net: phy: constify phydev->drv

Device driver structures are shared between all devices that they
match, and thus nothing should never write to the device driver
structure through the phydev->drv pointer. Let's make this pointer
const to catch code that attempts to do so.
Suggested-by: Christian Marangi <ansuelsmth@gmail.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://lore.kernel.org/r/E1rVxXt-002YqY-9G@rmk-PC.armlinux.org.ukSigned-off-by: Paolo Abeni <pabeni@redhat.com>

drivers/net/phy/phy.c

@@ -1290,7 +1290,6 @@ int phy_disable_interrupts(struct phy_device *phydev)
 static irqreturn_t phy_interrupt(int irq, void *phy_dat)
 {
 	struct phy_device *phydev = phy_dat;
-	struct phy_driver *drv = phydev->drv;
 	irqreturn_t ret;
 
 	/* Wakeup interrupts may occur during a system sleep transition.
@@ -1316,7 +1315,7 @@ static irqreturn_t phy_interrupt(int irq, void *phy_dat)
 	}
 
 	mutex_lock(&phydev->lock);
-	ret = drv->handle_interrupt(phydev);
+	ret = phydev->drv->handle_interrupt(phydev);
 	mutex_unlock(&phydev->lock);
 
 	return ret;

drivers/net/phy/phy_device.c

@@ -1413,7 +1413,7 @@ int phy_sfp_probe(struct phy_device *phydev,
 }
 EXPORT_SYMBOL(phy_sfp_probe);
 
-static bool phy_drv_supports_irq(struct phy_driver *phydrv)
+static bool phy_drv_supports_irq(const struct phy_driver *phydrv)
 {
 	return phydrv->config_intr && phydrv->handle_interrupt;
 }
@@ -1867,7 +1867,7 @@ int phy_suspend(struct phy_device *phydev)
 {
 	struct ethtool_wolinfo wol = { .cmd = ETHTOOL_GWOL };
 	struct net_device *netdev = phydev->attached_dev;
-	struct phy_driver *phydrv = phydev->drv;
+	const struct phy_driver *phydrv = phydev->drv;
 	int ret;
 
 	if (phydev->suspended)
@@ -1892,7 +1892,7 @@ EXPORT_SYMBOL(phy_suspend);
 
 int __phy_resume(struct phy_device *phydev)
 {
-	struct phy_driver *phydrv = phydev->drv;
+	const struct phy_driver *phydrv = phydev->drv;
 	int ret;
 
 	lockdep_assert_held(&phydev->lock);

drivers/net/phy/xilinx_gmii2rgmii.c

@@ -22,7 +22,7 @@
 
 struct gmii2rgmii {
 	struct phy_device *phy_dev;
-	struct phy_driver *phy_drv;
+	const struct phy_driver *phy_drv;
 	struct phy_driver conv_phy_drv;
 	struct mdio_device *mdio;
 };

include/linux/phy.h

@@ -638,7 +638,7 @@ struct phy_device {
 
 	/* Information about the PHY type */
 	/* And management functions */
-	struct phy_driver *drv;
+	const struct phy_driver *drv;
 
 	struct device_link *devlink;