ethtool: add RINGS_NTF notification

Send ETHTOOL_MSG_RINGS_NTF notification whenever ring sizes of a network
device are modified using ETHTOOL_MSG_RINGS_SET netlink message or
ETHTOOL_SRINGPARAM ioctl request.
Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/ethtool-netlink.rst

@@ -216,6 +216,7 @@ Kernel to userspace:
   ``ETHTOOL_MSG_PRIVFLAGS_GET_REPLY``   private flags
   ``ETHTOOL_MSG_PRIVFLAGS_NTF``         private flags
   ``ETHTOOL_MSG_RINGS_GET_REPLY``       ring sizes
+  ``ETHTOOL_MSG_RINGS_NTF``             ring sizes
   ===================================== =================================
 
 ``GET`` requests are sent by userspace applications to retrieve device

include/uapi/linux/ethtool_netlink.h

@@ -55,6 +55,7 @@ enum {
 	ETHTOOL_MSG_PRIVFLAGS_GET_REPLY,
 	ETHTOOL_MSG_PRIVFLAGS_NTF,
 	ETHTOOL_MSG_RINGS_GET_REPLY,
+	ETHTOOL_MSG_RINGS_NTF,
 
 	/* add new constants above here */
 	__ETHTOOL_MSG_KERNEL_CNT,

net/ethtool/ioctl.c

@@ -1635,6 +1635,7 @@ static int ethtool_get_ringparam(struct net_device *dev, void __user *useraddr)
 static int ethtool_set_ringparam(struct net_device *dev, void __user *useraddr)
 {
 	struct ethtool_ringparam ringparam, max = { .cmd = ETHTOOL_GRINGPARAM };
+	int ret;
 
 	if (!dev->ethtool_ops->set_ringparam || !dev->ethtool_ops->get_ringparam)
 		return -EOPNOTSUPP;
@@ -1651,7 +1652,10 @@ static int ethtool_set_ringparam(struct net_device *dev, void __user *useraddr)
 	    ringparam.tx_pending > max.tx_max_pending)
 		return -EINVAL;
 
-	return dev->ethtool_ops->set_ringparam(dev, &ringparam);
+	ret = dev->ethtool_ops->set_ringparam(dev, &ringparam);
+	if (!ret)
+		ethtool_notify(dev, ETHTOOL_MSG_RINGS_NTF, NULL);
+	return ret;
 }
 
 static noinline_for_stack int ethtool_get_channels(struct net_device *dev,

net/ethtool/netlink.c

@@ -532,6 +532,7 @@ ethnl_default_notify_ops[ETHTOOL_MSG_KERNEL_MAX + 1] = {
 	[ETHTOOL_MSG_WOL_NTF]		= &ethnl_wol_request_ops,
 	[ETHTOOL_MSG_FEATURES_NTF]	= &ethnl_features_request_ops,
 	[ETHTOOL_MSG_PRIVFLAGS_NTF]	= &ethnl_privflags_request_ops,
+	[ETHTOOL_MSG_RINGS_NTF]		= &ethnl_rings_request_ops,
 };
 
 /* default notification handler */
@@ -619,6 +620,7 @@ static const ethnl_notify_handler_t ethnl_notify_handlers[] = {
 	[ETHTOOL_MSG_WOL_NTF]		= ethnl_default_notify,
 	[ETHTOOL_MSG_FEATURES_NTF]	= ethnl_default_notify,
 	[ETHTOOL_MSG_PRIVFLAGS_NTF]	= ethnl_default_notify,
+	[ETHTOOL_MSG_RINGS_NTF]		= ethnl_default_notify,
 };
 
 void ethtool_notify(struct net_device *dev, unsigned int cmd, const void *data)

net/ethtool/rings.c

@@ -186,6 +186,9 @@ int ethnl_set_rings(struct sk_buff *skb, struct genl_info *info)
 	}
 
 	ret = dev->ethtool_ops->set_ringparam(dev, &ringparam);
+	if (ret < 0)
+		goto out_ops;
+	ethtool_notify(dev, ETHTOOL_MSG_RINGS_NTF, NULL);
 
 out_ops:
 	ethnl_ops_complete(dev);