On 2024/12/5 08:10, Zijun Hu wrote:

This patch series is to constify the following API:

This patch series is based on the lasted mainline commit
Commit: feffde684ac2 ("Merge tag 'for-6.13-rc1-tag' of
git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux")
to avoid potential conflict as much as possible.

struct device *device_find_child(struct device *dev, void *data,
		int (*match)(struct device *dev, void *data));
To :
struct device *device_find_child(struct device *dev, const void *data,
				 device_match_t match);
typedef int (*device_match_t)(struct device *dev, const void *data);

Why to constify the API?

- Protect caller's match data @*data which is for comparison and lookup
  and the API does not actually need to modify @*data.

- Make the API's parameters (@match)() and @data have the same type as
  all of other device finding APIs (bus|class|driver)_find_device().

- All kinds of existing device matching functions can be directly taken
  as the API's argument, they were exported by driver core.

What to do?

- Patches [1/11, 3/11] prepare for constifying the API.

- Patch 4/11 constifies the API and adapt for its various subsystem usages.

- Remaining do cleanup for several usages with benefits brought above.