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, 2 insertions, 2 deletions

diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
index 094ee97ea26c..c406b949026f 100644
--- a/drivers/fpga/dfl.c
+++ b/drivers/fpga/dfl.c
@@ -257,10 +257,10 @@ dfl_match_one_device(const struct dfl_device_id *id, struct dfl_device *ddev)
 	return NULL;
 }
 
-static int dfl_bus_match(struct device *dev, struct device_driver *drv)
+static int dfl_bus_match(struct device *dev, const struct device_driver *drv)
 {
 	struct dfl_device *ddev = to_dfl_dev(dev);
-	struct dfl_driver *ddrv = to_dfl_drv(drv);
+	const struct dfl_driver *ddrv = to_dfl_drv(drv);
 	const struct dfl_device_id *id_entry;
 
 	id_entry = ddrv->id_table;