[PATCH v5 7/8] driver core: Introduce device_iter_t for device iterating APIs

[Zijun Hu <zijun_hu@icloud.com>]

From: Zijun Hu <quic_zijuhu@quicinc.com>

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>
---
 drivers/base/bus.c            | 2 +-
 drivers/base/class.c          | 2 +-
 drivers/base/core.c           | 6 +++---
 drivers/base/driver.c         | 2 +-
 include/linux/device.h        | 6 +++---
 include/linux/device/bus.h    | 7 +++++--
 include/linux/device/class.h  | 4 ++--
 include/linux/device/driver.h | 2 +-
 8 files changed, 17 insertions(+), 14 deletions(-)

diff --git a/drivers/base/bus.c b/drivers/base/bus.c
index 73a56f376d3a05962ce0931a2fe8b4d8839157f2..6b9e65a42cd2e12046ddabf2d8dfb209d513f7da 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 d57f277978dc9033fba3484b4620bcf884a4029f..70ee6a7ba5a3746b5a182c6101b5c085b424d01d 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 7be9c732bec1b060a477b362f555c3e87c8c7b91..930e43a970952b20cd1c71856bdef889698f51b4 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 6f033a741aa7ce6138d1c61e49e72b2a3eb85e06..8ab010ddf709a2b173cfd0c18610a122e58a2f4c 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;
diff --git a/include/linux/device.h b/include/linux/device.h
index 025bac08fca7b2513acb1fbcb666be1dc64f03d1..36d1a1607712f5a6b0668ac02a6cf6b2d0651a2d 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -1075,12 +1075,12 @@ void device_del(struct device *dev);
 DEFINE_FREE(device_del, struct device *, if (_T) device_del(_T))
 
 int device_for_each_child(struct device *parent, void *data,
-			  int (*fn)(struct device *dev, void *data));
+			  device_iter_t fn);
 int device_for_each_child_reverse(struct device *parent, void *data,
-				  int (*fn)(struct device *dev, void *data));
+				  device_iter_t fn);
 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 device *device_find_child(struct device *parent, const void *data,
 				 device_match_t match);
 struct device *device_find_child_by_name(struct device *parent,
diff --git a/include/linux/device/bus.h b/include/linux/device/bus.h
index bc3fd74bb763e6d2d862859bd2ec3f0d443f2d7a..3d3517da41a141aeadc8f219a44fd360cfd931ff 100644
--- a/include/linux/device/bus.h
+++ b/include/linux/device/bus.h
@@ -139,9 +139,12 @@ int device_match_acpi_dev(struct device *dev, const void *adev);
 int device_match_acpi_handle(struct device *dev, const void *handle);
 int device_match_any(struct device *dev, const void *unused);
 
+/* Device iterating function type for various driver core for_each APIs */
+typedef int (*device_iter_t)(struct device *dev, void *data);
+
 /* iterator helpers for buses */
-int bus_for_each_dev(const struct bus_type *bus, struct device *start, void *data,
-		     int (*fn)(struct device *dev, void *data));
+int bus_for_each_dev(const struct bus_type *bus, struct device *start,
+		     void *data, device_iter_t fn);
 struct device *bus_find_device(const struct bus_type *bus, struct device *start,
 			       const void *data, device_match_t match);
 /**
diff --git a/include/linux/device/class.h b/include/linux/device/class.h
index 518c9c83d64bdf85bb5607cea6ea640884ec3460..aa67d473681612f24a4569bf82fe5f91237d5a50 100644
--- a/include/linux/device/class.h
+++ b/include/linux/device/class.h
@@ -92,8 +92,8 @@ void class_dev_iter_init(struct class_dev_iter *iter, const struct class *class,
 struct device *class_dev_iter_next(struct class_dev_iter *iter);
 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));
+int class_for_each_device(const struct class *class, const struct device *start,
+			  void *data, device_iter_t fn);
 struct device *class_find_device(const struct class *class, const struct device *start,
 				 const void *data, device_match_t match);
 
diff --git a/include/linux/device/driver.h b/include/linux/device/driver.h
index 5c04b8e3833b995f9fd4d65b8732b3dfce2eba7e..cd8e0f0a634be9ea63ff22e89d66ada3b1a9eaf2 100644
--- a/include/linux/device/driver.h
+++ b/include/linux/device/driver.h
@@ -154,7 +154,7 @@ void driver_remove_file(const struct device_driver *driver,
 int driver_set_override(struct device *dev, const char **override,
 			const char *s, size_t len);
 int __must_check driver_for_each_device(struct device_driver *drv, struct device *start,
-					void *data, int (*fn)(struct device *dev, void *));
+					void *data, device_iter_t fn);
 struct device *driver_find_device(const struct device_driver *drv,
 				  struct device *start, const void *data,
 				  device_match_t match);

-- 
2.34.1