driver core: make [device_]driver_attach take a const *

Change device_driver_attach() and driver_attach() to take a const * to
struct device driver as neither of them modify the structure at all.

Also, for some odd reason, drivers/dma/idxd/compat.c had a duplicate
external reference to device_driver_attach(), so remove that to fix up
the build, it should never have had that there in the first place.

Cc: Rafael J. Wysocki <rafael@kernel.org>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Vinod Koul <vkoul@kernel.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Petr Tesarik <petr.tesarik.ext@huawei.com>
Cc: Alexander Lobakin <aleksander.lobakin@intel.com>
Cc: dmaengine@vger.kernel.org
Link: https://lore.kernel.org/r/2024061401-rasping-manger-c385@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/base/base.h

@@ -161,10 +161,11 @@ void device_release_driver_internal(struct device *dev, const struct device_driv
 void driver_detach(const struct device_driver *drv);
 void driver_deferred_probe_del(struct device *dev);
 void device_set_deferred_probe_reason(const struct device *dev, struct va_format *vaf);
-static inline int driver_match_device(struct device_driver *drv,
+static inline int driver_match_device(const struct device_driver *drv,
 				      struct device *dev)
 {
-	return drv->bus->match ? drv->bus->match(dev, drv) : 1;
+	/* cast will be removed in the future when match can handle a const pointer properly. */
+	return drv->bus->match ? drv->bus->match(dev, (struct device_driver *)drv) : 1;
 }
 
 static inline void dev_sync_state(struct device *dev)

drivers/base/dd.c

@@ -1118,7 +1118,7 @@ static void __device_driver_unlock(struct device *dev, struct device *parent)
  * Manually attach driver to a device. Will acquire both @dev lock and
  * @dev->parent lock if needed. Returns 0 on success, -ERR on failure.
  */
-int device_driver_attach(struct device_driver *drv, struct device *dev)
+int device_driver_attach(const struct device_driver *drv, struct device *dev)
 {
 	int ret;
 
@@ -1154,7 +1154,7 @@ static void __driver_attach_async_helper(void *_dev, async_cookie_t cookie)
 
 static int __driver_attach(struct device *dev, void *data)
 {
-	struct device_driver *drv = data;
+	const struct device_driver *drv = data;
 	bool async = false;
 	int ret;
 
@@ -1227,9 +1227,10 @@ static int __driver_attach(struct device *dev, void *data)
  * returns 0 and the @dev->driver is set, we've found a
  * compatible pair.
  */
-int driver_attach(struct device_driver *drv)
+int driver_attach(const struct device_driver *drv)
 {
-	return bus_for_each_dev(drv->bus, NULL, drv, __driver_attach);
+	/* The (void *) will be put back to const * in __driver_attach() */
+	return bus_for_each_dev(drv->bus, NULL, (void *)drv, __driver_attach);
 }
 EXPORT_SYMBOL_GPL(driver_attach);
 

drivers/dma/idxd/compat.c

@@ -7,7 +7,6 @@
 #include <linux/device/bus.h>
 #include "idxd.h"
 
-extern int device_driver_attach(struct device_driver *drv, struct device *dev);
 extern void device_driver_detach(struct device *dev);
 
 #define DRIVER_ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store)	\

include/linux/device.h

@@ -1177,12 +1177,12 @@ static inline void *dev_get_platdata(const struct device *dev)
  * Manual binding of a device to driver. See drivers/base/bus.c
  * for information on use.
  */
-int __must_check device_driver_attach(struct device_driver *drv,
+int __must_check device_driver_attach(const struct device_driver *drv,
 				      struct device *dev);
 int __must_check device_bind_driver(struct device *dev);
 void device_release_driver(struct device *dev);
 int  __must_check device_attach(struct device *dev);
-int __must_check driver_attach(struct device_driver *drv);
+int __must_check driver_attach(const struct device_driver *drv);
 void device_initial_probe(struct device *dev);
 int __must_check device_reprobe(struct device *dev);