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netvsc: uses RCU instead of removal flag 

It is cleaner to use RCU protected pointer (nvdev_ctx->nvdev)
to indicate device is in removed state, rather than having a separate
boolean flag. By using the pointer the context can be checked
by static checkers and dynamic lockdep.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
stephen hemminger 2017-03-22 14:51:01 -07:00 committed by David S. Miller
parent 545a8e79bd
commit a0be450e19
3 changed files with 10 additions and 31 deletions
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3
drivers/net/hyperv/hyperv_net.h
View File

@ -708,9 +708,6 @@ struct net_device_context {
u32 speed;
struct netvsc_ethtool_stats eth_stats;
/* the device is going away */
bool start_remove;
/* State to manage the associated VF interface. */
struct net_device __rcu *vf_netdev;

4
drivers/net/hyperv/netvsc.c
View File

@ -605,7 +605,6 @@ static void netvsc_send_tx_complete(struct netvsc_device *net_device,
{
struct sk_buff *skb = (struct sk_buff *)(unsigned long)desc->trans_id;
struct net_device *ndev = hv_get_drvdata(device);
struct net_device_context *net_device_ctx = netdev_priv(ndev);
struct vmbus_channel *channel = device->channel;
u16 q_idx = 0;
int queue_sends;
@ -639,7 +638,6 @@ static void netvsc_send_tx_complete(struct netvsc_device *net_device,
wake_up(&net_device->wait_drain);
if (netif_tx_queue_stopped(netdev_get_tx_queue(ndev, q_idx)) &&
!net_device_ctx->start_remove &&
(hv_ringbuf_avail_percent(&channel->outbound) > RING_AVAIL_PERCENT_HIWATER ||
queue_sends < 1))
netif_tx_wake_queue(netdev_get_tx_queue(ndev, q_idx));
@ -1326,8 +1324,6 @@ int netvsc_device_add(struct hv_device *device,
/* Writing nvdev pointer unlocks netvsc_send(), make sure chn_table is
* populated.
*/
wmb();
rcu_assign_pointer(net_device_ctx->nvdev, net_device);
/* Connect with the NetVsp */

34
drivers/net/hyperv/netvsc_drv.c
View File

@ -760,7 +760,7 @@ static int netvsc_set_channels(struct net_device *net,
if (count > net->num_tx_queues || count > net->num_rx_queues)
return -EINVAL;
if (net_device_ctx->start_remove || !nvdev || nvdev->destroy)
if (!nvdev || nvdev->destroy)
return -ENODEV;
if (nvdev->nvsp_version < NVSP_PROTOCOL_VERSION_5)
@ -776,7 +776,6 @@ static int netvsc_set_channels(struct net_device *net,
return ret;
}
net_device_ctx->start_remove = true;
rndis_filter_device_remove(dev, nvdev);
ret = netvsc_set_queues(net, dev, count);
@ -785,8 +784,6 @@ static int netvsc_set_channels(struct net_device *net,
else
netvsc_set_queues(net, dev, nvdev->num_chn);
net_device_ctx->start_remove = false;
if (was_running)
ret = netvsc_open(net);
@ -860,7 +857,7 @@ static int netvsc_change_mtu(struct net_device *ndev, int mtu)
bool was_running;
int ret;
if (ndevctx->start_remove || !nvdev || nvdev->destroy)
if (!nvdev || nvdev->destroy)
return -ENODEV;
was_running = netif_running(ndev);
@ -875,7 +872,6 @@ static int netvsc_change_mtu(struct net_device *ndev, int mtu)
device_info.num_chn = nvdev->num_chn;
device_info.max_num_vrss_chns = nvdev->num_chn;
ndevctx->start_remove = true;
rndis_filter_device_remove(hdev, nvdev);
/* 'nvdev' has been freed in rndis_filter_device_remove() ->
@ -888,8 +884,6 @@ static int netvsc_change_mtu(struct net_device *ndev, int mtu)
rndis_filter_device_add(hdev, &device_info);
ndevctx->start_remove = false;
if (was_running)
ret = netvsc_open(ndev);
@ -1245,10 +1239,10 @@ static void netvsc_link_change(struct work_struct *w)
unsigned long flags, next_reconfig, delay;
rtnl_lock();
if (ndev_ctx->start_remove)
net_device = rtnl_dereference(ndev_ctx->nvdev);
if (!net_device)
goto out_unlock;
net_device = rtnl_dereference(ndev_ctx->nvdev);
rdev = net_device->extension;
next_reconfig = ndev_ctx->last_reconfig + LINKCHANGE_INT;
@ -1509,8 +1503,6 @@ static int netvsc_probe(struct hv_device *dev,
hv_set_drvdata(dev, net);
net_device_ctx->start_remove = false;
INIT_DELAYED_WORK(&net_device_ctx->dwork, netvsc_link_change);
INIT_WORK(&net_device_ctx->work, do_set_multicast);
@ -1579,26 +1571,20 @@ static int netvsc_remove(struct hv_device *dev)
ndev_ctx = netdev_priv(net);
/* Avoid racing with netvsc_change_mtu()/netvsc_set_channels()
* removing the device.
*/
rtnl_lock();
ndev_ctx->start_remove = true;
rtnl_unlock();
netif_device_detach(net);
cancel_delayed_work_sync(&ndev_ctx->dwork);
cancel_work_sync(&ndev_ctx->work);
/* Stop outbound asap */
netif_tx_disable(net);
unregister_netdev(net);
/*
* Call to the vsc driver to let it know that the device is being
* removed
* removed. Also blocks mtu and channel changes.
*/
rtnl_lock();
rndis_filter_device_remove(dev, ndev_ctx->nvdev);
rtnl_unlock();
unregister_netdev(net);
hv_set_drvdata(dev, NULL);