_skb(napi, buflen);
        if (!skb)
                return skb;

        /*
         * Copy to skb. This copy is needed here since the memory pointed by
         * hv_netvsc_packet cannot be deallocated
         */
        skb_put_data(skb, data, buflen);

        skb->protocol = eth_type_trans(skb, net);

        /* skb is already created with CHECKSUM_NONE */
        skb_checksum_none_assert(skb);

        /*
         * In Linux, the IP checksum is always checked.
         * Do L4 checksum offload if enabled and present.
         */
        if (csum_info && (net->features & NETIF_F_RXCSUM)) {
                if (csum_info->receive.tcp_checksum_succeeded ||
                    csum_info->receive.udp_checksum_succeeded)
                        skb->ip_summed = CHECKSUM_UNNECESSARY;
        }

        if (vlan) {
                u16 vlan_tci = vlan->vlanid | (vlan->pri << VLAN_PRIO_SHIFT);

                __vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q),
                                       vlan_tci);
        }

        return skb;
}

/*
 * netvsc_recv_callback -  Callback when we receive a packet from the
 * "wire" on the specified device.
 */
int netvsc_recv_callback(struct net_device *net,
                         struct vmbus_channel *channel,
                         void  *data, u32 len,
                         const struct ndis_tcp_ip_checksum_info *csum_info,
                         const struct ndis_pkt_8021q_info *vlan)
{
        struct net_device_context *net_device_ctx = netdev_priv(net);
        struct netvsc_device *net_device;
        u16 q_idx = channel->offermsg.offer.sub_channel_index;
        struct netvsc_channel *nvchan;
        struct net_device *vf_netdev;
        struct sk_buff *skb;
        struct netvsc_stats *rx_stats;

        if (net->reg_state != NETREG_REGISTERED)
                return NVSP_STAT_FAIL;

        /*
         * If necessary, inject this packet into the VF interface.
         * On Hyper-V, multicast and brodcast packets are only delivered
         * to the synthetic interface (after subjecting these to
         * policy filters on the host). Deliver these via the VF
         * interface in the guest.
         */
        rcu_read_lock();
        net_device = rcu_dereference(net_device_ctx->nvdev);
        if (unlikely(!net_device))
                goto drop;

        nvchan = &net_device->chan_table[q_idx];
        vf_netdev = rcu_dereference(net_device_ctx->vf_netdev);
        if (vf_netdev && (vf_netdev->flags & IFF_UP))
                net = vf_netdev;

        /* Allocate a skb - TODO direct I/O to pages? */
        skb = netvsc_alloc_recv_skb(net, &nvchan->napi,
                                    csum_info, vlan, data, len);
        if (unlikely(!skb)) {
drop:
                ++net->stats.rx_dropped;
                rcu_read_unlock();
                return NVSP_STAT_FAIL;
        }

        if (net != vf_netdev)
                skb_record_rx_queue(skb, q_idx);

        /*
         * Even if injecting the packet, record the statistics
         * on the synthetic device because modifying the VF device
         * statistics will not work correctly.
         */
        rx_stats = &nvchan->rx_stats;
        u64_stats_update_begin(&rx_stats->syncp);
        rx_stats->packets++;
        rx_stats->bytes += len;

        if (skb->pkt_type == PACKET_BROADCAST)
                ++rx_stats->broadcast;
        else if (skb->pkt_type == PACKET_MULTICAST)
                ++rx_stats->multicast;
        u64_stats_update_end(&rx_stats->syncp);

        napi_gro_receive(&nvchan->napi, skb);
        rcu_read_unlock();

        return 0;
}

static void netvsc_get_drvinfo(struct net_device *net,
                               struct ethtool_drvinfo *info)
{
        strlcpy(info->driver, KBUILD_MODNAME, sizeof(info->driver));
        strlcpy(info->fw_version, "N/A", sizeof(info->fw_version));
}

static void netvsc_get_channels(struct net_device *net,
                                struct ethtool_channels *channel)
{
        struct net_device_context *net_device_ctx = netdev_priv(net);
        struct netvsc_device *nvdev = rtnl_dereference(net_device_ctx->nvdev);

        if (nvdev) {
                channel->max_combined   = nvdev->max_chn;
                channel->combined_count = nvdev->num_chn;
        }
}

static int netvsc_set_queues(struct net_device *net, struct hv_device *dev,
                             u32 num_chn)
{
        struct netvsc_device_info device_info;
        struct netvsc_device *net_device;
        int ret;

        memset(&device_info, 0, sizeof(device_info));
        device_info.num_chn = num_chn;
        device_info.ring_size = ring_size;
        device_info.max_num_vrss_chns = num_chn;

        ret = netif_set_real_num_tx_queues(net, num_chn);
        if (ret)
                return ret;

        ret = netif_set_real_num_rx_queues(net, num_chn);
        if (ret)
                return ret;

        net_device = rndis_filter_device_add(dev, &device_info);
        return IS_ERR(net_device) ? PTR_ERR(net_device) : 0;
}

static int netvsc_set_channels(struct net_device *net,
                               struct ethtool_channels *channels)
{
        struct net_device_context *net_device_ctx = netdev_priv(net);
        struct hv_device *dev = net_device_ctx->device_ctx;
        struct netvsc_device *nvdev = rtnl_dereference(net_device_ctx->nvdev);
        unsigned int count = channels->combined_count;
        bool was_opened;
        int ret;

        /* We do not support separate count for rx, tx, or other */
        if (count == 0 ||
            channels->rx_count || channels->tx_count || channels->other_count)
                return -EINVAL;

        if (count > net->num_tx_queues || count > VRSS_CHANNEL_MAX)
                return -EINVAL;

        if (!nvdev || nvdev->destroy)
                return -ENODEV;

        if (nvdev->nvsp_version < NVSP_PROTOCOL_VERSION_5)
                return -EINVAL;

        if (count > nvdev->max_chn)
                return -EINVAL;

        was_opened = rndis_filter_opened(nvdev);
        if (was_opened)
                rndis_filter_close(nvdev);

        rndis_filter_device_remove(dev, nvdev);

        ret = netvsc_set_queues(net, dev, count);
        if (ret == 0)
                nvdev->num_chn = count;
        else
                netvsc_set_queues(net, dev, nvdev->num_chn);

        nvdev = rtnl_dereference(net_device_ctx->nvdev);
        if (was_opened)
                rndis_filter_open(nvdev);

        /* We may have missed link change notifications */
        net_device_ctx->last_reconfig = 0;
        schedule_delayed_work(&net_device_ctx->dwork, 0);

        return ret;
}

static bool
netvsc_validate_ethtool_ss_cmd(const struct ethtool_link_ksettings *cmd)
{
        struct ethtool_link_ksettings diff1 = *cmd;
        struct ethtool_link_ksettings diff2 = {};

        diff1.base.speed = 0;
        diff1.base.duplex = 0;
        /* advertising and cmd are usually set */
        ethtool_link_ksettings_zero_link_mode(&diff1, advertising);
        diff1.base.cmd = 0;
        /* We set port to PORT_OTHER */
        diff2.base.port = PORT_OTHER;

        return !memcmp(&diff1, &diff2, sizeof(diff1));
}

static void netvsc_init_settings(struct net_device *dev)
{
        struct net_device_context *ndc = netdev_priv(dev);

        ndc->speed = SPEED_UNKNOWN;
        ndc->duplex = DUPLEX_FULL;
}

static int netvsc_get_link_ksettings(struct net_device *dev,
                                     struct ethtool_link_ksettings *cmd)
{
        struct net_device_context *ndc = netdev_priv(dev);

        cmd->base.speed = ndc->speed;
        cmd->base.duplex = ndc->duplex;
        cmd->base.port = PORT_OTHER;

        return 0;
}

static int netvsc_set_link_ksettings(struct net_device *dev,
                                     const struct ethtool_link_ksettings *cmd)
{
        struct net_device_context *ndc = netdev_priv(dev);
        u32 speed;

        speed = cmd->base.speed;
        if (!ethtool_validate_speed(speed) ||
            !ethtool_validate_duplex(cmd->base.duplex) ||
            !netvsc_validate_ethtool_ss_cmd(cmd))
                return -EINVAL;

        ndc->speed = speed;
        ndc->duplex = cmd->base.duplex;

        return 0;
}

static int netvsc_change_mtu(struct net_device *ndev, int mtu)
{
        struct net_device_context *ndevctx = netdev_priv(ndev);
        struct netvsc_device *nvdev = rtnl_dereference(ndevctx->nvdev);
        struct hv_device *hdev = ndevctx->device_ctx;
        int orig_mtu = ndev->mtu;
        struct netvsc_device_info device_info;
        bool was_opened;
        int ret = 0;

        if (!nvdev || nvdev->destroy)
                return -ENODEV;

        netif_device_detach(ndev);
        was_opened = rndis_filter_opened(nvdev);
        if (was_opened)
                rndis_filter_close(nvdev);

        memset(&device_info, 0, sizeof(device_info));
        device_info.ring_size = ring_size;
        device_info.num_chn = nvdev->num_chn;
        device_info.max_num_vrss_chns = nvdev->num_chn;

        rndis_filter_device_remove(hdev, nvdev);

        ndev->mtu = mtu;

        nvdev = rndis_filter_device_add(hdev, &device_info);
        if (IS_ERR(nvdev)) {
                ret = PTR_ERR(nvdev);

                /* Attempt rollback to original MTU */
                ndev->mtu = orig_mtu;
                rndis_filter_device_add(hdev, &device_info);
        }

        if (was_opened)
                rndis_filter_open(nvdev);

        netif_device_attach(ndev);

        /* We may have missed link change notifications */
        schedule_delayed_work(&ndevctx->dwork, 0);

        return ret;
}

static void netvsc_get_stats64(struct net_device *net,
                               struct rtnl_link_stats64 *t)
{
        struct net_device_context *ndev_ctx = netdev_priv(net);
        struct netvsc_device *nvdev = rcu_dereference_rtnl(ndev_ctx->nvdev);
        int i;

        if (!nvdev)
                return;

        for (i = 0; i < nvdev->num_chn; i++) {
                const struct netvsc_channel *nvchan = &nvdev->chan_table[i];
                const struct netvsc_stats *stats;
                u64 packets, bytes, multicast;
                unsigned int start;

                stats = &nvchan->tx_stats;
                do {
                        start = u64_stats_fetch_begin_irq(&stats->syncp);
                        packets = stats->packets;
                        bytes = stats->bytes;
                } while (u64_stats_fetch_retry_irq(&stats->syncp, start));

                t->tx_bytes     += bytes;
                t->tx_packets   += packets;

                stats = &nvchan->rx_stats;
                do {
                        start = u64_stats_fetch_begin_irq(&stats->syncp);
                        packets = stats->packets;
                        bytes = stats->bytes;
                        multicast = stats->multicast + stats->broadcast;
                } while (u64_stats_fetch_retry_irq(&stats->syncp, start));

                t->rx_bytes     += bytes;
                t->rx_packets   += packets;
                t->multicast    += multicast;
        }

        t->tx_dropped   = net->stats.tx_dropped;
        t->tx_errors    = net->stats.tx_errors;

        t->rx_dropped   = net->stats.rx_dropped;
        t->rx_errors    = net->stats.rx_errors;
}

static int netvsc_set_mac_addr(struct net_device *ndev, void *p)
{
        struct sockaddr *addr = p;
        char save_adr[ETH_ALEN];
        unsigned char save_aatype;
        int err;

        memcpy(save_adr, ndev->dev_addr, ETH_ALEN);
        save_aatype = ndev->addr_assign_type;

        err = eth_mac_addr(ndev, p);
        if (err != 0)
                return err;

        err = rndis_filter_set_device_mac(ndev, addr->sa_data);
        if (err != 0) {
                /* roll back to saved MAC */
                memcpy(ndev->dev_addr, save_adr, ETH_ALEN);
                ndev->addr_assign_type = save_aatype;
        }

        return err;
}

static const struct {
        char name[ETH_GSTRING_LEN];
        u16 offset;
} netvsc_stats[] = {
        { "tx_scattered", offsetof(struct netvsc_ethtool_stats, tx_scattered) },
        { "tx_no_memory",  offsetof(struct netvsc_ethtool_stats, tx_no_memory) },
        { "tx_no_space",  offsetof(struct netvsc_ethtool_stats, tx_no_space) },
        { "tx_too_big",   offsetof(struct netvsc_ethtool_stats, tx_too_big) },
        { "tx_busy",      offsetof(struct netvsc_ethtool_stats, tx_busy) },
};

#define NETVSC_GLOBAL_STATS_LEN ARRAY_SIZE(netvsc_stats)

/* 4 statistics per queue (rx/tx packets/bytes) */
#define NETVSC_QUEUE_STATS_LEN(dev) ((dev)->num_chn * 4)

static int netvsc_get_sset_count(struct net_device *dev, int string_set)
{
        struct net_device_context *ndc = netdev_priv(dev);
        struct netvsc_device *nvdev = rtnl_dereference(ndc->nvdev);

        if (!nvdev)
                return -ENODEV;

        switch (string_set) {
        case ETH_SS_STATS:
                return NETVSC_GLOBAL_STATS_LEN + NETVSC_QUEUE_STATS_LEN(nvdev);
        default:
                return -EINVAL;
        }
}

static void netvsc_get_ethtool_stats(struct net_device *dev,
                                     struct ethtool_stats *stats, u64 *data)
{
        struct net_device_context *ndc = netdev_priv(dev);
        struct netvsc_device *nvdev = rcu_dereference(ndc->nvdev);
        const void *nds = &ndc->eth_stats;
        const struct netvsc_stats *qstats;
        unsigned int start;
        u64 packets, bytes;
        int i, j;

        if (!nvdev)
                return;

        for (i = 0; i < NETVSC_GLOBAL_STATS_LEN; i++)
                data[i] = *(unsigned long *)(nds + netvsc_stats[i].offset);

        for (j = 0; j < nvdev->num_chn; j++) {
                qstats = &nvdev->chan_table[j].tx_stats;

                do {
                        start = u64_stats_fetch_begin_irq(&qstats->syncp);
                        packets = qstats->packets;
                        bytes = qstats->bytes;
                } while (u64_stats_fetch_retry_irq(&qstats->syncp, start));
                data[i++] = packets;
                data[i++] = bytes;

                qstats = &nvdev->chan_table[j].rx_stats;
                do {
                        start = u64_stats_fetch_begin_irq(&qstats->syncp);
                        packets = qstats->packets;
                        bytes = qstats->bytes;
                } while (u64_stats_fetch_retry_irq(&qstats->syncp, start));
                data[i++] = packets;
                data[i++] = bytes;
        }
}

static void netvsc_get_strings(struct net_device *dev, u32 stringset, u8 *data)
{
        struct net_device_context *ndc = netdev_priv(dev);
        struct netvsc_device *nvdev = rcu_dereference(ndc->nvdev);
        u8 *p = data;
        int i;

        if (!nvdev)
                return;

        switch (stringset) {
        case ETH_SS_STATS:
                for (i = 0; i < ARRAY_SIZE(netvsc_stats); i++)
                        memcpy(p + i * ETH_GSTRING_LEN,
                               netvsc_stats[i].name, ETH_GSTRING_LEN);

                p += i * ETH_GSTRING_LEN;
                for (i = 0; i < nvdev->num_chn; i++) {
                        sprintf(p, "tx_queue_%u_packets", i);
                        p += ETH_GSTRING_LEN;
                        sprintf(p, "tx_queue_%u_bytes", i);
                        p += ETH_GSTRING_LEN;
                        sprintf(p, "rx_queue_%u_packets", i);
                        p += ETH_GSTRING_LEN;
                        sprintf(p, "rx_queue_%u_bytes", i);
                        p += ETH_GSTRING_LEN;
                }

                break;
        }
}

static int
netvsc_get_rss_hash_opts(struct netvsc_device *nvdev,
                         struct ethtool_rxnfc *info)
{
        info->data = RXH_IP_SRC | RXH_IP_DST;

        switch (info->flow_type) {
        case TCP_V4_FLOW:
        case TCP_V6_FLOW:
                info->data |= RXH_L4_B_0_1 | RXH_L4_B_2_3;
                /* fallthrough */
        case UDP_V4_FLOW:
        case UDP_V6_FLOW:
        case IPV4_FLOW:
        case IPV6_FLOW:
                break;
        default:
                info->data = 0;
                break;
        }

        return 0;
}

static int
netvsc_get_rxnfc(struct net_device *dev, struct ethtool_rxnfc *info,
                 u32 *rules)
{
        struct net_device_context *ndc = netdev_priv(dev);
        struct netvsc_device *nvdev = rcu_dereference(ndc->nvdev);

        if (!nvdev)
                return -ENODEV;

        switch (info->cmd) {
        case ETHTOOL_GRXRINGS:
                info->data = nvdev->num_chn;
                return 0;

        case ETHTOOL_GRXFH:
                return netvsc_get_rss_hash_opts(nvdev, info);
        }
        return -EOPNOTSUPP;
}

#ifdef CONFIG_NET_POLL_CONTROLLER
static void netvsc_poll_controller(struct net_device *dev)
{
        struct net_device_context *ndc = netdev_priv(dev);
        struct netvsc_device *ndev;
        int i;

        rcu_read_lock();
        ndev = rcu_dereference(ndc->nvdev);
        if (ndev) {
                for (i = 0; i < ndev->num_chn; i++) {
                        struct netvsc_channel *nvchan = &ndev->chan_table[i];

                        napi_schedule(&nvchan->napi);
                }
        }
        rcu_read_unlock();
}
#endif

static u32 netvsc_get_rxfh_key_size(struct net_device *dev)
{
        return NETVSC_HASH_KEYLEN;
}

static u32 netvsc_rss_indir_size(struct net_device *dev)
{
        return ITAB_NUM;
}

static int netvsc_get_rxfh(struct net_device *dev, u32 *indir, u8 *key,
                           u8 *hfunc)
{
        struct net_device_context *ndc = netdev_priv(dev);
        struct netvsc_device *ndev = rcu_dereference(ndc->nvdev);
        struct rndis_device *rndis_dev;
        int i;

        if (!ndev)
                return -ENODEV;

        if (hfunc)
                *hfunc = ETH_RSS_HASH_TOP;      /* Toeplitz */

        rndis_dev = ndev->extension;
        if (indir) {
                for (i = 0; i < ITAB_NUM; i++)
                        indir[i] = rndis_dev->ind_table[i];
        }

        if (key)
                memcpy(key, rndis_dev->rss_key, NETVSC_HASH_KEYLEN);

        return 0;
}

static int netvsc_set_rxfh(struct net_device *dev, const u32 *indir,
                           const u8 *key, const u8 hfunc)
{
        struct net_device_context *ndc = netdev_priv(dev);
        struct netvsc_device *ndev = rtnl_dereference(ndc->nvdev);
        struct rndis_device *rndis_dev;
        int i;

        if (!ndev)
                return -ENODEV;

        if (hfunc != ETH_RSS_HASH_NO_CHANGE && hfunc != ETH_RSS_HASH_TOP)
                return -EOPNOTSUPP;

        rndis_dev = ndev->extension;
        if (indir) {
                for (i = 0; i < ITAB_NUM; i++)
                        if (indir[i] >= VRSS_CHANNEL_MAX)
                                return -EINVAL;

                for (i = 0; i < ITAB_NUM; i++)
                        rndis_dev->ind_table[i] = indir[i];
        }

        if (!key) {
                if (!indir)
                        return 0;

                key = rndis_dev->rss_key;
        }

        return rndis_filter_set_rss_param(rndis_dev, key, ndev->num_chn);
}

static const struct ethtool_ops ethtool_ops = {
        .get_drvinfo    = netvsc_get_drvinfo,
        .get_link       = ethtool_op_get_link,
        .get_ethtool_stats = netvsc_get_ethtool_stats,
        .get_sset_count = netvsc_get_sset_count,
        .get_strings    = netvsc_get_strings,
        .get_channels   = netvsc_get_channels,
        .set_channels   = netvsc_set_channels,
        .get_ts_info    = ethtool_op_get_ts_info,
        .get_rxnfc      = netvsc_get_rxnfc,
        .get_rxfh_key_size = netvsc_get_rxfh_key_size,
        .get_rxfh_indir_size = netvsc_rss_indir_size,
        .get_rxfh       = netvsc_get_rxfh,
        .set_rxfh       = netvsc_set_rxfh,
        .get_link_ksettings = netvsc_get_link_ksettings,
        .set_link_ksettings = netvsc_set_link_ksettings,
};

static const struct net_device_ops device_ops = {
        .ndo_open =                     netvsc_open,
        .ndo_stop =                     netvsc_close,
        .ndo_start_xmit =               netvsc_start_xmit,
        .ndo_set_rx_mode =              netvsc_set_multicast_list,
        .ndo_change_mtu =               netvsc_change_mtu,
        .ndo_validate_addr =            eth_validate_addr,
        .ndo_set_mac_address =          netvsc_set_mac_addr,
        .ndo_select_queue =             netvsc_select_queue,
        .ndo_get_stats64 =              netvsc_get_stats64,
#ifdef CONFIG_NET_POLL_CONTROLLER
        .ndo_poll_controller =          netvsc_poll_controller,
#endif
};

/*
 * Handle link status changes. For RNDIS_STATUS_NETWORK_CHANGE emulate link
 * down/up sequence. In case of RNDIS_STATUS_MEDIA_CONNECT when carrier is
 * present send GARP packet to network peers with netif_notify_peers().
 */
static void netvsc_link_change(struct work_struct *w)
{
        struct net_device_context *ndev_ctx =
                container_of(w, struct net_device_context, dwork.work);
        struct hv_device *device_obj = ndev_ctx->device_ctx;
        struct net_device *net = hv_get_drvdata(device_obj);
        struct netvsc_device *net_device;
        struct rndis_device *rdev;
        struct netvsc_reconfig *event = NULL;
        bool notify = false, reschedule = false;
        unsigned long flags, next_reconfig, delay;

        rtnl_lock();
        net_device = rtnl_dereference(ndev_ctx->nvdev);
        if (!net_device)
                goto out_unlock;

        rdev = net_device->extension;

        next_reconfig = ndev_ctx->last_reconfig + LINKCHANGE_INT;
        if (time_is_after_jiffies(next_reconfig)) {
                /* link_watch only sends one notification with current state
                 * per second, avoid doing reconfig more frequently. Handle
                 * wrap around.
                 */
                delay = next_reconfig - jiffies;
                delay = delay < LINKCHANGE_INT ? delay : LINKCHANGE_INT;
                schedule_delayed_work(&ndev_ctx->dwork, delay);
                goto out_unlock;
        }
        ndev_ctx->last_reconfig = jiffies;

        spin_lock_irqsave(&ndev_ctx->lock, flags);
        if (!list_empty(&ndev_ctx->reconfig_events)) {
                event = list_first_entry(&ndev_ctx->reconfig_events,
                                         struct netvsc_reconfig, list);
                list_del(&event->list);
                reschedule = !list_empty(&ndev_ctx->reconfig_events);
        }
        spin_unlock_irqrestore(&ndev_ctx->lock, flags);

        if (!event)
                goto out_unlock;

        switch (event->event) {
                /* Only the following events are possible due to the check in
                 * netvsc_linkstatus_callback()
                 */
        case RNDIS_STATUS_MEDIA_CONNECT:
                if (rdev->link_state) {
                        rdev->link_state = false;
                        if (!ndev_ctx->datapath)
                                netif_carrier_on(net);
                        netif_tx_wake_all_queues(net);
                } else {
                        notify = true;
                }
                kfree(event);
                break;
        case RNDIS_STATUS_MEDIA_DISCONNECT:
                if (!rdev->link_state) {
                        rdev->link_state = true;
                        netif_carrier_off(net);
                        netif_tx_stop_all_queues(net);
                }
                kfree(event);
                break;
        case RNDIS_STATUS_NETWORK_CHANGE:
                /* Only makes sense if carrier is present */
                if (!rdev->link_state) {
                        rdev->link_state = true;
                        netif_carrier_off(net);
                        netif_tx_stop_all_queues(net);
                        event->event = RNDIS_STATUS_MEDIA_CONNECT;
                        spin_lock_irqsave(&ndev_ctx->lock, flags);
                        list_add(&event->list, &ndev_ctx->reconfig_events);
                        spin_unlock_irqrestore(&ndev_ctx->lock, flags);
                        reschedule = true;
                }
                break;
        }

        rtnl_unlock();

        if (notify)
                netdev_notify_peers(net);

        /* link_watch only sends one notification with current state per
         * second, handle next reconfig event in 2 seconds.
         */
        if (reschedule)
                schedule_delayed_work(&ndev_ctx->dwork, LINKCHANGE_INT);

        return;

out_unlock:
        rtnl_unlock();
}

static struct net_device *get_netvsc_bymac(const u8 *mac)
{
        struct net_device *dev;

        ASSERT_RTNL();

        for_each_netdev(&init_net, dev) {
                if (dev->netdev_ops != &device_ops)
                        continue;       /* not a netvsc device */

                if (ether_addr_equal(mac, dev->perm_addr))
                        return dev;
        }

        return NULL;
}

static struct net_device *get_netvsc_byref(struct net_device *vf_netdev)
{
        struct net_device *dev;

        ASSERT_RTNL();

        for_each_netdev(&init_net, dev) {
                struct net_device_context *net_device_ctx;

                if (dev->netdev_ops != &device_ops)
                        continue;       /* not a netvsc device */

                net_device_ctx = netdev_priv(dev);
                if (!rtnl_dereference(net_device_ctx->nvdev))
                        continue;       /* device is removed */

                if (rtnl_dereference(net_device_ctx->vf_netdev) == vf_netdev)
                        return dev;     /* a match */
        }

        return NULL;
}

static int netvsc_register_vf(struct net_device *vf_netdev)
{
        struct net_device *ndev;
        struct net_device_context *net_device_ctx;
        struct netvsc_device *netvsc_dev;

        if (vf_netdev->addr_len != ETH_ALEN)
                return NOTIFY_DONE;

        /*
         * We will use the MAC address to locate the synthetic interface to
         * associate with the VF interface. If we don't find a matching
         * synthetic interface, move on.
         */
        ndev = get_netvsc_bymac(vf_netdev->perm_addr);
        if (!ndev)
                return NOTIFY_DONE;

        net_device_ctx = netdev_priv(ndev);
        netvsc_dev = rtnl_dereference(net_device_ctx->nvdev);
        if (!netvsc_dev || rtnl_dereference(net_device_ctx->vf_netdev))
                return NOTIFY_DONE;

        netdev_info(ndev, "VF registering: %s\n", vf_netdev->name);
        /*
         * Take a reference on the module.
         */
        try_module_get(THIS_MODULE);

        dev_hold(vf_netdev);
        rcu_assign_pointer(net_device_ctx->vf_netdev, vf_netdev);
        return NOTIFY_OK;
}

static int netvsc_vf_up(struct net_device *vf_netdev)
{
        struct net_device *ndev;
        struct netvsc_device *netvsc_dev;
        struct net_device_context *net_device_ctx;

        ndev = get_netvsc_byref(vf_netdev);
        if (!ndev)
                return NOTIFY_DONE;

        net_device_ctx = netdev_priv(ndev);
        netvsc_dev = rtnl_dereference(net_device_ctx->nvdev);

        netdev_info(ndev, "VF up: %s\n", vf_netdev->name);

        /*
         * Open the device before switching data path.
         */
        rndis_filter_open(netvsc_dev);

        /*
         * notify the host to switch the data path.
         */
        netvsc_switch_datapath(ndev, true);
        netdev_info(ndev, "Data path switched to VF: %s\n", vf_netdev->name);

        netif_carrier_off(ndev);

        /* Now notify peers through VF device. */
        call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, vf_netdev);

        return NOTIFY_OK;
}

static int netvsc_vf_down(struct net_device *vf_netdev)
{
        struct net_device *ndev;
        struct netvsc_device *netvsc_dev;
        struct net_device_context *net_device_ctx;

        ndev = get_netvsc_byref(vf_netdev);
        if (!ndev)
                return NOTIFY_DONE;

        net_device_ctx = netdev_priv(ndev);
        netvsc_dev = rtnl_dereference(net_device_ctx->nvdev);

        netdev_info(ndev, "VF down: %s\n", vf_netdev->name);
        netvsc_switch_datapath(ndev, false);
        netdev_info(ndev, "Data path switched from VF: %s\n", vf_netdev->name);
        rndis_filter_close(netvsc_dev);
        netif_carrier_on(ndev);

        /* Now notify peers through netvsc device. */
        call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, ndev);

        return NOTIFY_OK;
}

static int netvsc_unregister_vf(struct net_device *vf_netdev)
{
        struct net_device *ndev;
        struct net_device_context *net_device_ctx;

        ndev = get_netvsc_byref(vf_netdev);
        if (!ndev)
                return NOTIFY_DONE;

        net_device_ctx = netdev_priv(ndev);

        netdev_info(ndev, "VF unregistering: %s\n", vf_netdev->name);

        RCU_INIT_POINTER(net_device_ctx->vf_netdev, NULL);
        dev_put(vf_netdev);
        module_put(THIS_MODULE);
        return NOTIFY_OK;
}

static int netvsc_probe(struct hv_device *dev,
                        const struct hv_vmbus_device_id *dev_id)
{
        struct net_device *net = NULL;
        struct net_device_context *net_device_ctx;
        struct netvsc_device_info device_info;
        struct netvsc_device *nvdev;
        int ret;

        net = alloc_etherdev_mq(sizeof(struct net_device_context),
                                VRSS_CHANNEL_MAX);
        if (!net)
                return -ENOMEM;

        netif_carrier_off(net);

        netvsc_init_settings(net);

        net_device_ctx = netdev_priv(net);
        net_device_ctx->device_ctx = dev;
        net_device_ctx->msg_enable = netif_msg_init(debug, default_msg);
        if (netif_msg_probe(net_device_ctx))
                netdev_dbg(net, "netvsc msg_enable: %d\n",
                           net_device_ctx->msg_enable);

        hv_set_drvdata(dev, net);

        INIT_DELAYED_WORK(&net_device_ctx->dwork, netvsc_link_change);

        spin_lock_init(&net_device_ctx->lock);
        INIT_LIST_HEAD(&net_device_ctx->reconfig_events);

        net->netdev_ops = &device_ops;
        net->ethtool_ops = &ethtool_ops;
        SET_NETDEV_DEV(net, &dev->device);

        /* We always need headroom for rndis header */
        net->needed_headroom = RNDIS_AND_PPI_SIZE;

        /* Notify the netvsc driver of the new device */
        memset(&device_info, 0, sizeof(device_info));
        device_info.ring_size = ring_size;
        device_info.num_chn = VRSS_CHANNEL_DEFAULT;

        nvdev = rndis_filter_device_add(dev, &device_info);
        if (IS_ERR(nvdev)) {
                ret = PTR_ERR(nvdev);
                netdev_err(net, "unable to add netvsc device (ret %d)\n", ret);
                free_netdev(net);
                hv_set_drvdata(dev, NULL);
                return ret;
        }
        memcpy(net->dev_addr, device_info.mac_adr, ETH_ALEN);

        /* hw_features computed in rndis_filter_device_add */
        net->features = net->hw_features |
                NETIF_F_HIGHDMA | NETIF_F_SG |
                NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX;
        net->vlan_features = net->features;

        netif_set_real_num_tx_queues(net, nvdev->num_chn);
        netif_set_real_num_rx_queues(net, nvdev->num_chn);
        rtnl_unlock();

        netdev_lockdep_set_classes(net);

        /* MTU range: 68 - 1500 or 65521 */
        net->min_mtu = NETVSC_MTU_MIN;
        if (nvdev->nvsp_version >= NVSP_PROTOCOL_VERSION_2)
                net->max_mtu = NETVSC_MTU - ETH_HLEN;
        else
                net->max_mtu = ETH_DATA_LEN;

        ret = register_netdev(net);
        if (ret != 0) {
                pr_err("Unable to register netdev.\n");
                rndis_filter_device_remove(dev, nvdev);
                free_netdev(net);
        }

        return ret;
}

static int netvsc_remove(struct hv_device *dev)
{
        struct net_device *net;
        struct net_device_context *ndev_ctx;

        net = hv_get_drvdata(dev);

        if (net == NULL) {
                dev_err(&dev->device, "No net device to remove\n");
                return 0;
        }

        ndev_ctx = netdev_priv(net);

        netif_device_detach(net);

        cancel_delayed_work_sync(&ndev_ctx->dwork);

        /*
         * Call to the vsc driver to let it know that the device is being
         * removed. Also blocks mtu and channel changes.
         */
        rtnl_lock();
        rndis_filter_device_remove(dev,
                                   rtnl_dereference(ndev_ctx->nvdev));
        rtnl_unlock();

        unregister_netdev(net);

        hv_set_drvdata(dev, NULL);

        free_netdev(net);
        return 0;
}

static const struct hv_vmbus_device_id id_table[] = {
        /* Network guid */
        { HV_NIC_GUID, },
        { },
};

MODULE_DEVICE_TABLE(vmbus, id_table);

/* The one and only one */
static struct  hv_driver netvsc_drv = {
        .name = KBUILD_MODNAME,
        .id_table = id_table,
        .probe = netvsc_probe,
        .remove = netvsc_remove,
};

/*
 * On Hyper-V, every VF interface is matched with a corresponding
 * synthetic interface. The synthetic interface is presented first
 * to the guest. When the corresponding VF instance is registered,
 * we will take care of switching the data path.
 */
static int netvsc_netdev_event(struct notifier_block *this,
                               unsigned long event, void *ptr)
{
        struct net_device *event_dev = netdev_notifier_info_to_dev(ptr);

        /* Skip our own events */
        if (event_dev->netdev_ops == &device_ops)
                return NOTIFY_DONE;

        /* Avoid non-Ethernet type devices */
        if (event_dev->type != ARPHRD_ETHER)
                return NOTIFY_DONE;

        /* Avoid Vlan dev with same MAC registering as VF */
        if (is_vlan_dev(event_dev))
                return NOTIFY_DONE;

        /* Avoid Bonding master dev with same MAC registering as VF */
        if ((event_dev->priv_flags & IFF_BONDING) &&
            (event_dev->flags & IFF_MASTER))
                return NOTIFY_DONE;

        switch (event) {
        case NETDEV_REGISTER:
                return netvsc_register_vf(event_dev);
        case NETDEV_UNREGISTER:
                return netvsc_unregister_vf(event_dev);
        case NETDEV_UP:
                return netvsc_vf_up(event_dev);
        case NETDEV_DOWN:
                return netvsc_vf_down(event_dev);
        default:
                return NOTIFY_DONE;
        }
}

static struct notifier_block netvsc_netdev_notifier = {
        .notifier_call = netvsc_netdev_event,
};

static void __exit netvsc_drv_exit(void)
{
        unregister_netdevice_notifier(&netvsc_netdev_notifier);
        vmbus_driver_unregister(&netvsc_drv);
}

static int __init netvsc_drv_init(void)
{
        int ret;

        if (ring_size < RING_SIZE_MIN) {
                ring_size = RING_SIZE_MIN;
                pr_info("Increased ring_size to %d (min allowed)\n",
                        ring_size);
        }
        ret = vmbus_driver_register(&netvsc_drv);

        if (ret)
                return ret;

        register_netdevice_notifier(&netvsc_netdev_notifier);
        return 0;
}

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Microsoft Hyper-V network driver");

module_init(netvsc_drv_init);
module_exit(netvsc_drv_exit);