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Date:   Thu, 04 Jun 2020 17:01:43 -0700 (PDT)
Subject:     Re: [PATCH 1/1] riscv: Select ARCH_SUPPORTS_ATOMIC_RMW by default
In-Reply-To: <20200602005428.18087-1-maochenxi@eswin.com>
CC:     Paul Walmsley <paul.walmsley@sifive.com>, aou@eecs.berkeley.edu,
        linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
        maochenxi@eswin.com
From:   Palmer Dabbelt <palmer@dabbelt.com>
To:     maochenxi@eswin.com
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On Mon, 01 Jun 2020 17:54:28 PDT (-0700), maochenxi@eswin.com wrote:
> Enable ARCH_SUPPORTS_ATOMIC_RMW by default to support
> osq_lock in mutex/rwsem locks.
> ---
>  arch/riscv/Kconfig | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index a31e1a41913a..cbdc605d20d9 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -68,6 +68,7 @@ config RISCV
>  	select ARCH_HAS_GCOV_PROFILE_ALL
>  	select HAVE_COPY_THREAD_TLS
>  	select HAVE_ARCH_KASAN if MMU && 64BIT
> +	select ARCH_SUPPORTS_ATOMIC_RMW
>
>  config ARCH_MMAP_RND_BITS_MIN
>  	default 18 if 64BIT

You need a Signed-off-by for all patches, even small ones like this.  I'm also
going to consider this a bit too large of a change to take during the merge
window: there's very little code, but it dramatically changes the behavior of
the system -- in other words, it's a 5.9 candidate, not a 5.8 one.

Thanks!