From: Stephen Hemminger <stephen@networkplumber.org>
Date: Tue, 27 Mar 2018 11:28:48 -0700
Patch-mainline: v4.16
Subject: hv_netvsc: enable multicast if necessary
Git-commit: f03dbb06dc380274e351ca4b1ee1587ed4529e62
References: fate#323887

My recent change to netvsc drive in how receive flags are handled
broke multicast.  The Hyper-v/Azure virtual interface there is not a
multicast filter list, filtering is only all or none. The driver must
enable all multicast if any multicast address is present.

Fixes: 009f766ca238 ("hv_netvsc: filter multicast/broadcast")
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Olaf Hering <ohering@suse.de>
---
 drivers/net/hyperv/rndis_filter.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/hyperv/rndis_filter.c
+++ b/drivers/net/hyperv/rndis_filter.c
@@ -858,7 +858,7 @@ static void rndis_set_multicast(struct work_struct *w)
 	if (flags & IFF_PROMISC) {
 		filter = NDIS_PACKET_TYPE_PROMISCUOUS;
 	} else {
-		if (flags & IFF_ALLMULTI)
+		if (!netdev_mc_empty(rdev->ndev) || (flags & IFF_ALLMULTI))
 			filter |= NDIS_PACKET_TYPE_ALL_MULTICAST;
 		if (flags & IFF_BROADCAST)
 			filter |= NDIS_PACKET_TYPE_BROADCAST;