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, 1 insertions, 4 deletions

diff --git a/include/sound/ac97/codec.h b/include/sound/ac97/codec.h
index 2fc641cb1982..882b849b9255 100644
--- a/include/sound/ac97/codec.h
+++ b/include/sound/ac97/codec.h
@@ -73,10 +73,7 @@ static inline struct ac97_codec_device *to_ac97_device(struct device *d)
 	return container_of(d, struct ac97_codec_device, dev);
 }
 
-static inline struct ac97_codec_driver *to_ac97_driver(struct device_driver *d)
-{
-	return container_of(d, struct ac97_codec_driver, driver);
-}
+#define to_ac97_driver(__drv) container_of_const(__drv, struct ac97_codec_driver, driver)
 
 #if IS_ENABLED(CONFIG_AC97_BUS_NEW)
 int snd_ac97_codec_driver_register(struct ac97_codec_driver *drv);