linux-kernel - Re: [PATCH v2] x86/resctrl: Fix unused variable warning in cache_alloc_hsw

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Message-ID: <3ca2b0ed-6732-4fc4-a5fe-1846b873b02c@intel.com>
Date:   Thu, 2 Nov 2023 14:34:19 -0700
From:   Reinette Chatre <reinette.chatre@...el.com>
To:     Tony Luck <tony.luck@...el.com>, "Moger, Babu" <babu.moger@....com>
CC:     "Yu, Fenghua" <fenghua.yu@...el.com>,
        Peter Newman <peternewman@...gle.com>,
        "x86@...nel.org" <x86@...nel.org>,
        Shaopeng Tan <tan.shaopeng@...itsu.com>,
        James Morse <james.morse@....com>,
        Jamie Iles <quic_jiles@...cinc.com>,
        Randy Dunlap <rdunlap@...radead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "patches@...ts.linux.dev" <patches@...ts.linux.dev>
Subject: Re: [PATCH v2] x86/resctrl: Fix unused variable warning in
 cache_alloc_hsw_probe()

Hi Tony,

On 11/1/2023 2:26 PM, Tony Luck wrote:
> In a "W=1" build gcc throws a warning:

This is strange, I am not able to encounter this warning. Is my gcc perhaps
too old? I know there were some specific versions needed to reproduce similar
warnings with clang (see reference commit 793207bad71c ("x86/resctrl: Fix a silly
-Wunused-but-set-variable warning")).

> 
> arch/x86/kernel/cpu/resctrl/core.c: In function ‘cache_alloc_hsw_probe’:
> arch/x86/kernel/cpu/resctrl/core.c:139:16: warning: variable ‘h’ set but not used
> 
> Fix by switching from wrmsr_safe() to wrmsrl_safe(), and from rdmsr()
> to rdmsrl() using a single u64 argument for the MSR value instead of
> the pair of u32 for the high and low halves.
> 
> Signed-off-by: Tony Luck <tony.luck@...el.com>

I do not know if all the text from that reference commit applies here, but
for what it is worth:

Acked-by: Reinette Chatre <reinette.chatre@...el.com>

Reinette