net: ethtool: copy req_info from SET to NTF

Copy information parsed for SET with .req_parse to NTF handling
and therefore the GET-equivalent that it ends up executing.
This way if the SET was on a sub-object (like RSS context)
the notification will also be appropriately scoped.

Also copy the phy_index, Maxime suggests this will help PLCA
commands generate accurate notifications as well.

Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Tested-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Link: https://patch.msgid.link/20250623231720.3124717-6-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: kuba-moo

net/ethtool/netlink.c

@@ -911,7 +911,7 @@ static int ethnl_default_set_doit(struct sk_buff *skb, struct genl_info *info)
 	swap(dev->cfg, dev->cfg_pending);
 	if (!ret)
 		goto out_ops;
-	ethtool_notify(dev, ops->set_ntf_cmd);
+	ethnl_notify(dev, ops->set_ntf_cmd, req_info);
 
 	ret = 0;
 out_ops:
@@ -950,7 +950,7 @@ ethnl_default_notify_ops[ETHTOOL_MSG_KERNEL_MAX + 1] = {
 
 /* default notification handler */
 static void ethnl_default_notify(struct net_device *dev, unsigned int cmd,
-				 const void *data)
+				 const struct ethnl_req_info *orig_req_info)
 {
 	struct ethnl_reply_data *reply_data;
 	const struct ethnl_request_ops *ops;
@@ -979,6 +979,11 @@ static void ethnl_default_notify(struct net_device *dev, unsigned int cmd,
 
 	req_info->dev = dev;
 	req_info->flags |= ETHTOOL_FLAG_COMPACT_BITSETS;
+	if (orig_req_info) {
+		req_info->phy_index = orig_req_info->phy_index;
+		memcpy(&req_info[1], &orig_req_info[1],
+		       ops->req_info_size - sizeof(*req_info));
+	}
 
 	netdev_ops_assert_locked(dev);
 
@@ -1029,7 +1034,7 @@ static void ethnl_default_notify(struct net_device *dev, unsigned int cmd,
 /* notifications */
 
 typedef void (*ethnl_notify_handler_t)(struct net_device *dev, unsigned int cmd,
-				       const void *data);
+				       const struct ethnl_req_info *req_info);
 
 static const ethnl_notify_handler_t ethnl_notify_handlers[] = {
 	[ETHTOOL_MSG_LINKINFO_NTF]	= ethnl_default_notify,
@@ -1049,15 +1054,16 @@ static const ethnl_notify_handler_t ethnl_notify_handlers[] = {
 	[ETHTOOL_MSG_MM_NTF]		= ethnl_default_notify,
 };
 
-void ethnl_notify(struct net_device *dev, unsigned int cmd, const void *data)
+void ethnl_notify(struct net_device *dev, unsigned int cmd,
+		  const struct ethnl_req_info *req_info)
 {
 	if (unlikely(!ethnl_ok))
 		return;
 	ASSERT_RTNL();
 
 	if (likely(cmd < ARRAY_SIZE(ethnl_notify_handlers) &&
 		   ethnl_notify_handlers[cmd]))
-		ethnl_notify_handlers[cmd](dev, cmd, data);
+		ethnl_notify_handlers[cmd](dev, cmd, req_info);
 	else
 		WARN_ONCE(1, "notification %u not implemented (dev=%s)\n",
 			  cmd, netdev_name(dev));

net/ethtool/netlink.h

@@ -23,7 +23,8 @@ void *ethnl_dump_put(struct sk_buff *skb, struct netlink_callback *cb, u8 cmd);
 void *ethnl_bcastmsg_put(struct sk_buff *skb, u8 cmd);
 void *ethnl_unicast_put(struct sk_buff *skb, u32 portid, u32 seq, u8 cmd);
 int ethnl_multicast(struct sk_buff *skb, struct net_device *dev);
-void ethnl_notify(struct net_device *dev, unsigned int cmd, const void *data);
+void ethnl_notify(struct net_device *dev, unsigned int cmd,
+		  const struct ethnl_req_info *req_info);
 
 /**
  * ethnl_strz_size() - calculate attribute length for fixed size string
@@ -338,6 +339,8 @@ int ethnl_sock_priv_set(struct sk_buff *skb, struct net_device *dev, u32 portid,
  *	header is already filled on entry, the rest up to @repdata_offset
  *	is zero initialized. This callback should only modify type specific
  *	request info by parsed attributes from request message.
+ *	Called for both GET and SET. Information parsed for SET will
+ *	be conveyed to the req_info used during NTF generation.
  * @prepare_data:
  *	Retrieve and prepare data needed to compose a reply message. Calls to
  *	ethtool_ops handlers are limited to this callback. Common reply data