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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: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Stephen Hemminger 2016-09-22 16:56:33 -07:00 committed by David S. Miller
parent e8ff40d4bf
commit f207c10d98
2 changed files with 16 additions and 15 deletions
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2
drivers/net/hyperv/hyperv_net.h
View File

@ -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 */

29
drivers/net/hyperv/netvsc_drv.c
View File

@ -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;