ethtool: add CHANNELS_NTF notification

Send ETHTOOL_MSG_CHANNELS_NTF notification whenever channel counts of
a network device are modified using ETHTOOL_MSG_CHANNELS_SET netlink
message or ETHTOOL_SCHANNELS ioctl request.

Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ethtool/channels.c b/net/ethtool/channels.c
index ee232c1..8dc5485 100644
--- a/net/ethtool/channels.c
+++ b/net/ethtool/channels.c
@@ -213,6 +213,9 @@ int ethnl_set_channels(struct sk_buff *skb, struct genl_info *info)
 		}
 
 	ret = dev->ethtool_ops->set_channels(dev, &channels);
+	if (ret < 0)
+		goto out_ops;
+	ethtool_notify(dev, ETHTOOL_MSG_CHANNELS_NTF, NULL);
 
 out_ops:
 	ethnl_ops_complete(dev);
diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index 06224a0..258840b 100644
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -1649,6 +1649,7 @@ static noinline_for_stack int ethtool_set_channels(struct net_device *dev,
 	u16 from_channel, to_channel;
 	u32 max_rx_in_use = 0;
 	unsigned int i;
+	int ret;
 
 	if (!dev->ethtool_ops->set_channels || !dev->ethtool_ops->get_channels)
 		return -EOPNOTSUPP;
@@ -1680,7 +1681,10 @@ static noinline_for_stack int ethtool_set_channels(struct net_device *dev,
 		if (xdp_get_umem_from_qid(dev, i))
 			return -EINVAL;
 
-	return dev->ethtool_ops->set_channels(dev, &channels);
+	ret = dev->ethtool_ops->set_channels(dev, &channels);
+	if (!ret)
+		ethtool_notify(dev, ETHTOOL_MSG_CHANNELS_NTF, NULL);
+	return ret;
 }
 
 static int ethtool_get_pauseparam(struct net_device *dev, void __user *useraddr)
diff --git a/net/ethtool/netlink.c b/net/ethtool/netlink.c
index f61654b..55c8ce4 100644
--- a/net/ethtool/netlink.c
+++ b/net/ethtool/netlink.c
@@ -534,6 +534,7 @@ ethnl_default_notify_ops[ETHTOOL_MSG_KERNEL_MAX + 1] = {
 	[ETHTOOL_MSG_FEATURES_NTF]	= &ethnl_features_request_ops,
 	[ETHTOOL_MSG_PRIVFLAGS_NTF]	= &ethnl_privflags_request_ops,
 	[ETHTOOL_MSG_RINGS_NTF]		= &ethnl_rings_request_ops,
+	[ETHTOOL_MSG_CHANNELS_NTF]	= &ethnl_channels_request_ops,
 };
 
 /* default notification handler */
@@ -622,6 +623,7 @@ static const ethnl_notify_handler_t ethnl_notify_handlers[] = {
 	[ETHTOOL_MSG_FEATURES_NTF]	= ethnl_default_notify,
 	[ETHTOOL_MSG_PRIVFLAGS_NTF]	= ethnl_default_notify,
 	[ETHTOOL_MSG_RINGS_NTF]		= ethnl_default_notify,
+	[ETHTOOL_MSG_CHANNELS_NTF]	= ethnl_default_notify,
 };
 
 void ethtool_notify(struct net_device *dev, unsigned int cmd, const void *data)