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/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;