driver core: have match() callback in struct bus_type take a const *

In the match() callback, the struct device_driver * should not be
changed, so change the function callback to be a const *.  This is one
step of many towards making the driver core safe to have struct
device_driver in read-only memory.

Because the match() callback is in all busses, all busses are modified
to handle this properly.  This does entail switching some container_of()
calls to container_of_const() to properly handle the constant *.

For some busses, like PCI and USB and HV, the const * is cast away in
the match callback as those busses do want to modify those structures at
this point in time (they have a local lock in the driver structure.)
That will have to be changed in the future if they wish to have their
struct device * in read-only-memory.

Cc: Rafael J. Wysocki <rafael@kernel.org>
Reviewed-by: Alex Elder <elder@kernel.org>
Acked-by: Sumit Garg <sumit.garg@linaro.org>
Link: https://lore.kernel.org/r/2024070136-wrongdoer-busily-01e8@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 6 insertions, 6 deletions

diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index 8b9ead76e40e..7e2f10182c0c 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -1375,9 +1375,9 @@ EXPORT_SYMBOL_GPL(mdiobus_c45_modify_changed);
  *   require calling the devices own match function, since different classes
  *   of MDIO devices have different match criteria.
  */
-static int mdio_bus_match(struct device *dev, struct device_driver *drv)
+static int mdio_bus_match(struct device *dev, const struct device_driver *drv)
 {
-	struct mdio_driver *mdiodrv = to_mdio_driver(drv);
+	const struct mdio_driver *mdiodrv = to_mdio_driver(drv);
 	struct mdio_device *mdio = to_mdio_device(dev);
 
 	/* Both the driver and device must type-match */
diff --git a/drivers/net/phy/mdio_device.c b/drivers/net/phy/mdio_device.c
index 73f6539b9e50..e747ee63c665 100644
--- a/drivers/net/phy/mdio_device.c
+++ b/drivers/net/phy/mdio_device.c
@@ -35,10 +35,10 @@ static void mdio_device_release(struct device *dev)
 	kfree(to_mdio_device(dev));
 }
 
-int mdio_device_bus_match(struct device *dev, struct device_driver *drv)
+int mdio_device_bus_match(struct device *dev, const struct device_driver *drv)
 {
 	struct mdio_device *mdiodev = to_mdio_device(dev);
-	struct mdio_driver *mdiodrv = to_mdio_driver(drv);
+	const struct mdio_driver *mdiodrv = to_mdio_driver(drv);
 
 	if (mdiodrv->mdiodrv.flags & MDIO_DEVICE_IS_PHY)
 		return 0;
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 6c6ec9475709..fc63299e4632 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -533,10 +533,10 @@ static int phy_scan_fixups(struct phy_device *phydev)
 	return 0;
 }
 
-static int phy_bus_match(struct device *dev, struct device_driver *drv)
+static int phy_bus_match(struct device *dev, const struct device_driver *drv)
 {
 	struct phy_device *phydev = to_phy_device(dev);
-	struct phy_driver *phydrv = to_phy_driver(drv);
+	const struct phy_driver *phydrv = to_phy_driver(drv);
 	const int num_ids = ARRAY_SIZE(phydev->c45_ids.device_ids);
 	int i;