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References: <20231126013921.103133-1-guoren@kernel.org> <ZWSD6v1d9wwOxOYd@FVFF77S0Q05N>
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From:   Guo Ren <guoren@kernel.org>
Date:   Mon, 27 Nov 2023 21:05:48 +0800
Message-ID: <CAJF2gTQQWA3zuz39qbWZR3=Ej7hHwXVi1T-JM2X6-tbqJVD+ag@mail.gmail.com>
Subject: Re: [PATCH V3] locking/atomic: scripts: Exclude arch_atomic(64)_read(set)
 mappings
To:     Mark Rutland <mark.rutland@arm.com>
Cc:     peterz@infradead.org, keescook@chromium.org, paulmck@kernel.org,
        ubizjak@gmail.com, tglx@linutronix.de,
        linux-kernel@vger.kernel.org, Guo Ren <guoren@linux.alibaba.com>
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On Mon, Nov 27, 2023 at 7:56=E2=80=AFPM Mark Rutland <mark.rutland@arm.com>=
 wrote:
>
> On Sat, Nov 25, 2023 at 08:39:21PM -0500, guoren@kernel.org wrote:
> > From: Guo Ren <guoren@linux.alibaba.com>
> >
> > The definitions of atomic(64)_read(set) are relax version, and using
> > them for acquire and release is incorrect, so exclude these mappings.
>
> This was fixed by commit:
>
>   6d2779ecaeb56f92 ("locking/atomic: scripts: fix fallback ifdeffery")
>
> That commit was in v6.6-rc3, and has been backported to stable kernels.
>
> I think you're using an old kernel as a base.
okay, thx for mentioning it.

>
> Thanks,
> Mark.
>
> >
> > Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
> > Signed-off-by: Guo Ren <guoren@kernel.org>
> > ---
> > Changelog:
> > v3:
> >  - Minimize modification on atomic(64)_read(set)
> >
> > v2:
> >  - Use gen-atomic-fallback.sh instead of header modification
> > ---
> >  include/linux/atomic/atomic-arch-fallback.h | 10 +---------
> >  scripts/atomic/gen-atomic-fallback.sh       |  3 ++-
> >  2 files changed, 3 insertions(+), 10 deletions(-)
> >
> > diff --git a/include/linux/atomic/atomic-arch-fallback.h b/include/linu=
x/atomic/atomic-arch-fallback.h
> > index 18f5744dfb5d..b83ef19da13d 100644
> > --- a/include/linux/atomic/atomic-arch-fallback.h
> > +++ b/include/linux/atomic/atomic-arch-fallback.h
> > @@ -459,8 +459,6 @@ raw_atomic_read_acquire(const atomic_t *v)
> >  {
> >  #if defined(arch_atomic_read_acquire)
> >       return arch_atomic_read_acquire(v);
> > -#elif defined(arch_atomic_read)
> > -     return arch_atomic_read(v);
> >  #else
> >       int ret;
> >
> > @@ -508,8 +506,6 @@ raw_atomic_set_release(atomic_t *v, int i)
> >  {
> >  #if defined(arch_atomic_set_release)
> >       arch_atomic_set_release(v, i);
> > -#elif defined(arch_atomic_set)
> > -     arch_atomic_set(v, i);
> >  #else
> >       if (__native_word(atomic_t)) {
> >               smp_store_release(&(v)->counter, i);
> > @@ -2575,8 +2571,6 @@ raw_atomic64_read_acquire(const atomic64_t *v)
> >  {
> >  #if defined(arch_atomic64_read_acquire)
> >       return arch_atomic64_read_acquire(v);
> > -#elif defined(arch_atomic64_read)
> > -     return arch_atomic64_read(v);
> >  #else
> >       s64 ret;
> >
> > @@ -2624,8 +2618,6 @@ raw_atomic64_set_release(atomic64_t *v, s64 i)
> >  {
> >  #if defined(arch_atomic64_set_release)
> >       arch_atomic64_set_release(v, i);
> > -#elif defined(arch_atomic64_set)
> > -     arch_atomic64_set(v, i);
> >  #else
> >       if (__native_word(atomic64_t)) {
> >               smp_store_release(&(v)->counter, i);
> > @@ -4657,4 +4649,4 @@ raw_atomic64_dec_if_positive(atomic64_t *v)
> >  }
> >
> >  #endif /* _LINUX_ATOMIC_FALLBACK_H */
> > -// 202b45c7db600ce36198eb1f1fc2c2d5268ace2d
> > +// 2fdd6702823fa842f9cea57a002e6e4476ae780c
> > diff --git a/scripts/atomic/gen-atomic-fallback.sh b/scripts/atomic/gen=
-atomic-fallback.sh
> > index c0c8a85d7c81..282a1d3c41d4 100755
> > --- a/scripts/atomic/gen-atomic-fallback.sh
> > +++ b/scripts/atomic/gen-atomic-fallback.sh
> > @@ -102,7 +102,8 @@ gen_proto_order_variant()
> >       fi
> >
> >       # Allow ACQUIRE/RELEASE/RELAXED ops to be defined in terms of FUL=
L ops
> > -     if [ ! -z "${order}" ]; then
> > +     # Exclude arch_atomic(64)_read(set) mappings because these are no=
t FULL ops.
> > +     if [ ! -z "${order}" ] && [ "${name}" !=3D "read" ] && [ "${name}=
" !=3D "set" ]; then
> >               printf "#elif defined(arch_${basename})\n"
> >               printf "\t${retstmt}arch_${basename}(${args});\n"
> >       fi
> > --
> > 2.36.1
> >


--=20
Best Regards
 Guo Ren