Re: [RFC PATCH v2 00/12] Rewrite asm-generic/bitops/{atomic,lock}.h and use on arm64

From: Masahiro Yamada
Date: Thu Mar 01 2018 - 02:17:58 EST


2018-02-27 0:04 GMT+09:00 Will Deacon <will.deacon@xxxxxxx>:
> Hi everyone,
>
> This is version two of the RFC I previously posted here:
>
> https://www.spinics.net/lists/arm-kernel/msg634719.html
>
> Changes since v1 include:
>
> * Fixed __clear_bit_unlock to work on archs with lock-based atomics
> * Moved lock ops into bitops/lock.h
> * Fixed build breakage on lesser-spotted architectures
>
> Trying to fix the circular #includes introduced by pulling atomic.h
> into btops/lock.h has been driving me insane. I've ended up moving some
> basic BIT definitions into bits.h, but this might all be better in
> const.h which is being proposed by Masahiro. Feedback is especially
> welcome on this part.


Info for reviewers:

You can see my patches at the following:

1/5: https://patchwork.kernel.org/patch/10235457/
2/5: https://patchwork.kernel.org/patch/10235461/
3/5: https://patchwork.kernel.org/patch/10235463/
4/5: https://patchwork.kernel.org/patch/10235469/
5/5: https://patchwork.kernel.org/patch/10235471/


5/5 has conflict with Will's 2/12.

Fortunately, it is at the tail of the series.
It is easy to pick/drop/change
when we decide how to organize it.








> I've not bothered optimising for the case of a 64-bit, big-endian
> architecture that uses the generic implementation of atomic64_t because
> it's both messy and hypothetical. The code here should still work
> correctly for that case, it just sucks (as does the implementation
> currently in mainline).
>
> Cheers,
>
> Will
>
> --->8
>
> Will Deacon (12):
> h8300: Don't include linux/kernel.h in asm/atomic.h
> m68k: Don't use asm-generic/bitops/lock.h
> asm-generic: Move some macros from linux/bitops.h to a new bits.h file
> openrisc: Don't pull in all of linux/bitops.h in asm/cmpxchg.h
> sh: Don't pull in all of linux/bitops.h in asm/cmpxchg-xchg.h
> arm64: fpsimd: include <linux/init.h> in fpsimd.h
> arm64: lse: Include compiler_types.h and export.h for out-of-line
> LL/SC
> arm64: cmpxchg: Include build_bug.h instead of bug.h for BUILD_BUG
> asm-generic/bitops/atomic.h: Rewrite using atomic_fetch_*
> asm-generic/bitops/lock.h: Rewrite using atomic_fetch_*
> arm64: Replace our atomic/lock bitop implementations with asm-generic
> arm64: bitops: Include <asm-generic/bitops/ext2-atomic-setbit.h>
>
> arch/arm64/include/asm/bitops.h | 21 +---
> arch/arm64/include/asm/cmpxchg.h | 2 +-
> arch/arm64/include/asm/fpsimd.h | 1 +
> arch/arm64/include/asm/lse.h | 2 +
> arch/arm64/lib/Makefile | 2 +-
> arch/arm64/lib/bitops.S | 76 ---------------
> arch/h8300/include/asm/atomic.h | 4 +-
> arch/m68k/include/asm/bitops.h | 6 +-
> arch/openrisc/include/asm/cmpxchg.h | 3 +-
> arch/sh/include/asm/cmpxchg-xchg.h | 3 +-
> include/asm-generic/bitops/atomic.h | 188 +++++++-----------------------------
> include/asm-generic/bitops/lock.h | 68 ++++++++++---
> include/asm-generic/bits.h | 26 +++++
> include/linux/bitops.h | 22 +----
> 14 files changed, 135 insertions(+), 289 deletions(-)
> delete mode 100644 arch/arm64/lib/bitops.S
> create mode 100644 include/asm-generic/bits.h
>
> --
> 2.1.4
>



--
Best Regards
Masahiro Yamada