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 <[email protected]>
Reviewed-by: Alex Elder <[email protected]>
Acked-by: Sumit Garg <[email protected]>
Link: https://lore.kernel.org/r/2024070136-wrongdoer-busily-01e8@gregkh
Signed-off-by: Greg Kroah-Hartman <[email protected]>

1 files changed, 6 insertions, 13 deletions

diff --git a/include/linux/mdio.h b/include/linux/mdio.h
index 68f8d2e970d4..efeca5bd7600 100644
--- a/include/linux/mdio.h
+++ b/include/linux/mdio.h
@@ -31,7 +31,7 @@ struct mdio_device {
 	struct mii_bus *bus;
 	char modalias[MDIO_NAME_SIZE];
 
-	int (*bus_match)(struct device *dev, struct device_driver *drv);
+	int (*bus_match)(struct device *dev, const struct device_driver *drv);
 	void (*device_free)(struct mdio_device *mdiodev);
 	void (*device_remove)(struct mdio_device *mdiodev);
 
@@ -57,11 +57,8 @@ struct mdio_driver_common {
 };
 #define MDIO_DEVICE_FLAG_PHY		1
 
-static inline struct mdio_driver_common *
-to_mdio_common_driver(const struct device_driver *driver)
-{
-	return container_of(driver, struct mdio_driver_common, driver);
-}
+#define to_mdio_common_driver(__drv_c)	container_of_const(__drv_c, struct mdio_driver_common,	\
+							   driver)
 
 /* struct mdio_driver: Generic MDIO driver */
 struct mdio_driver {
@@ -80,12 +77,8 @@ struct mdio_driver {
 	void (*shutdown)(struct mdio_device *mdiodev);
 };
 
-static inline struct mdio_driver *
-to_mdio_driver(const struct device_driver *driver)
-{
-	return container_of(to_mdio_common_driver(driver), struct mdio_driver,
-			    mdiodrv);
-}
+#define to_mdio_driver(__drv_m)	container_of_const(to_mdio_common_driver(__drv_m),	\
+						   struct mdio_driver, mdiodrv)
 
 /* device driver data */
 static inline void mdiodev_set_drvdata(struct mdio_device *mdio, void *data)
@@ -105,7 +98,7 @@ void mdio_device_remove(struct mdio_device *mdiodev);
 void mdio_device_reset(struct mdio_device *mdiodev, int value);
 int mdio_driver_register(struct mdio_driver *drv);
 void mdio_driver_unregister(struct mdio_driver *drv);
-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);
 
 static inline void mdio_device_get(struct mdio_device *mdiodev)
 {