linux-kernel - Re: [RFC PATCH v3 0/6] Deduplicating RISCV cmpxchg.h macros

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Date:   Thu, 6 Apr 2023 10:39:58 +0800
From:   Guo Ren <guoren@...nel.org>
To:     Leonardo Bras <leobras@...hat.com>
Cc:     Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Andrea Parri <parri.andrea@...il.com>,
        Conor Dooley <conor.dooley@...rochip.com>,
        linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH v3 0/6] Deduplicating RISCV cmpxchg.h macros

Thx Leonardo,

It's a good point for cleaning up.

On Wed, Apr 5, 2023 at 12:37 AM Leonardo Bras <leobras@...hat.com> wrote:
>
> While studying riscv's cmpxchg.h file, I got really interested in
> understanding how RISCV asm implemented the different versions of
> {cmp,}xchg.
>
> When I understood the pattern, it made sense for me to remove the
> duplications and create macros to make it easier to understand what exactly
> changes between the versions: Instruction sufixes & barriers.
>
> I split those changes in 3 levels for each cmpxchg and xchg, resulting a
But how about merging 3 levels into one? (I mean one for cmpxchg and
one for xchg, resulting in 2 patches.)

> total of 6 patches. I did this so it becomes easier to review and remove
> the last levels if desired, but I have no issue squashing them if it's
> better.
>
> Please provide comments.
>
> Thanks!
> Leo
>
> Changes since v2:
> - Fixed  macros that depend on having a local variable with a magic name
> - Previous cast to (long) is now only applied on 4-bytes cmpxchg
>
> Changes since v1:
> - Fixed patch 4/6 suffix from 'w.aqrl' to '.w.aqrl', to avoid build error
>
>
> Leonardo Bras (6):
>   riscv/cmpxchg: Deduplicate cmpxchg() asm functions
>   riscv/cmpxchg: Deduplicate cmpxchg() macros
>   riscv/cmpxchg: Deduplicate arch_cmpxchg() macros
>   riscv/cmpxchg: Deduplicate xchg() asm functions
>   riscv/cmpxchg: Deduplicate xchg() macros
>   riscv/cmpxchg: Deduplicate arch_xchg() macros
>
>  arch/riscv/include/asm/cmpxchg.h | 319 +++++++------------------------
>  1 file changed, 67 insertions(+), 252 deletions(-)
>
> --
> 2.40.0
>


-- 
Best Regards
 Guo Ren