driver core: Introduce device_iter_t for device iterating APIs

There are several for_each APIs which has parameter with type below:
int (*fn)(struct device *dev, void *data)
They iterate over various device lists and call @fn() for each device
with caller provided data @*data, and they usually need to modify @*data.

Give the type an dedicated typedef with advantages shown below:
typedef int (*device_iter_t)(struct device *dev, void *data)

- Shorter API declarations and definitions
- Prevent further for_each APIs from using bad parameter type

So introduce device_iter_t and apply it to various existing APIs below:
bus_for_each_dev()
(class|driver)_for_each_device()
device_for_each_child(_reverse|_reverse_from)().

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
Link: https://lore.kernel.org/r/20250105-class_fix-v6-7-3a2f1768d4d4@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

4 files changed, 6 insertions, 6 deletions

diff --git a/drivers/base/bus.c b/drivers/base/bus.c
index 73a56f376d3a..6b9e65a42cd2 100644
--- a/drivers/base/bus.c
+++ b/drivers/base/bus.c
@@ -354,7 +354,7 @@ static struct device *next_device(struct klist_iter *i)
  * count in the supplied callback.
  */
 int bus_for_each_dev(const struct bus_type *bus, struct device *start,
-		     void *data, int (*fn)(struct device *, void *))
+		     void *data, device_iter_t fn)
 {
 	struct subsys_private *sp = bus_to_subsys(bus);
 	struct klist_iter i;
diff --git a/drivers/base/class.c b/drivers/base/class.c
index d57f277978dc..70ee6a7ba5a3 100644
--- a/drivers/base/class.c
+++ b/drivers/base/class.c
@@ -402,7 +402,7 @@ EXPORT_SYMBOL_GPL(class_dev_iter_exit);
  * code.  There's no locking restriction.
  */
 int class_for_each_device(const struct class *class, const struct device *start,
-			  void *data, int (*fn)(struct device *, void *))
+			  void *data, device_iter_t fn)
 {
 	struct subsys_private *sp = class_to_subsys(class);
 	struct class_dev_iter iter;
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 5ee53b3bca6a..7d79a0549ac7 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -3980,7 +3980,7 @@ const char *device_get_devnode(const struct device *dev,
  * other than 0, we break out and return that value.
  */
 int device_for_each_child(struct device *parent, void *data,
-			  int (*fn)(struct device *dev, void *data))
+			  device_iter_t fn)
 {
 	struct klist_iter i;
 	struct device *child;
@@ -4010,7 +4010,7 @@ EXPORT_SYMBOL_GPL(device_for_each_child);
  * other than 0, we break out and return that value.
  */
 int device_for_each_child_reverse(struct device *parent, void *data,
-				  int (*fn)(struct device *dev, void *data))
+				  device_iter_t fn)
 {
 	struct klist_iter i;
 	struct device *child;
@@ -4044,7 +4044,7 @@ EXPORT_SYMBOL_GPL(device_for_each_child_reverse);
  */
 int device_for_each_child_reverse_from(struct device *parent,
 				       struct device *from, void *data,
-				       int (*fn)(struct device *, void *))
+				       device_iter_t fn)
 {
 	struct klist_iter i;
 	struct device *child;
diff --git a/drivers/base/driver.c b/drivers/base/driver.c
index 6f033a741aa7..8ab010ddf709 100644
--- a/drivers/base/driver.c
+++ b/drivers/base/driver.c
@@ -115,7 +115,7 @@ EXPORT_SYMBOL_GPL(driver_set_override);
  * Iterate over the @drv's list of devices calling @fn for each one.
  */
 int driver_for_each_device(struct device_driver *drv, struct device *start,
-			   void *data, int (*fn)(struct device *, void *))
+			   void *data, device_iter_t fn)
 {
 	struct klist_iter i;
 	struct device *dev;