ethtool: add COALESCE_NTF notification

Send ETHTOOL_MSG_COALESCE_NTF notification whenever coalescing parameters
of a network device are modified using ETHTOOL_MSG_COALESCE_SET netlink
message or ETHTOOL_SCOALESCE ioctl request.
Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/ethtool-netlink.rst

@@ -224,6 +224,7 @@ Kernel to userspace:
   ``ETHTOOL_MSG_CHANNELS_GET_REPLY``    channel counts
   ``ETHTOOL_MSG_CHANNELS_NTF``          channel counts
   ``ETHTOOL_MSG_COALESCE_GET_REPLY``    coalescing parameters
+  ``ETHTOOL_MSG_COALESCE_NTF``          coalescing parameters
   ===================================== =================================
 
 ``GET`` requests are sent by userspace applications to retrieve device

include/uapi/linux/ethtool_netlink.h

@@ -63,6 +63,7 @@ enum {
 	ETHTOOL_MSG_CHANNELS_GET_REPLY,
 	ETHTOOL_MSG_CHANNELS_NTF,
 	ETHTOOL_MSG_COALESCE_GET_REPLY,
+	ETHTOOL_MSG_COALESCE_NTF,
 
 	/* add new constants above here */
 	__ETHTOOL_MSG_KERNEL_CNT,

net/ethtool/coalesce.c

@@ -339,6 +339,9 @@ int ethnl_set_coalesce(struct sk_buff *skb, struct genl_info *info)
 		goto out_ops;
 
 	ret = dev->ethtool_ops->set_coalesce(dev, &coalesce);
+	if (ret < 0)
+		goto out_ops;
+	ethtool_notify(dev, ETHTOOL_MSG_COALESCE_NTF, NULL);
 
 out_ops:
 	ethnl_ops_complete(dev);

net/ethtool/ioctl.c

@@ -1571,6 +1571,7 @@ static noinline_for_stack int ethtool_set_coalesce(struct net_device *dev,
 						   void __user *useraddr)
 {
 	struct ethtool_coalesce coalesce;
+	int ret;
 
 	if (!dev->ethtool_ops->set_coalesce)
 		return -EOPNOTSUPP;
@@ -1581,7 +1582,10 @@ static noinline_for_stack int ethtool_set_coalesce(struct net_device *dev,
 	if (!ethtool_set_coalesce_supported(dev, &coalesce))
 		return -EOPNOTSUPP;
 
-	return dev->ethtool_ops->set_coalesce(dev, &coalesce);
+	ret = dev->ethtool_ops->set_coalesce(dev, &coalesce);
+	if (!ret)
+		ethtool_notify(dev, ETHTOOL_MSG_COALESCE_NTF, NULL);
+	return ret;
 }
 
 static int ethtool_get_ringparam(struct net_device *dev, void __user *useraddr)

net/ethtool/netlink.c

@@ -544,6 +544,7 @@ ethnl_default_notify_ops[ETHTOOL_MSG_KERNEL_MAX + 1] = {
 	[ETHTOOL_MSG_PRIVFLAGS_NTF]	= &ethnl_privflags_request_ops,
 	[ETHTOOL_MSG_RINGS_NTF]		= &ethnl_rings_request_ops,
 	[ETHTOOL_MSG_CHANNELS_NTF]	= &ethnl_channels_request_ops,
+	[ETHTOOL_MSG_COALESCE_NTF]	= &ethnl_coalesce_request_ops,
 };
 
 /* default notification handler */
@@ -633,6 +634,7 @@ static const ethnl_notify_handler_t ethnl_notify_handlers[] = {
 	[ETHTOOL_MSG_PRIVFLAGS_NTF]	= ethnl_default_notify,
 	[ETHTOOL_MSG_RINGS_NTF]		= ethnl_default_notify,
 	[ETHTOOL_MSG_CHANNELS_NTF]	= ethnl_default_notify,
+	[ETHTOOL_MSG_COALESCE_NTF]	= ethnl_default_notify,
 };
 
 void ethtool_notify(struct net_device *dev, unsigned int cmd, const void *data)