net: phy: Fix modular PHYLIB build

After commit c59530d0d5 ("net: Move PHY statistics code into PHY
library helpers") we made net/core/ethtool.c reference symbols which are
part of the library which can be modular. David introduced a temporary
fix with 1ecd6e8ad9 ("phy: Temporary build fix after phylib changes.")
which would prevent such modularity.

This is not desireable of course, so instead, just inline the functions
into include/linux/phy.h to keep both options available.

Fixes: c59530d0d5 ("net: Move PHY statistics code into PHY library helpers")
Fixes: 1ecd6e8ad9 ("phy: Temporary build fix after phylib changes.")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/Kconfig

@@ -9,6 +9,7 @@ menuconfig MDIO_DEVICE
 
 config MDIO_BUS
 	tristate
+	default m if PHYLIB=m
 	default MDIO_DEVICE
 	help
 	  This internal symbol is used for link time dependencies and it
@@ -170,7 +171,7 @@ config PHYLINK
 	  autonegotiation modes.
 
 menuconfig PHYLIB
-	bool "PHY Device support and infrastructure"
+	tristate "PHY Device support and infrastructure"
 	depends on NETDEVICES
 	select MDIO_DEVICE
 	help

drivers/net/phy/phy.c

@@ -1277,51 +1277,3 @@ int phy_ethtool_nway_reset(struct net_device *ndev)
 	return phy_restart_aneg(phydev);
 }
 EXPORT_SYMBOL(phy_ethtool_nway_reset);
-
-int phy_ethtool_get_strings(struct phy_device *phydev, u8 *data)
-{
-	if (!phydev->drv)
-		return -EIO;
-
-	mutex_lock(&phydev->lock);
-	phydev->drv->get_strings(phydev, data);
-	mutex_unlock(&phydev->lock);
-
-	return 0;
-}
-EXPORT_SYMBOL(phy_ethtool_get_strings);
-
-int phy_ethtool_get_sset_count(struct phy_device *phydev)
-{
-	int ret;
-
-	if (!phydev->drv)
-		return -EIO;
-
-	if (phydev->drv->get_sset_count &&
-	    phydev->drv->get_strings &&
-	    phydev->drv->get_stats) {
-		mutex_lock(&phydev->lock);
-		ret = phydev->drv->get_sset_count(phydev);
-		mutex_unlock(&phydev->lock);
-
-		return ret;
-	}
-
-	return -EOPNOTSUPP;
-}
-EXPORT_SYMBOL(phy_ethtool_get_sset_count);
-
-int phy_ethtool_get_stats(struct phy_device *phydev,
-			  struct ethtool_stats *stats, u64 *data)
-{
-	if (!phydev->drv)
-		return -EIO;
-
-	mutex_lock(&phydev->lock);
-	phydev->drv->get_stats(phydev, stats, data);
-	mutex_unlock(&phydev->lock);
-
-	return 0;
-}
-EXPORT_SYMBOL(phy_ethtool_get_stats);

include/linux/phy.h

@@ -1066,28 +1066,54 @@ int phy_ethtool_nway_reset(struct net_device *ndev);
 #if IS_ENABLED(CONFIG_PHYLIB)
 int __init mdio_bus_init(void);
 void mdio_bus_exit(void);
-int phy_ethtool_get_strings(struct phy_device *phydev, u8 *data);
-int phy_ethtool_get_sset_count(struct phy_device *phydev);
-int phy_ethtool_get_stats(struct phy_device *phydev,
-			  struct ethtool_stats *stats, u64 *data);
-#else
-int phy_ethtool_get_strings(struct phy_device *phydev, u8 *data)
-{
-	return -EOPNOTSUPP;
-}
-
-int phy_ethtool_get_sset_count(struct phy_device *phydev)
-{
-	return -EOPNOTSUPP;
-}
-
-int phy_ethtool_get_stats(struct phy_device *phydev,
-			  struct ethtool_stats *stats, u64 *data)
-{
-	return -EOPNOTSUPP;
-}
 #endif
 
+/* Inline function for use within net/core/ethtool.c (built-in) */
+static inline int phy_ethtool_get_strings(struct phy_device *phydev, u8 *data)
+{
+	if (!phydev->drv)
+		return -EIO;
+
+	mutex_lock(&phydev->lock);
+	phydev->drv->get_strings(phydev, data);
+	mutex_unlock(&phydev->lock);
+
+	return 0;
+}
+
+static inline int phy_ethtool_get_sset_count(struct phy_device *phydev)
+{
+	int ret;
+
+	if (!phydev->drv)
+		return -EIO;
+
+	if (phydev->drv->get_sset_count &&
+	    phydev->drv->get_strings &&
+	    phydev->drv->get_stats) {
+		mutex_lock(&phydev->lock);
+		ret = phydev->drv->get_sset_count(phydev);
+		mutex_unlock(&phydev->lock);
+
+		return ret;
+	}
+
+	return -EOPNOTSUPP;
+}
+
+static inline int phy_ethtool_get_stats(struct phy_device *phydev,
+					struct ethtool_stats *stats, u64 *data)
+{
+	if (!phydev->drv)
+		return -EIO;
+
+	mutex_lock(&phydev->lock);
+	phydev->drv->get_stats(phydev, stats, data);
+	mutex_unlock(&phydev->lock);
+
+	return 0;
+}
+
 extern struct bus_type mdio_bus_type;
 
 struct mdio_board_info {