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>

1 files changed, 3 insertions, 3 deletions

diff --git a/drivers/dma/idxd/bus.c b/drivers/dma/idxd/bus.c
index b83b27e04f2a..e647a684485d 100644
--- a/drivers/dma/idxd/bus.c
+++ b/drivers/dma/idxd/bus.c
@@ -33,10 +33,10 @@ void idxd_driver_unregister(struct idxd_device_driver *idxd_drv)
 EXPORT_SYMBOL_GPL(idxd_driver_unregister);
 
 static int idxd_config_bus_match(struct device *dev,
-				 struct device_driver *drv)
+				 const struct device_driver *drv)
 {
-	struct idxd_device_driver *idxd_drv =
-		container_of(drv, struct idxd_device_driver, drv);
+	const struct idxd_device_driver *idxd_drv =
+		container_of_const(drv, struct idxd_device_driver, drv);
 	struct idxd_dev *idxd_dev = confdev_to_idxd_dev(dev);
 	int i = 0;