drivers/base: Introduce device_match_t for device finding APIs

There are several drivers/base APIs for finding a specific device, and
they currently use the following good type for the @match parameter:
int (*match)(struct device *dev, const void *data)

Since these operations do not modify the caller-provided @*data, this
type is worthy of a dedicated typedef:
typedef int (*device_match_t)(struct device *dev, const void *data)

Advantages of using device_match_t:
 - Shorter API declarations and definitions
 - Prevent further APIs from using a bad type for @match

So introduce device_match_t and apply it to the existing
(bus|class|driver|auxiliary)_find_device() APIs.

Signed-off-by: Zijun Hu <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: zijun-hu

drivers/base/auxiliary.c

@@ -352,7 +352,7 @@ EXPORT_SYMBOL_GPL(__auxiliary_device_add);
  */
 struct auxiliary_device *auxiliary_find_device(struct device *start,
 					       const void *data,
-					       int (*match)(struct device *dev, const void *data))
+					       device_match_t match)
 {
 	struct device *dev;
 

drivers/base/bus.c

@@ -391,7 +391,7 @@ EXPORT_SYMBOL_GPL(bus_for_each_dev);
  */
 struct device *bus_find_device(const struct bus_type *bus,
 			       struct device *start, const void *data,
-			       int (*match)(struct device *dev, const void *data))
+			       device_match_t match)
 {
 	struct subsys_private *sp = bus_to_subsys(bus);
 	struct klist_iter i;

drivers/base/class.c

@@ -433,8 +433,7 @@ EXPORT_SYMBOL_GPL(class_for_each_device);
  * code.  There's no locking restriction.
  */
 struct device *class_find_device(const struct class *class, const struct device *start,
-				 const void *data,
-				 int (*match)(struct device *, const void *))
+				 const void *data, device_match_t match)
 {
 	struct subsys_private *sp = class_to_subsys(class);
 	struct class_dev_iter iter;

drivers/base/driver.c

@@ -150,7 +150,7 @@ EXPORT_SYMBOL_GPL(driver_for_each_device);
  */
 struct device *driver_find_device(const struct device_driver *drv,
 				  struct device *start, const void *data,
-				  int (*match)(struct device *dev, const void *data))
+				  device_match_t match)
 {
 	struct klist_iter i;
 	struct device *dev;

include/linux/auxiliary_bus.h

@@ -271,6 +271,6 @@ void auxiliary_driver_unregister(struct auxiliary_driver *auxdrv);
 
 struct auxiliary_device *auxiliary_find_device(struct device *start,
 					       const void *data,
-					       int (*match)(struct device *dev, const void *data));
+					       device_match_t match);
 
 #endif /* _AUXILIARY_BUS_H_ */

include/linux/device/bus.h

@@ -126,6 +126,9 @@ struct bus_attribute {
 int __must_check bus_create_file(const struct bus_type *bus, struct bus_attribute *attr);
 void bus_remove_file(const struct bus_type *bus, struct bus_attribute *attr);
 
+/* Matching function type for drivers/base APIs to find a specific device */
+typedef int (*device_match_t)(struct device *dev, const void *data);
+
 /* Generic device matching functions that all busses can use to match with */
 int device_match_name(struct device *dev, const void *name);
 int device_match_of_node(struct device *dev, const void *np);
@@ -139,8 +142,7 @@ int device_match_any(struct device *dev, const void *unused);
 int bus_for_each_dev(const struct bus_type *bus, struct device *start, void *data,
 		     int (*fn)(struct device *dev, void *data));
 struct device *bus_find_device(const struct bus_type *bus, struct device *start,
-			       const void *data,
-			       int (*match)(struct device *dev, const void *data));
+			       const void *data, device_match_t match);
 /**
  * bus_find_device_by_name - device iterator for locating a particular device
  * of a specific name.

include/linux/device/class.h

@@ -95,7 +95,7 @@ void class_dev_iter_exit(struct class_dev_iter *iter);
 int class_for_each_device(const struct class *class, const struct device *start, void *data,
 			  int (*fn)(struct device *dev, void *data));
 struct device *class_find_device(const struct class *class, const struct device *start,
-				 const void *data, int (*match)(struct device *, const void *));
+				 const void *data, device_match_t match);
 
 /**
  * class_find_device_by_name - device iterator for locating a particular device

include/linux/device/driver.h

@@ -157,7 +157,7 @@ int __must_check driver_for_each_device(struct device_driver *drv, struct device
 					void *data, int (*fn)(struct device *dev, void *));
 struct device *driver_find_device(const struct device_driver *drv,
 				  struct device *start, const void *data,
-				  int (*match)(struct device *dev, const void *data));
+				  device_match_t match);
 
 /**
  * driver_find_device_by_name - device iterator for locating a particular device