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Commit f207c10d authored by Stephen Hemminger's avatar Stephen Hemminger Committed by David S. Miller
Browse files

hv_netvsc: use RCU to protect vf_netdev 



The vf_netdev pointer in the netvsc device context can simply be protected
by RCU because network device destruction is already RCU synchronized.

Signed-off-by: default avatarStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e8ff40d4

drivers/net/hyperv/hyperv_net.h

+1 −1
Original line number Diff line number Diff line
@@ -695,7 +695,7 @@ struct net_device_context { 
	bool start_remove;



	/* State to manage the associated VF interface. */

	struct net_device *vf_netdev;

	struct net_device __rcu *vf_netdev;

	bool vf_inject;

	atomic_t vf_use_cnt;

	/* 1: allocated, serial number is valid. 0: not allocated */

drivers/net/hyperv/netvsc_drv.c

+15 −14
Original line number Diff line number Diff line
@@ -667,8 +667,8 @@ int netvsc_recv_callback(struct hv_device *device_obj, 
{

	struct net_device *net = hv_get_drvdata(device_obj);

	struct net_device_context *net_device_ctx = netdev_priv(net);

	struct net_device *vf_netdev;

	struct sk_buff *skb;

	struct sk_buff *vf_skb;

	struct netvsc_stats *rx_stats;

	u32 bytes_recvd = packet->total_data_buflen;

	int ret = 0;
@@ -676,9 +676,12 @@ int netvsc_recv_callback(struct hv_device *device_obj, 
	if (!net || net->reg_state != NETREG_REGISTERED)

		return NVSP_STAT_FAIL;



	if (READ_ONCE(net_device_ctx->vf_inject)) {

	vf_netdev = rcu_dereference(net_device_ctx->vf_netdev);

	if (vf_netdev) {

		struct sk_buff *vf_skb;



		atomic_inc(&net_device_ctx->vf_use_cnt);

		if (!READ_ONCE(net_device_ctx->vf_inject)) {

		if (!net_device_ctx->vf_inject) {

			/*

			 * We raced; just move on.

			 */
@@ -694,13 +697,12 @@ int netvsc_recv_callback(struct hv_device *device_obj, 
		 * the host). Deliver these via the VF interface

		 * in the guest.

		 */

		vf_skb = netvsc_alloc_recv_skb(net_device_ctx->vf_netdev,

		vf_skb = netvsc_alloc_recv_skb(vf_netdev,

					       packet, csum_info, *data,

					       vlan_tci);

		if (vf_skb != NULL) {

			++net_device_ctx->vf_netdev->stats.rx_packets;

			net_device_ctx->vf_netdev->stats.rx_bytes +=

				bytes_recvd;

			++vf_netdev->stats.rx_packets;

			vf_netdev->stats.rx_bytes += bytes_recvd;

			netif_receive_skb(vf_skb);

		} else {

			++net->stats.rx_dropped;
@@ -1232,7 +1234,7 @@ static struct net_device *get_netvsc_bymac(const u8 *mac) 
	return NULL;

}



static struct net_device *get_netvsc_byref(const struct net_device *vf_netdev)

static struct net_device *get_netvsc_byref(struct net_device *vf_netdev)

{

	struct net_device *dev;
@@ -1248,7 +1250,7 @@ static struct net_device *get_netvsc_byref(const struct net_device *vf_netdev) 
		if (net_device_ctx->nvdev == NULL)

			continue;	/* device is removed */



		if (net_device_ctx->vf_netdev == vf_netdev)

		if (rtnl_dereference(net_device_ctx->vf_netdev) == vf_netdev)

			return dev;	/* a match */

	}
@@ -1275,7 +1277,7 @@ static int netvsc_register_vf(struct net_device *vf_netdev) 


	net_device_ctx = netdev_priv(ndev);

	netvsc_dev = net_device_ctx->nvdev;

	if (!netvsc_dev || net_device_ctx->vf_netdev)

	if (!netvsc_dev || rtnl_dereference(net_device_ctx->vf_netdev))

		return NOTIFY_DONE;



	netdev_info(ndev, "VF registering: %s\n", vf_netdev->name);
@@ -1285,7 +1287,7 @@ static int netvsc_register_vf(struct net_device *vf_netdev) 
	try_module_get(THIS_MODULE);



	dev_hold(vf_netdev);

	net_device_ctx->vf_netdev = vf_netdev;

	rcu_assign_pointer(net_device_ctx->vf_netdev, vf_netdev);

	return NOTIFY_OK;

}
@@ -1379,7 +1381,8 @@ static int netvsc_unregister_vf(struct net_device *vf_netdev) 


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

	netvsc_inject_disable(net_device_ctx);

	net_device_ctx->vf_netdev = NULL;



	RCU_INIT_POINTER(net_device_ctx->vf_netdev, NULL);

	dev_put(vf_netdev);

	module_put(THIS_MODULE);

	return NOTIFY_OK;
@@ -1433,8 +1436,6 @@ static int netvsc_probe(struct hv_device *dev, 
	INIT_LIST_HEAD(&net_device_ctx->reconfig_events);



	atomic_set(&net_device_ctx->vf_use_cnt, 0);

	net_device_ctx->vf_netdev = NULL;

	net_device_ctx->vf_inject = false;



	net->netdev_ops = &device_ops;