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Message-ID: <23ed10ee-b88f-8681-35a4-cefc2e3a7800@redhat.com>
Date:   Tue, 19 Sep 2023 11:09:30 +1000
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Subject: Re: [RFC PATCH v2 25/35] LoongArch: Use the __weak version of
 arch_unregister_cpu()
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To:     James Morse <james.morse@arm.com>, linux-pm@vger.kernel.org,
        loongarch@lists.linux.dev, linux-acpi@vger.kernel.org,
        linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-riscv@lists.infradead.org, kvmarm@lists.linux.dev
Cc:     x86@kernel.org, Salil Mehta <salil.mehta@huawei.com>,
        Russell King <linux@armlinux.org.uk>,
        Jean-Philippe Brucker <jean-philippe@linaro.org>,
        jianyong.wu@arm.com, justin.he@arm.com
References: <20230913163823.7880-1-james.morse@arm.com>
 <20230913163823.7880-26-james.morse@arm.com>
From:   Gavin Shan <gshan@redhat.com>
In-Reply-To: <20230913163823.7880-26-james.morse@arm.com>
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On 9/14/23 02:38, James Morse wrote:
> LoongArch provides its own arch_unregister_cpu(). This clears the
> hotpluggable flag, then unregisters the CPU.
> 
> It isn't necessary to clear the hotpluggable flag when unregistering
> a cpu. unregister_cpu() writes NULL to the percpu cpu_sys_devices
> pointer, meaning cpu_is_hotpluggable() will return false, as
> get_cpu_device() has returned NULL.
> 
> Remove arch_unregister_cpu() and use the __weak version.
> 
> Signed-off-by: James Morse <james.morse@arm.com>
> ---
>   arch/loongarch/kernel/topology.c | 9 ---------
>   1 file changed, 9 deletions(-)
> 
I think arch/x86/kernel/topology.c::arch_unregister_cpu() can be dropped either.

Reviewed-by: Gavin Shan <gshan@redhat.com>

> diff --git a/arch/loongarch/kernel/topology.c b/arch/loongarch/kernel/topology.c
> index 8e4441c1ff39..5a75e2cc0848 100644
> --- a/arch/loongarch/kernel/topology.c
> +++ b/arch/loongarch/kernel/topology.c
> @@ -16,13 +16,4 @@ int arch_register_cpu(int cpu)
>   	return register_cpu(c, cpu);
>   }
>   EXPORT_SYMBOL(arch_register_cpu);
> -
> -void arch_unregister_cpu(int cpu)
> -{
> -	struct cpu *c = &per_cpu(cpu_devices, cpu);
> -
> -	c->hotpluggable = 0;
> -	unregister_cpu(c);
> -}
> -EXPORT_SYMBOL(arch_unregister_cpu);
>   #endif

Thanks,
Gavin