linux-kernel - Re: [PATCH] x86/platform/uv: Use sysfs_match_string() for string parsing in param_set

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Message-ID: <4f41e78e-5e47-0726-c64a-82559d1f799b@redhat.com>
Date:   Wed, 13 Sep 2023 19:01:31 +0200
From:   Hans de Goede <hdegoede@...hat.com>
To:     Steve Wahl <steve.wahl@....com>
Cc:     Justin Ernst <justin.ernst@....com>,
        Kyle Meyer <kyle.meyer@....com>,
        Dimitri Sivanich <dimitri.sivanich@....com>,
        Russ Anderson <russ.anderson@....com>,
        Darren Hart <dvhart@...radead.org>,
        Andy Shevchenko <andy@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        "H . Peter Anvin" <hpa@...or.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org, Justin Stitt <justinstitt@...gle.com>
Subject: Re: [PATCH] x86/platform/uv: Use sysfs_match_string() for string
 parsing in param_set_action()

Hi Steve,

On 9/13/23 18:56, Steve Wahl wrote:
> On Wed, Sep 13, 2023 at 05:16:56PM +0200, Hans de Goede wrote:
>> Remove the custom, hard to read code to:
>>
>> 1. Make a copy of "val" with any potential '\n' at the end stripped
>> 2. Compare the copy against an array of allowed string values
>>
>> Linux has the sysfs_match_string() helper exactly for cases like this,
>> switch to this.
> 
> Hans,
> 
> I like this patch, compiling and testing now.
> 
> I was wondering, as long as we're in the neighborhood, how you feel
> about changing the stored variable uv_nmi_action to an int or enum
> rather than a string, since it can only be one of 6 values, and the
> string compare while processing an NMI strikes me as inefficent.
> 
> It could extend this patch, or be done as a follow on.  And I'm
> willing to supply the effort if you want me to.

I must admit I did not look at the code consuming uv_nmi_action
and I did wonder why this was not an enum from day 1.

I'll prepare a v2 of this patch which changes uv_nmi_action
to an enum.

Note I can compile test this only, so I gope you will be able to
test the v2 a bit more thoroughly :)

Regards,

Hans