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>

5 files changed, 8 insertions, 8 deletions

diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c
index 781f84901256..53b68f8c32f3 100644
--- a/drivers/s390/cio/css.c
+++ b/drivers/s390/cio/css.c
@@ -1354,10 +1354,10 @@ int sch_is_pseudo_sch(struct subchannel *sch)
 	return sch == to_css(sch->dev.parent)->pseudo_subchannel;
 }
 
-static int css_bus_match(struct device *dev, struct device_driver *drv)
+static int css_bus_match(struct device *dev, const struct device_driver *drv)
 {
 	struct subchannel *sch = to_subchannel(dev);
-	struct css_driver *driver = to_cssdriver(drv);
+	const struct css_driver *driver = to_cssdriver(drv);
 	struct css_device_id *id;
 
 	/* When driver_override is set, only bind to the matching driver */
diff --git a/drivers/s390/cio/css.h b/drivers/s390/cio/css.h
index c2b175592bb7..a65a27dc520c 100644
--- a/drivers/s390/cio/css.h
+++ b/drivers/s390/cio/css.h
@@ -103,7 +103,7 @@ struct css_driver {
 	int (*settle)(void);
 };
 
-#define to_cssdriver(n) container_of(n, struct css_driver, drv)
+#define to_cssdriver(n) container_of_const(n, struct css_driver, drv)
 
 extern int css_driver_register(struct css_driver *);
 extern void css_driver_unregister(struct css_driver *);
diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c
index 920f550bc313..b0f23242e171 100644
--- a/drivers/s390/cio/device.c
+++ b/drivers/s390/cio/device.c
@@ -58,10 +58,10 @@ static const struct bus_type ccw_bus_type;
  * subsystem driver and one channel system per machine, but
  * we still use the abstraction. T.R. says it's a good idea. */
 static int
-ccw_bus_match (struct device * dev, struct device_driver * drv)
+ccw_bus_match (struct device * dev, const struct device_driver * drv)
 {
 	struct ccw_device *cdev = to_ccwdev(dev);
-	struct ccw_driver *cdrv = to_ccwdrv(drv);
+	const struct ccw_driver *cdrv = to_ccwdrv(drv);
 	const struct ccw_device_id *ids = cdrv->ids, *found;
 
 	if (!ids)
diff --git a/drivers/s390/crypto/ap_bus.c b/drivers/s390/crypto/ap_bus.c
index 898865be0dad..0998b17ecb37 100644
--- a/drivers/s390/crypto/ap_bus.c
+++ b/drivers/s390/crypto/ap_bus.c
@@ -552,9 +552,9 @@ static void ap_poll_thread_stop(void)
  *
  * AP bus driver registration/unregistration.
  */
-static int ap_bus_match(struct device *dev, struct device_driver *drv)
+static int ap_bus_match(struct device *dev, const struct device_driver *drv)
 {
-	struct ap_driver *ap_drv = to_ap_drv(drv);
+	const struct ap_driver *ap_drv = to_ap_drv(drv);
 	struct ap_device_id *id;
 
 	/*
diff --git a/drivers/s390/crypto/ap_bus.h b/drivers/s390/crypto/ap_bus.h
index fdbc6fdfdf57..0b275c719319 100644
--- a/drivers/s390/crypto/ap_bus.h
+++ b/drivers/s390/crypto/ap_bus.h
@@ -158,7 +158,7 @@ struct ap_driver {
 				 struct ap_config_info *old_config_info);
 };
 
-#define to_ap_drv(x) container_of((x), struct ap_driver, driver)
+#define to_ap_drv(x) container_of_const((x), struct ap_driver, driver)
 
 int ap_driver_register(struct ap_driver *, struct module *, char *);
 void ap_driver_unregister(struct ap_driver *);