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Date: Wed, 22 Mar 2017 14:51:01 -0700
From: Stephen Hemminger <stephen@...workplumber.org>
To: kys@...rosoft.com, davem@...emloft.net
Cc: netdev@...r.kernel.org, haiyangz@...rosoft.com,
Stephen Hemminger <sthemmin@...rosoft.com>
Subject: [PATCH net-next 5/9] 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@...rosoft.com>
---
drivers/net/hyperv/hyperv_net.h | 3 ---
drivers/net/hyperv/netvsc.c | 4 ----
drivers/net/hyperv/netvsc_drv.c | 34 ++++++++++------------------------
3 files changed, 10 insertions(+), 31 deletions(-)
diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index 0ade21f95d71..907f55960ba8 100644
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -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;
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index ab9118d620ab..1f17d948f9b0 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -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 */
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index d8a70d07eeec..eb7ae79d47bb 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -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);
--
2.11.0
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