[PATCH net-next v4 1/8] ethtool: linkstate: migrate linkstate functions to support multi-PHY setups

[Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>]

Adapt linkstate_get_sqi() and linkstate_get_sqi_max() to take a
phy_device argument directly, enabling support for setups with
multiple PHYs. The previous assumption of a single PHY attached to
a net_device no longer holds.

Use ethnl_req_get_phydev() to identify the appropriate PHY device
for the operation. Update linkstate_prepare_data() and related
logic to accommodate this change, ensuring compatibility with
multi-PHY configurations.

Signed-off-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
---
changes v3:
- s/ETHTOOL_A_PLCA_HEADER/ETHTOOL_A_LINKSTATE_HEADER
---
 net/ethtool/linkstate.c | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/net/ethtool/linkstate.c b/net/ethtool/linkstate.c
index 34d76e87847d..459cfea7652d 100644
--- a/net/ethtool/linkstate.c
+++ b/net/ethtool/linkstate.c
@@ -26,9 +26,8 @@ const struct nla_policy ethnl_linkstate_get_policy[] = {
 		NLA_POLICY_NESTED(ethnl_header_policy_stats),
 };
 
-static int linkstate_get_sqi(struct net_device *dev)
+static int linkstate_get_sqi(struct phy_device *phydev)
 {
-	struct phy_device *phydev = dev->phydev;
 	int ret;
 
 	if (!phydev)
@@ -46,9 +45,8 @@ static int linkstate_get_sqi(struct net_device *dev)
 	return ret;
 }
 
-static int linkstate_get_sqi_max(struct net_device *dev)
+static int linkstate_get_sqi_max(struct phy_device *phydev)
 {
-	struct phy_device *phydev = dev->phydev;
 	int ret;
 
 	if (!phydev)
@@ -100,19 +98,28 @@ static int linkstate_prepare_data(const struct ethnl_req_info *req_base,
 {
 	struct linkstate_reply_data *data = LINKSTATE_REPDATA(reply_base);
 	struct net_device *dev = reply_base->dev;
+	struct nlattr **tb = info->attrs;
+	struct phy_device *phydev;
 	int ret;
 
+	phydev = ethnl_req_get_phydev(req_base, tb[ETHTOOL_A_LINKSTATE_HEADER],
+				      info->extack);
+	if (IS_ERR(phydev)) {
+		ret = PTR_ERR(phydev);
+		goto out;
+	}
+
 	ret = ethnl_ops_begin(dev);
 	if (ret < 0)
 		return ret;
 	data->link = __ethtool_get_link(dev);
 
-	ret = linkstate_get_sqi(dev);
+	ret = linkstate_get_sqi(phydev);
 	if (linkstate_sqi_critical_error(ret))
 		goto out;
 	data->sqi = ret;
 
-	ret = linkstate_get_sqi_max(dev);
+	ret = linkstate_get_sqi_max(phydev);
 	if (linkstate_sqi_critical_error(ret))
 		goto out;
 	data->sqi_max = ret;
@@ -127,9 +134,9 @@ static int linkstate_prepare_data(const struct ethnl_req_info *req_base,
 			   sizeof(data->link_stats) / 8);
 
 	if (req_base->flags & ETHTOOL_FLAG_STATS) {
-		if (dev->phydev)
+		if (phydev)
 			data->link_stats.link_down_events =
-				READ_ONCE(dev->phydev->link_down_events);
+				READ_ONCE(phydev->link_down_events);
 
 		if (dev->ethtool_ops->get_link_ext_stats)
 			dev->ethtool_ops->get_link_ext_stats(dev,
-- 
2.39.5