[PATCH v2 00/32] driver core: Constify API device_find_child() and adapt for various existing usages

[Zijun Hu <zijun_hu@xxxxxxxxxx>]

This patch series is to constify the following API:
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.

How to constify the API?

- Now, no (@match)() argument of the API usages is modifying its match
  data @*data after previous cleanup, so it is easy and safe to make its
  parameter @data take const void * as type.

- Simplify involved codes further if it is possbile with benefits
  brought by constifying the API.

Signed-off-by: Zijun Hu <quic_zijuhu@xxxxxxxxxxx>
---
Changes in v2:
- Series v1 have no code review comments and are posted a long time ago, so may ignore differences.
- Link to v1: https://lore.kernel.org/r/20240811-const_dfc_done-v1-0-9d85e3f943cb@xxxxxxxxxxx
- Motivation link: https://lore.kernel.org/lkml/917359cc-a421-41dd-93f4-d28937fe2325@xxxxxxxxxx

---
Zijun Hu (32):
      driver core: Constify API device_find_child()
      driver core: Introduce device_match_type() to match device with a device type
      drm/mediatek: Adapt for constified device_find_child()
      hwmon: Adapt for constified device_find_child()
      media: pci: mgb4: Adapt for constified device_find_child()
      thunderbolt: Adapt for constified device_find_child()
      gpio: sim: Remove gpio_sim_dev_match_fwnode()
      net: dsa: Adapt for constified device_find_child()
      pwm: Adapt for constified device_find_child()
      nvdimm: Adapt for constified device_find_child()
      libnvdimm: Simplify nd_namespace_store() implementation
      firewire: core: Adapt for constified device_find_child()
      serial: core: Adapt for constified device_find_child()
      usb: typec: class: Remove both cable_match() and partner_match()
      usb: typec: class: Adapt for constified device_find_child()
      slimbus: core: Simplify of_find_slim_device() implementation
      slimbus: core: Constify slim_eaddr_equal()
      slimbus: core: Adapt for constified device_find_child()
      scsi: iscsi: Constify API iscsi_find_flashnode_sess()
      scsi: qla4xxx: Adapt for constified iscsi_find_flashnode_sess()
      scsi: iscsi: Adapt for constified device_find_child()
      cxl/region: Adapt for constified device_find_child()
      cxl/pmem: Remove match_nvdimm_bridge()
      cxl/core/pci: Adapt for constified device_find_child()
      cxl/test: Adapt for constified device_find_child()
      sparc: vio: Adapt for constified device_find_child()
      bus: fsl-mc: Adapt for constified device_find_child()
      block: sunvdc: Adapt for constified device_find_child()
      firmware: arm_scmi: Adapt for constified device_find_child()
      efi: dev-path-parser: Adapt for constified device_find_child()
      rpmsg: core: Adapt for constified device_find_child()
      driver core: Simplify API device_find_child_by_name() implementation

 arch/sparc/kernel/vio.c                |  6 +++---
 drivers/base/core.c                    | 30 ++++++++++--------------------
 drivers/block/sunvdc.c                 |  6 +++---
 drivers/bus/fsl-mc/dprc-driver.c       |  6 +++---
 drivers/cxl/core/pci.c                 |  4 ++--
 drivers/cxl/core/pmem.c                |  9 +++------
 drivers/cxl/core/region.c              | 21 ++++++++++++---------
 drivers/firewire/core-device.c         |  4 ++--
 drivers/firmware/arm_scmi/bus.c        |  4 ++--
 drivers/firmware/efi/dev-path-parser.c |  4 ++--
 drivers/gpio/gpio-sim.c                |  7 +------
 drivers/gpu/drm/mediatek/mtk_drm_drv.c |  2 +-
 drivers/hwmon/hwmon.c                  |  2 +-
 drivers/media/pci/mgb4/mgb4_core.c     |  4 ++--
 drivers/nvdimm/bus.c                   |  2 +-
 drivers/nvdimm/claim.c                 |  9 +--------
 drivers/pwm/core.c                     |  2 +-
 drivers/rpmsg/rpmsg_core.c             |  4 ++--
 drivers/scsi/qla4xxx/ql4_os.c          |  3 ++-
 drivers/scsi/scsi_transport_iscsi.c    | 10 +++++-----
 drivers/slimbus/core.c                 | 17 +++++------------
 drivers/thunderbolt/retimer.c          |  2 +-
 drivers/thunderbolt/xdomain.c          |  2 +-
 drivers/tty/serial/serial_core.c       |  4 ++--
 drivers/usb/typec/class.c              | 31 ++++++++++++++-----------------
 include/linux/device.h                 |  4 ++--
 include/linux/device/bus.h             |  1 +
 include/scsi/scsi_transport_iscsi.h    |  4 ++--
 net/dsa/dsa.c                          |  2 +-
 tools/testing/cxl/test/cxl.c           |  2 +-
 30 files changed, 89 insertions(+), 119 deletions(-)
---
base-commit: 40384c840ea1944d7c5a392e8975ed088ecf0b37
change-id: 20241201-const_dfc_done-aaec71e3bbea

Best regards,
-- 
Zijun Hu <quic_zijuhu@xxxxxxxxxxx>