linux-kernel - Re: [RFC PATCH 1/2] x86/acpi: Improve code readablity of early madt processing

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Message-ID: <20200224132152.GB29318@zn.tnic>
Date:   Mon, 24 Feb 2020 14:21:52 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Cao jin <caoj.fnst@...fujitsu.com>
Cc:     x86@...nel.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org,
        rjw@...ysocki.net, len.brown@...el.com, pavel@....cz,
        tglx@...utronix.de, mingo@...hat.com, hpa@...or.com
Subject: Re: [RFC PATCH 1/2] x86/acpi: Improve code readablity of early madt
 processing

On Thu, Jan 23, 2020 at 09:41:43AM +0800, Cao jin wrote:
> Current processing logic is confusing.
> 
> Return value of early_acpi_parse_madt_lapic_addr_ovr() indicates error(< 0),
> parsed entry number(>= 0).

You mean, the count of table entries parsed successfully?

> So, it makes no sense to initialize acpi_lapic & smp_found_config
> seeing no override entry, instead, initialize them seeing MADT.

Err, that logical conclusion is not really clear to me - pls try
again with more detail. I kinda see what you mean by looking at
acpi_process_madt() but before I commit a change like that, I better
have the warm and fuzzy feeling that it is correct and properly
explained in its commit message.

So why did

  cbf9bd603ab1 ("acpi: get boot_cpu_id as early for k8_scan_nodes")

do it this way? Was it wrong or why?

I'm very wary about touching ACPI parsing code for no good reason
because, well, it is ACPI...

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette