Subject: [PATCH] hv_netvsc: Set device flags for properly indicating bonding

From: [email-masked]
Date: Wed, 27 Nov 2024 11:42:50 -0800

From: Long Li <[email-masked]>

hv_netvsc uses a subset of bonding features in that the master always
has only one active slave. But it never properly setup those flags.

Other kernel APIs (e.g those in "include/linux/netdevice.h") check for
IFF_MASTER, IFF_SLAVE and IFF_BONDING for determing if those are used
in a master/slave setup. RDMA uses those APIs extensively when looking
for master/slave devices.

Make hv_netvsc properly setup those flags.

Signed-off-by: Long Li <[email-masked]>
---
 drivers/net/hyperv/netvsc_drv.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index d6c4abfc3a28..2112fb74eb21 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -2204,6 +2204,10 @@ static int netvsc_vf_join(struct net_device *vf_netdev,
 		goto rx_handler_failed;
 	}
 
+	vf_netdev->priv_flags |= IFF_BONDING;
+	ndev->priv_flags |= IFF_BONDING;
+	ndev->flags |= IFF_MASTER;
+
 	ret = netdev_master_upper_dev_link(vf_netdev, ndev,
 					   NULL, NULL, NULL);
 	if (ret != 0) {
@@ -2484,7 +2488,15 @@ static int netvsc_unregister_vf(struct net_device *vf_netdev)
 
 	reinit_completion(&net_device_ctx->vf_add);
 	netdev_rx_handler_unregister(vf_netdev);
+
+	/* Unlink the slave device and clear flag */
+	vf_netdev->priv_flags &= ~IFF_BONDING;
+	ndev->priv_flags &= ~IFF_BONDING;
+	vf_netdev->flags &= ~IFF_SLAVE;
+	ndev->flags &= ~IFF_MASTER;
+
 	netdev_upper_dev_unlink(vf_netdev, ndev);
+
 	RCU_INIT_POINTER(net_device_ctx->vf_netdev, NULL);
 	dev_put(vf_netdev);
 
-- 
2.34.1