Re: [PATCH net,v2] hv_netvsc: Fix VF namespace also in synthetic NIC NETDEV_REGISTER event

On Wed, Oct 16, 2024 at 08:43:57AM -0700, Haiyang Zhang wrote:

The existing code moves VF to the same namespace as the synthetic NIC during netvsc_register_vf(). But, if the synthetic device is moved to a new namespace after the VF registration, the VF won't be moved together.

To make the behavior more consistent, add a namespace check for synthetic NIC's NETDEV_REGISTER event (generated during its move), and move the VF if it is not in the same namespace.

Cc: stable@vger.kernel.org Fixes: c0a41b887ce6 ("hv_netvsc: move VF to same namespace as netvsc device") Suggested-by: Stephen Hemminger stephen@networkplumber.org Signed-off-by: Haiyang Zhang haiyangz@microsoft.com

---

v2: Move my fix to synthetic NIC's NETDEV_REGISTER event as suggested by Stephen.

---

drivers/net/hyperv/netvsc_drv.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+)

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c index 153b97f8ec0d..54e98356ee93 100644 --- a/drivers/net/hyperv/netvsc_drv.c +++ b/drivers/net/hyperv/netvsc_drv.c @@ -2798,6 +2798,30 @@ static struct hv_driver netvsc_drv = { }, }; +/* Set VF's namespace same as the synthetic NIC */ +static void netvsc_event_set_vf_ns(struct net_device *ndev) +{

• struct net_device_context *ndev_ctx = netdev_priv(ndev);
• struct net_device *vf_netdev = rtnl_dereference(ndev_ctx->vf_netdev);
• int ret;

In Networking code it is preferred to arrange local variables in reverse xmas tree order - longest line to shortest.

I believe that could be achieved as follows (completely untested!):

struct net_device_context *ndev_ctx = netdev_priv(ndev); struct net_device *vf_netdev; int ret;

vf_netdev = rtnl_dereference(ndev_ctx->vf_netdev); if (!vf_netdev) return;

With that addressed please feel free to add:

Reviewed-by: Simon Horman horms@kernel.org

• if (!vf_netdev)

• return;
  

• if (!net_eq(dev_net(ndev), dev_net(vf_netdev))) {

• ret = dev_change_net_namespace(vf_netdev, dev_net(ndev),
  

• 			       "eth%d");
  

• if (ret)
  

• 	netdev_err(vf_netdev,
  

• 		   "Cannot move to same namespace as %s: %d\n",
  

• 		   ndev->name, ret);
  

• else
  

• 	netdev_info(vf_netdev,
  

• 		    "Moved VF to namespace with: %s\n",
  

• 		    ndev->name);
  

• }

+}

/*

• On Hyper-V, every VF interface is matched with a corresponding
• synthetic interface. The synthetic interface is presented first

@@ -2810,6 +2834,11 @@ static int netvsc_netdev_event(struct notifier_block *this, struct net_device *event_dev = netdev_notifier_info_to_dev(ptr); int ret = 0;

• if (event_dev->netdev_ops == &device_ops && event == NETDEV_REGISTER) {

• netvsc_event_set_vf_ns(event_dev);
  

• return NOTIFY_DONE;
  

• }
• ret = check_dev_is_matching_vf(event_dev); if (ret != 0) return NOTIFY_DONE;