ethtool: add DEBUG_NTF notification

Send ETHTOOL_MSG_DEBUG_NTF notification message whenever debugging message
mask for a device are modified using ETHTOOL_MSG_DEBUG_SET netlink message
or ETHTOOL_SMSGLVL ioctl request.

The notification message has the same format as reply to DEBUG_GET request.
As with other ethtool notifications, netlink requests only trigger the
notification if the mask is actually changed while ioctl request trigger it
whenever the request results in calling the ethtool_ops handler.
Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/ethtool-netlink.rst

@@ -199,6 +199,7 @@ Kernel to userspace:
   ``ETHTOOL_MSG_LINKMODES_NTF``         link modes notification
   ``ETHTOOL_MSG_LINKSTATE_GET_REPLY``   link state info
   ``ETHTOOL_MSG_DEBUG_GET_REPLY``       debugging settings
+  ``ETHTOOL_MSG_DEBUG_NTF``             debugging settings notification
   ===================================== ================================
 
 ``GET`` requests are sent by userspace applications to retrieve device

include/uapi/linux/ethtool_netlink.h

@@ -38,6 +38,7 @@ enum {
 	ETHTOOL_MSG_LINKMODES_NTF,
 	ETHTOOL_MSG_LINKSTATE_GET_REPLY,
 	ETHTOOL_MSG_DEBUG_GET_REPLY,
+	ETHTOOL_MSG_DEBUG_NTF,
 
 	/* add new constants above here */
 	__ETHTOOL_MSG_KERNEL_CNT,

net/ethtool/debug.c

@@ -123,6 +123,7 @@ int ethnl_set_debug(struct sk_buff *skb, struct genl_info *info)
 		goto out_ops;
 
 	dev->ethtool_ops->set_msglevel(dev, msg_mask);
+	ethtool_notify(dev, ETHTOOL_MSG_DEBUG_NTF, NULL);
 
 out_ops:
 	ethnl_ops_complete(dev);

net/ethtool/ioctl.c

@@ -2545,6 +2545,8 @@ int dev_ethtool(struct net *net, struct ifreq *ifr)
 	case ETHTOOL_SMSGLVL:
 		rc = ethtool_set_value_void(dev, useraddr,
 				       dev->ethtool_ops->set_msglevel);
+		if (!rc)
+			ethtool_notify(dev, ETHTOOL_MSG_DEBUG_NTF, NULL);
 		break;
 	case ETHTOOL_GEEE:
 		rc = ethtool_get_eee(dev, useraddr);

net/ethtool/netlink.c

@@ -524,6 +524,7 @@ static const struct ethnl_request_ops *
 ethnl_default_notify_ops[ETHTOOL_MSG_KERNEL_MAX + 1] = {
 	[ETHTOOL_MSG_LINKINFO_NTF]	= &ethnl_linkinfo_request_ops,
 	[ETHTOOL_MSG_LINKMODES_NTF]	= &ethnl_linkmodes_request_ops,
+	[ETHTOOL_MSG_DEBUG_NTF]		= &ethnl_debug_request_ops,
 };
 
 /* default notification handler */
@@ -607,6 +608,7 @@ typedef void (*ethnl_notify_handler_t)(struct net_device *dev, unsigned int cmd,
 static const ethnl_notify_handler_t ethnl_notify_handlers[] = {
 	[ETHTOOL_MSG_LINKINFO_NTF]	= ethnl_default_notify,
 	[ETHTOOL_MSG_LINKMODES_NTF]	= ethnl_default_notify,
+	[ETHTOOL_MSG_DEBUG_NTF]		= ethnl_default_notify,
 };
 
 void ethtool_notify(struct net_device *dev, unsigned int cmd, const void *data)