linux-kernel - Re: [PATCH v5 1/8] x86/resctrl: Prepare for new domain scope

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Date:   Wed, 30 Aug 2023 10:53:58 +0200
From:   Maciej Wieczór-Retman 
        <maciej.wieczor-retman@...el.com>
To:     Tony Luck <tony.luck@...el.com>
CC:     Fenghua Yu <fenghua.yu@...el.com>,
        Reinette Chatre <reinette.chatre@...el.com>,
        Peter Newman <peternewman@...gle.com>,
        "Jonathan Corbet" <corbet@....net>,
        Shuah Khan <skhan@...uxfoundation.org>, <x86@...nel.org>,
        Shaopeng Tan <tan.shaopeng@...itsu.com>,
        James Morse <james.morse@....com>,
        Jamie Iles <quic_jiles@...cinc.com>,
        Babu Moger <babu.moger@....com>,
        Randy Dunlap <rdunlap@...radead.org>,
        <linux-kernel@...r.kernel.org>, <linux-doc@...r.kernel.org>,
        <patches@...ts.linux.dev>
Subject: Re: [PATCH v5 1/8] x86/resctrl: Prepare for new domain scope

Hello,

On 2023-08-29 at 16:44:19 -0700, Tony Luck wrote:
>diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
>index 030d3b409768..0d3bae523ecb 100644
>--- a/arch/x86/kernel/cpu/resctrl/core.c
>+++ b/arch/x86/kernel/cpu/resctrl/core.c
>@@ -487,6 +487,21 @@ static int arch_domain_mbm_alloc(u32 num_rmid, struct rdt_hw_domain *hw_dom)
> 	return 0;
> }
> 
>+static int get_domain_id_from_scope(int cpu, enum resctrl_scope scope)
>+{
>+	switch (scope) {
>+	case RESCTRL_L3_CACHE:
>+		return get_cpu_cacheinfo_id(cpu, 3);
>+	case RESCTRL_L2_CACHE:
>+		return get_cpu_cacheinfo_id(cpu, 2);
>+	default:
>+		WARN_ON_ONCE(1);
>+		break;
>+	}
>+
>+	return -1;
>+}

Is there some reason the "return -1" is outside of the default switch
case?

Other switch statements in this patch do have returns inside the default
case, is this one different in some way?

-- 
Kind regards
Maciej Wieczór-Retman