> -----Original Message-----
> From: Shradha Gupta <shradhagupta@xxxxxxxxxxxxxxxxxxx>
> Sent: Tuesday, January 30, 2024 2:19 AM
> To: KY Srinivasan <kys@xxxxxxxxxxxxx>; Haiyang Zhang
> <haiyangz@xxxxxxxxxxxxx>; Wei Liu <wei.liu@xxxxxxxxxx>; Dexuan Cui
> <decui@xxxxxxxxxxxxx>; David S. Miller <davem@xxxxxxxxxxxxx>; Eric
> Dumazet <edumazet@xxxxxxxxxx>; Jakub Kicinski <kuba@xxxxxxxxxx>; Paolo
> Abeni <pabeni@xxxxxxxxxx>; Wojciech Drewek <wojciech.drewek@xxxxxxxxx>;
> linux-hyperv@xxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx
> Cc: Shradha Gupta <shradhagupta@xxxxxxxxxxxxxxxxxxx>; Shradha Gupta
> <shradhagupta@xxxxxxxxxxxxx>; stable@xxxxxxxxxxxxxxx
> Subject: [PATCH] hv_netvsc:Register VF in netvsc_probe if
> NET_DEVICE_REGISTER missed
>
> If hv_netvsc driver is removed and reloaded, the NET_DEVICE_REGISTER
> handler cannot perform VF register successfully as the register call
> is received before netvsc_probe is finished. This is because we
> register register_netdevice_notifier() very early(even before
> vmbus_driver_register()).
> To fix this, we try to register each such matching VF( if it is visible
> as a netdevice) at the end of netvsc_probe.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 85520856466e ("hv_netvsc: Fix race of register_netdevice_notifier
> and VF register")
> Suggested-by: Dexuan Cui <decui@xxxxxxxxxxxxx>
> Signed-off-by: Shradha Gupta <shradhagupta@xxxxxxxxxxxxxxxxxxx>
> Tested-on: Ubuntu22
> Testcases: LISA testsuites
> verify_reload_hyperv_modules, perf_tcp_ntttcp_sriov
> ---
> drivers/net/hyperv/netvsc_drv.c | 49 ++++++++++++++++++++++++++++-----
> 1 file changed, 42 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/net/hyperv/netvsc_drv.c
> b/drivers/net/hyperv/netvsc_drv.c
> index 706ea5263e87..25c4dc9cc4bd 100644
> --- a/drivers/net/hyperv/netvsc_drv.c
> +++ b/drivers/net/hyperv/netvsc_drv.c
> @@ -42,6 +42,10 @@
> #define LINKCHANGE_INT (2 * HZ)
> #define VF_TAKEOVER_INT (HZ / 10)
>
> +/* Macros to define the context of vf registration */
> +#define VF_REG_IN_PROBE 1
> +#define VF_REG_IN_RECV_CBACK 2
> +
> static unsigned int ring_size __ro_after_init = 128;
> module_param(ring_size, uint, 0444);
> MODULE_PARM_DESC(ring_size, "Ring buffer size (# of pages)");
> @@ -2183,7 +2187,7 @@ static rx_handler_result_t
> netvsc_vf_handle_frame(struct sk_buff **pskb)
> }
>
> static int netvsc_vf_join(struct net_device *vf_netdev,
> - struct net_device *ndev)
> + struct net_device *ndev, int context)
> {
> struct net_device_context *ndev_ctx = netdev_priv(ndev);
> int ret;
> @@ -2205,8 +2209,11 @@ static int netvsc_vf_join(struct net_device
> *vf_netdev,
> ndev->name, ret);
> goto upper_link_failed;
> }
> -
> - schedule_delayed_work(&ndev_ctx->vf_takeover, VF_TAKEOVER_INT);
> + /* If this registration is called from probe context vf_takeover
> + * is taken care of later in probe itself.
> + */
> + if (context == VF_REG_IN_RECV_CBACK)
> + schedule_delayed_work(&ndev_ctx->vf_takeover,
> VF_TAKEOVER_INT);
>
> call_netdevice_notifiers(NETDEV_JOIN, vf_netdev);
>
> @@ -2344,7 +2351,7 @@ static int netvsc_prepare_bonding(struct net_device
> *vf_netdev)
> return NOTIFY_DONE;
> }
>
> -static int netvsc_register_vf(struct net_device *vf_netdev)
> +static int netvsc_register_vf(struct net_device *vf_netdev, int context)
> {
> struct net_device_context *net_device_ctx;
> struct netvsc_device *netvsc_dev;
> @@ -2384,7 +2391,7 @@ static int netvsc_register_vf(struct net_device
> *vf_netdev)
>
> netdev_info(ndev, "VF registering: %s\n", vf_netdev->name);
>
> - if (netvsc_vf_join(vf_netdev, ndev) != 0)
> + if (netvsc_vf_join(vf_netdev, ndev, context) != 0)
> return NOTIFY_DONE;
>
> dev_hold(vf_netdev);
> @@ -2485,7 +2492,7 @@ static int netvsc_unregister_vf(struct net_device
> *vf_netdev)
> static int netvsc_probe(struct hv_device *dev,
> const struct hv_vmbus_device_id *dev_id)
> {
> - struct net_device *net = NULL;
> + struct net_device *net = NULL, *vf_netdev;
> struct net_device_context *net_device_ctx;
> struct netvsc_device_info *device_info = NULL;
> struct netvsc_device *nvdev;
> @@ -2597,6 +2604,34 @@ static int netvsc_probe(struct hv_device *dev,
> }
>
> list_add(&net_device_ctx->list, &netvsc_dev_list);
> +
> + /* When the hv_netvsc driver is removed and readded, the
> + * NET_DEVICE_REGISTER for the vf device is replayed before probe
> + * is complete. This is because register_netdevice_notifier() gets
> + * registered before vmbus_driver_register() so that callback func
> + * is set before probe and we don't miss events like
> NETDEV_POST_INIT
> + * So, in this section we try to register each matching
> + * vf device that is present as a netdevice, knowing that it's
> register
> + * call is not processed in the netvsc_netdev_notifier(as probing
> is
> + * progress and get_netvsc_byslot fails).
> + */
> + for_each_netdev(dev_net(net), vf_netdev) {
> + if (vf_netdev->netdev_ops == &device_ops)
> + continue;
> +
> + if (vf_netdev->type != ARPHRD_ETHER)
> + continue;
> +
> + if (is_vlan_dev(vf_netdev))
> + continue;
> +
> + if (netif_is_bond_master(vf_netdev))
> + continue;
> +
> + netvsc_prepare_bonding(vf_netdev);
> + netvsc_register_vf(vf_netdev, VF_REG_IN_PROBE);
> + __netvsc_vf_setup(net, vf_netdev);
> + }
> rtnl_unlock();
>
> netvsc_devinfo_put(device_info);
> @@ -2773,7 +2808,7 @@ static int netvsc_netdev_event(struct
> notifier_block *this,
> case NETDEV_POST_INIT:
> return netvsc_prepare_bonding(event_dev);
> case NETDEV_REGISTER:
> - return netvsc_register_vf(event_dev);
> + return netvsc_register_vf(event_dev, VF_REG_IN_RECV_CBACK);
> case NETDEV_UNREGISTER:
> return netvsc_unregister_vf(event_dev);
> case NETDEV_UP:
> --
> 2.34.1
Please use [PATCH net] on the subject to specify the branch.
Everything else looks fine.
Reviewed-by: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
