From: Vineet Gupta <vgupta@kernel.org>
To: paulmck@kernel.org, linux-arch@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-snps-arc@lists.infradead.org
Cc: vgupta@kernel.org
Subject: Re: ARC: Use __force to suppress per-CPU cmpxchg complaints
Date: Tue, 15 Oct 2024 22:33:14 -0700 [thread overview]
Message-ID: <c1afa8ac-5c6a-4966-975d-915887c8106d@kernel.org> (raw)
In-Reply-To: <c88fafb4-47d9-49b6-aeb6-5a83c9778791@paulmck-laptop>
On 10/9/24 10:55, Paul E. McKenney wrote:
> Currently, the cast of the first argument to cmpxchg_emu_u8() drops the
> __percpu address-space designator, which results in sparse complaints
> when applying cmpxchg() to per-CPU variables in ARC. Therefore, use
> __force to suppress these complaints, given that this does not pertain
> to cmpxchg() semantics, which are plently well-defined on variables in
> general, whether per-CPU or otherwise.
>
> Reported-by: kernel test robot <lkp@intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202409251336.ToC0TvWB-lkp@intel.com/
> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
> Cc: Vineet Gupta <vgupta@kernel.org>
> Cc: <linux-snps-arc@lists.infradead.org>
>
> diff --git a/arch/arc/include/asm/cmpxchg.h b/arch/arc/include/asm/cmpxchg.h
> index 58045c8983404..76f43db0890fc 100644
> --- a/arch/arc/include/asm/cmpxchg.h
> +++ b/arch/arc/include/asm/cmpxchg.h
> @@ -48,7 +48,7 @@
> \
> switch(sizeof((_p_))) { \
> case 1: \
> - _prev_ = (__typeof__(*(ptr)))cmpxchg_emu_u8((volatile u8 *)_p_, (uintptr_t)_o_, (uintptr_t)_n_); \
> + _prev_ = (__typeof__(*(ptr)))cmpxchg_emu_u8((volatile u8 *__force)_p_, (uintptr_t)_o_, (uintptr_t)_n_); \
> break; \
> case 4: \
> _prev_ = __cmpxchg(_p_, _o_, _n_); \
Added to for-curr.
Thx,
-Vineet
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next prev parent reply other threads:[~2024-10-16 5:33 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-09 17:55 ARC: Use __force to suppress per-CPU cmpxchg complaints Paul E. McKenney
2024-10-16 5:33 ` Vineet Gupta [this message]
2024-10-16 13:28 ` Paul E. McKenney
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