[PATCH 4.19 16/57] hv_netvsc: Fix a warning of suspicious RCU usage

Greg Kroah-Hartman
2019-09-08T12:47:13Z

[ Upstream commit 6d0d779dca73cd5acb649c54f81401f93098b298 ]

This fixes a warning of "suspicious rcu_dereference_check() usage"
when nload runs.

Fixes: 776e726bfb34 ("netvsc: fix RCU warning in get_stats")
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/hyperv/netvsc_drv.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index cc60ef9634db2..6f6c0dbd91fc8 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -1248,12 +1248,15 @@ 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);
+ struct netvsc_device *nvdev;
struct netvsc_vf_pcpu_stats vf_tot;
int i;

+ rcu_read_lock();
+
+ nvdev = rcu_dereference(ndev_ctx->nvdev);
if (!nvdev)
- return;
+ goto out;

netdev_stats_to_stats64(t, &net->stats);

@@ -1292,6 +1295,8 @@ static void netvsc_get_stats64(struct net_device *net,
t->rx_packets += packets;
t->multicast += multicast;
}
+out:
+ rcu_read_unlock();
}

static int netvsc_set_mac_addr(struct net_device *ndev, void *p)
--
2.20.1