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>

2 files changed, 2 insertions, 5 deletions

diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
index 887ed6e358fb..cb730050d3d4 100644
--- a/drivers/cxl/core/port.c
+++ b/drivers/cxl/core/port.c
@@ -2082,7 +2082,7 @@ static int cxl_bus_uevent(const struct device *dev, struct kobj_uevent_env *env)
 			      cxl_device_id(dev));
 }
 
-static int cxl_bus_match(struct device *dev, struct device_driver *drv)
+static int cxl_bus_match(struct device *dev, const struct device_driver *drv)
 {
 	return cxl_device_id(dev) == to_cxl_drv(drv)->id;
 }
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index 603c0120cff8..65c91e133e26 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -823,10 +823,7 @@ struct cxl_driver {
 	int id;
 };
 
-static inline struct cxl_driver *to_cxl_drv(struct device_driver *drv)
-{
-	return container_of(drv, struct cxl_driver, drv);
-}
+#define to_cxl_drv(__drv)	container_of_const(__drv, struct cxl_driver, drv)
 
 int __cxl_driver_register(struct cxl_driver *cxl_drv, struct module *owner,
 			  const char *modname);