[PATCH v2 00/18] Introduce and use generic parity16/32/64 helper

Kuan-Wei Chiu
2025-03-01T14:25:15Z

Several parts of the kernel contain redundant implementations of parity
calculations for 16/32/64-bit values. Introduces generic
parity16/32/64() helpers in bitops.h, providing a standardized
and optimized implementation.

Subsequent patches refactor various kernel components to replace
open-coded parity calculations with the new helpers, reducing code
duplication and improving maintainability.

Co-developed-by: Yu-Chun Lin <eleanor15x@gmail.com>
Signed-off-by: Yu-Chun Lin <eleanor15x@gmail.com>
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
---

This patch series is based on next-20250228.

Changes in v2:
- Provide fallback functions for __builtin_parity() when the compiler
decides not to inline it
- Use __builtin_parity() when no architecture-specific implementation
is available
- Optimize for constant folding when val is a compile-time constant
- Add a generic parity() macro
- Drop the x86 bootflag conversion patch since it has been merged into
the tip tree

Kuan-Wei Chiu (18):
lib/parity: Add __builtin_parity() fallback implementations
bitops: Optimize parity8() using __builtin_parity()
bitops: Add parity16(), parity32(), and parity64() helpers
media: media/test_drivers: Replace open-coded parity calculation with
parity8()
media: pci: cx18-av-vbi: Replace open-coded parity calculation with
parity8()
media: saa7115: Replace open-coded parity calculation with parity8()
serial: max3100: Replace open-coded parity calculation with parity8()
lib/bch: Replace open-coded parity calculation with parity32()
Input: joystick - Replace open-coded parity calculation with
parity32()
net: ethernet: oa_tc6: Replace open-coded parity calculation with
parity32()
wifi: brcm80211: Replace open-coded parity calculation with parity32()
drm/bridge: dw-hdmi: Replace open-coded parity calculation with
parity32()
mtd: ssfdc: Replace open-coded parity calculation with parity32()
fsi: i2cr: Replace open-coded parity calculation with parity32()
fsi: i2cr: Replace open-coded parity calculation with parity64()
Input: joystick - Replace open-coded parity calculation with
parity64()
nfp: bpf: Replace open-coded parity calculation with parity64()
bitops: Add parity() macro for automatic type-based selection

drivers/fsi/fsi-master-i2cr.c | 18 +--
.../drm/bridge/synopsys/dw-hdmi-ahb-audio.c | 8 +-
drivers/input/joystick/grip_mp.c | 17 +--
drivers/input/joystick/sidewinder.c | 24 +---
drivers/media/i2c/saa7115.c | 12 +-
drivers/media/pci/cx18/cx18-av-vbi.c | 12 +-
.../media/test-drivers/vivid/vivid-vbi-gen.c | 8 +-
drivers/mtd/ssfdc.c | 17 +--
drivers/net/ethernet/netronome/nfp/nfp_asm.c | 7 +-
drivers/net/ethernet/oa_tc6.c | 19 +--
.../broadcom/brcm80211/brcmsmac/dma.c | 16 +--
drivers/tty/serial/max3100.c | 3 +-
include/linux/bitops.h | 115 ++++++++++++++++--
lib/Makefile | 2 +-
lib/bch.c | 14 +--
lib/parity.c | 48 ++++++++
16 files changed, 185 insertions(+), 155 deletions(-)
create mode 100644 lib/parity.c

--
2.34.1