Re: [PATCH v6 02/16] cpu: Do not warn on arch_register_cpu() returning -EPROBE_DEFER

From: "Russell King (Oracle)" <linux@armlinux.org.uk>
To: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Peter Zijlstra <peterz@infradead.org>,
	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, kvmarm@lists.linux.dev,
	x86@kernel.org, "Rafael J . Wysocki" <rafael@kernel.org>,
	Miguel Luis <miguel.luis@oracle.com>,
	James Morse <james.morse@arm.com>,
	Salil Mehta <salil.mehta@huawei.com>,
	Jean-Philippe Brucker <jean-philippe@linaro.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>, Ingo Molnar <mingo@redhat.com>,
	Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	linuxarm@huawei.com, justin.he@arm.com, jianyong.wu@arm.com
Subject: Re: [PATCH v6 02/16] cpu: Do not warn on arch_register_cpu() returning -EPROBE_DEFER
Date: Wed, 17 Apr 2024 15:01:33 +0100	[thread overview]
Message-ID: <Zh/WPYMJYepLbST/@shell.armlinux.org.uk> (raw)
In-Reply-To: <20240417131909.7925-3-Jonathan.Cameron@huawei.com>

On Wed, Apr 17, 2024 at 02:18:55PM +0100, Jonathan Cameron wrote:
> For arm64 the CPU registration cannot complete until the ACPI
> interpreter us up and running so in those cases the arch specific
> arch_register_cpu() will return -EPROBE_DEFER at this stage and the
> registration will be attempted later.
> 
> Suggested-by: Rafael J. Wysocki <rafael@kernel.org>
> Acked-by: Rafael J. Wysocki <rafael@kernel.org>
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> 
> ---
> v6: tags
> ---
>  drivers/base/cpu.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
> index 56fba44ba391..b9d0d14e5960 100644
> --- a/drivers/base/cpu.c
> +++ b/drivers/base/cpu.c
> @@ -558,7 +558,7 @@ static void __init cpu_dev_register_generic(void)
>  
>  	for_each_present_cpu(i) {
>  		ret = arch_register_cpu(i);
> -		if (ret)
> +		if (ret != -EPROBE_DEFER)
>  			pr_warn("register_cpu %d failed (%d)\n", i, ret);

This looks very broken to me.

		if (ret && ret != -EPROBE_DEFER)

surely, because we don't want to print a warning if arch_register_cpu()
was successful?

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