Re: [PATCH net-next 2/8] netvsc: add some rtnl_dereference annotations

[kbuild test robot]

Hi Stephen,

[auto build test ERROR on net-next/master]

url:
https://github.com/0day-ci/linux/commits/Stephen-Hemminger/netvsc-lockdep-and-related-fixes/20170720-191938
config: x86_64-rhel (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
# save the attached .config to linux build tree
make ARCH=x86_64 

Note: the 
linux-review/Stephen-Hemminger/netvsc-lockdep-and-related-fixes/20170720-191938 
HEAD a5e48342eae178e9ed020d3634cdf92f1f05cb70 builds fine.
  It only hurts bisectibility.

All error/warnings (new ones prefixed by >>):

   drivers/net/hyperv/netvsc.c: In function 'netvsc_switch_datapath':
>> drivers/net/hyperv/netvsc.c:44:33: error: implicit declaration of function 
>> 'rtnl_dereference' [-Werror=implicit-function-declaration]
 struct netvsc_device *nv_dev = rtnl_dereference(net_device_ctx->nvdev);
^~~~
>> drivers/net/hyperv/netvsc.c:44:33: warning: initialization makes pointer 
>> from integer without a cast [-Wint-conversion]
   drivers/net/hyperv/netvsc.c: In function 'netvsc_device_remove':
   drivers/net/hyperv/netvsc.c:553:5: warning: initialization makes pointer 
from integer without a cast [-Wint-conversion]
  = rtnl_dereference(net_device_ctx->nvdev);
^~~~
   cc1: some warnings being treated as errors

vim +/rtnl_dereference +44 drivers/net/hyperv/netvsc.c

35  
36  /*
37   * Switch the data path from the synthetic interface to the VF
38   * interface.
39   */
40  void netvsc_switch_datapath(struct net_device *ndev, bool vf)
41  {
42  struct net_device_context *net_device_ctx = netdev_priv(ndev);
43  struct hv_device *dev = net_device_ctx->device_ctx;
  > 44  struct netvsc_device *nv_dev = 
rtnl_dereference(net_device_ctx->nvdev);
45  struct nvsp_message *init_pkt = _dev->channel_init_pkt;
46  
47  memset(init_pkt, 0, sizeof(struct nvsp_message));
48  init_pkt->hdr.msg_type = NVSP_MSG4_TYPE_SWITCH_DATA_PATH;
49  if (vf)
50  init_pkt->msg.v4_msg.active_dp.active_datapath =
51  NVSP_DATAPATH_VF;
52  else
53  init_pkt->msg.v4_msg.active_dp.active_datapath =
54  NVSP_DATAPATH_SYNTHETIC;
55  
56  vmbus_sendpacket(dev->channel, init_pkt,
57 sizeof(struct nvsp_message),
58 (unsigned long)init_pkt,
59 VM_PKT_DATA_INBAND, 0);
60  
61  net_device_ctx->datapath = vf;
62  }
63  

---
0-DAY kernel test infrastructureOpen Source Technology Center
https://lists.01.org/pipermail/kbuild-all   Intel Corporation


.config.gz
Description: application/gzip

[PATCH net-next 2/8] netvsc: add some rtnl_dereference annotations

[Stephen Hemminger]

In a couple places RTNL is held, and the netvsc_device pointer
is acquired without annotation.

Signed-off-by: Stephen Hemminger 
---
 drivers/net/hyperv/netvsc.c | 5 +++--
 drivers/net/hyperv/netvsc_drv.c | 7 ---
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 0a9167dd72fb..e202ec5d6f63 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -41,7 +41,7 @@ void netvsc_switch_datapath(struct net_device *ndev, bool vf)
 {
struct net_device_context *net_device_ctx = netdev_priv(ndev);
struct hv_device *dev = net_device_ctx->device_ctx;
-   struct netvsc_device *nv_dev = net_device_ctx->nvdev;
+   struct netvsc_device *nv_dev = rtnl_dereference(net_device_ctx->nvdev);
struct nvsp_message *init_pkt = _dev->channel_init_pkt;
 
memset(init_pkt, 0, sizeof(struct nvsp_message));
@@ -549,7 +549,8 @@ void netvsc_device_remove(struct hv_device *device)
 {
struct net_device *ndev = hv_get_drvdata(device);
struct net_device_context *net_device_ctx = netdev_priv(ndev);
-   struct netvsc_device *net_device = net_device_ctx->nvdev;
+   struct netvsc_device *net_device
+   = rtnl_dereference(net_device_ctx->nvdev);
int i;
 
netvsc_disconnect_vsp(device);
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 09b07ca9e69a..e8e82a6a4b1a 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -69,7 +69,7 @@ static void netvsc_set_multicast_list(struct net_device *net)
 static int netvsc_open(struct net_device *net)
 {
struct net_device_context *ndev_ctx = netdev_priv(net);
-   struct netvsc_device *nvdev = ndev_ctx->nvdev;
+   struct netvsc_device *nvdev = rtnl_dereference(ndev_ctx->nvdev);
struct rndis_device *rdev;
int ret = 0;
 
@@ -1364,7 +1364,7 @@ static struct net_device *get_netvsc_byref(struct 
net_device *vf_netdev)
continue;   /* not a netvsc device */
 
net_device_ctx = netdev_priv(dev);
-   if (net_device_ctx->nvdev == NULL)
+   if (!rtnl_dereference(net_device_ctx->nvdev))
continue;   /* device is removed */
 
if (rtnl_dereference(net_device_ctx->vf_netdev) == vf_netdev)
@@ -1589,7 +1589,8 @@ static int netvsc_remove(struct hv_device *dev)
 * removed. Also blocks mtu and channel changes.
 */
rtnl_lock();
-   rndis_filter_device_remove(dev, ndev_ctx->nvdev);
+   rndis_filter_device_remove(dev,
+  rtnl_dereference(ndev_ctx->nvdev));
rtnl_unlock();
 
unregister_netdev(net);
-- 
2.11.0