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, 5 insertions, 6 deletions

diff --git a/drivers/base/auxiliary.c b/drivers/base/auxiliary.c
index 5832e31bb77b..95408b7594fc 100644
--- a/drivers/base/auxiliary.c
+++ b/drivers/base/auxiliary.c
@@ -177,7 +177,7 @@ static const struct auxiliary_device_id *auxiliary_match_id(const struct auxilia
 	return NULL;
 }
 
-static int auxiliary_match(struct device *dev, struct device_driver *drv)
+static int auxiliary_match(struct device *dev, const struct device_driver *drv)
 {
 	struct auxiliary_device *auxdev = to_auxiliary_dev(dev);
 	const struct auxiliary_driver *auxdrv = to_auxiliary_drv(drv);
diff --git a/drivers/base/base.h b/drivers/base/base.h
index 8bef47afa3a9..0886f555d782 100644
--- a/drivers/base/base.h
+++ b/drivers/base/base.h
@@ -164,8 +164,7 @@ void device_set_deferred_probe_reason(const struct device *dev, struct va_format
 static inline int driver_match_device(const struct device_driver *drv,
 				      struct device *dev)
 {
-	/* cast will be removed in the future when match can handle a const pointer properly. */
-	return drv->bus->match ? drv->bus->match(dev, (struct device_driver *)drv) : 1;
+	return drv->bus->match ? drv->bus->match(dev, drv) : 1;
 }
 
 static inline void dev_sync_state(struct device *dev)
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
index c61ecb0c2ae2..4901fbfca326 100644
--- a/drivers/base/cpu.c
+++ b/drivers/base/cpu.c
@@ -26,7 +26,7 @@
 
 static DEFINE_PER_CPU(struct device *, cpu_sys_devices);
 
-static int cpu_subsys_match(struct device *dev, struct device_driver *drv)
+static int cpu_subsys_match(struct device *dev, const struct device_driver *drv)
 {
 	/* ACPI style match is the only one that may succeed. */
 	if (acpi_driver_match_device(dev, drv))
diff --git a/drivers/base/isa.c b/drivers/base/isa.c
index e23d0b49a793..bfd9215c9070 100644
--- a/drivers/base/isa.c
+++ b/drivers/base/isa.c
@@ -23,7 +23,7 @@ struct isa_dev {
 
 #define to_isa_dev(x) container_of((x), struct isa_dev, dev)
 
-static int isa_bus_match(struct device *dev, struct device_driver *driver)
+static int isa_bus_match(struct device *dev, const struct device_driver *driver)
 {
 	struct isa_driver *isa_driver = to_isa_driver(driver);
 
diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index a6884479f4ac..8a511fe47bdb 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -1332,7 +1332,7 @@ __ATTRIBUTE_GROUPS(platform_dev);
  * and compare it against the name of the driver. Return whether they match
  * or not.
  */
-static int platform_match(struct device *dev, struct device_driver *drv)
+static int platform_match(struct device *dev, const struct device_driver *drv)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct platform_driver *pdrv = to_platform_driver(drv);