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>

5 files changed, 8 insertions, 16 deletions

diff --git a/arch/powerpc/include/asm/ps3.h b/arch/powerpc/include/asm/ps3.h
index d13d8fdc3411..987e23a2bd28 100644
--- a/arch/powerpc/include/asm/ps3.h
+++ b/arch/powerpc/include/asm/ps3.h
@@ -390,11 +390,7 @@ int ps3_system_bus_device_register(struct ps3_system_bus_device *dev);
 int ps3_system_bus_driver_register(struct ps3_system_bus_driver *drv);
 void ps3_system_bus_driver_unregister(struct ps3_system_bus_driver *drv);
 
-static inline struct ps3_system_bus_driver *ps3_drv_to_system_bus_drv(
-	struct device_driver *_drv)
-{
-	return container_of(_drv, struct ps3_system_bus_driver, core);
-}
+#define ps3_drv_to_system_bus_drv(_drv) container_of_const(_drv, struct ps3_system_bus_driver, core)
 static inline struct ps3_system_bus_device *ps3_dev_to_system_bus_dev(
 	const struct device *_dev)
 {
diff --git a/arch/powerpc/include/asm/vio.h b/arch/powerpc/include/asm/vio.h
index 6faf2a931755..7c444150c5ad 100644
--- a/arch/powerpc/include/asm/vio.h
+++ b/arch/powerpc/include/asm/vio.h
@@ -156,11 +156,7 @@ static inline int vio_enable_interrupts(struct vio_dev *dev)
 }
 #endif
 
-static inline struct vio_driver *to_vio_driver(struct device_driver *drv)
-{
-	return container_of(drv, struct vio_driver, driver);
-}
-
+#define to_vio_driver(__drv)	container_of_const(__drv, struct vio_driver, driver)
 #define to_vio_dev(__dev)	container_of_const(__dev, struct vio_dev, dev)
 
 #endif /* __KERNEL__ */
diff --git a/arch/powerpc/platforms/ps3/system-bus.c b/arch/powerpc/platforms/ps3/system-bus.c
index 56dc6b29a3e7..b9a7d9bae687 100644
--- a/arch/powerpc/platforms/ps3/system-bus.c
+++ b/arch/powerpc/platforms/ps3/system-bus.c
@@ -333,10 +333,10 @@ int ps3_mmio_region_init(struct ps3_system_bus_device *dev,
 EXPORT_SYMBOL_GPL(ps3_mmio_region_init);
 
 static int ps3_system_bus_match(struct device *_dev,
-	struct device_driver *_drv)
+	const struct device_driver *_drv)
 {
 	int result;
-	struct ps3_system_bus_driver *drv = ps3_drv_to_system_bus_drv(_drv);
+	const struct ps3_system_bus_driver *drv = ps3_drv_to_system_bus_drv(_drv);
 	struct ps3_system_bus_device *dev = ps3_dev_to_system_bus_dev(_dev);
 
 	if (!dev->match_sub_id)
diff --git a/arch/powerpc/platforms/pseries/ibmebus.c b/arch/powerpc/platforms/pseries/ibmebus.c
index b401282727a4..3436b0af795e 100644
--- a/arch/powerpc/platforms/pseries/ibmebus.c
+++ b/arch/powerpc/platforms/pseries/ibmebus.c
@@ -339,7 +339,7 @@ static struct attribute *ibmbus_bus_attrs[] = {
 };
 ATTRIBUTE_GROUPS(ibmbus_bus);
 
-static int ibmebus_bus_bus_match(struct device *dev, struct device_driver *drv)
+static int ibmebus_bus_bus_match(struct device *dev, const struct device_driver *drv)
 {
 	const struct of_device_id *matches = drv->of_match_table;
 
diff --git a/arch/powerpc/platforms/pseries/vio.c b/arch/powerpc/platforms/pseries/vio.c
index 36d1c7d4156b..ac1d2d2c9a88 100644
--- a/arch/powerpc/platforms/pseries/vio.c
+++ b/arch/powerpc/platforms/pseries/vio.c
@@ -1576,10 +1576,10 @@ void vio_unregister_device(struct vio_dev *viodev)
 }
 EXPORT_SYMBOL(vio_unregister_device);
 
-static int vio_bus_match(struct device *dev, struct device_driver *drv)
+static int vio_bus_match(struct device *dev, const struct device_driver *drv)
 {
 	const struct vio_dev *vio_dev = to_vio_dev(dev);
-	struct vio_driver *vio_drv = to_vio_driver(drv);
+	const struct vio_driver *vio_drv = to_vio_driver(drv);
 	const struct vio_device_id *ids = vio_drv->id_table;
 
 	return (ids != NULL) && (vio_match_device(ids, vio_dev) != NULL);
@@ -1689,7 +1689,7 @@ struct vio_dev *vio_find_node(struct device_node *vnode)
 	/* construct the kobject name from the device node */
 	if (of_node_is_type(vnode_parent, "vdevice")) {
 		const __be32 *prop;
-		
+
 		prop = of_get_property(vnode, "reg", NULL);
 		if (!prop)
 			goto out;