hv_netvsc: Set VF priv_flags to IFF_NO_ADDRCONF before open to prevent IPv6 addrconf

JIRA: https://issues.redhat.com/browse/RHEL-89855

commit d7501e0
Author: Li Tian <litian@redhat.com>
Date: 2025-07-16 08:26:05 +0800

    hv_netvsc: Set VF priv_flags to IFF_NO_ADDRCONF before open to prevent IPv6 addrconf
    Set an additional flag IFF_NO_ADDRCONF to prevent ipv6 addrconf.

    Commit under Fixes added a new flag change that was not made
    to hv_netvsc resulting in the VF being assinged an IPv6.

    Fixes: 8a321cf ("net: add IFF_NO_ADDRCONF and use it in bonding to prevent ipv6 addrconf")
    Suggested-by: Cathy Avery <cavery@redhat.com>
    Signed-off-by: Li Tian <litian@redhat.com>
    Reviewed-by: Xin Long <lucien.xin@gmail.com>
    Link: https://patch.msgid.link/20250716002607.4927-1-litian@redhat.com
    Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Signed-off-by: Li Tian <litian@redhat.com>

Author: litian1992

drivers/net/hyperv/netvsc_drv.c

@@ -2316,8 +2316,11 @@ static int netvsc_prepare_bonding(struct net_device *vf_netdev)
 	if (!ndev)
 		return NOTIFY_DONE;
 
-	/* set slave flag before open to prevent IPv6 addrconf */
+	/* Set slave flag and no addrconf flag before open
+	 * to prevent IPv6 addrconf.
+	 */
 	vf_netdev->flags |= IFF_SLAVE;
+	vf_netdev->priv_flags |= IFF_NO_ADDRCONF;
 	return NOTIFY_DONE;
 }