linux-kernel - Re: [PATCH v2 1/2] mce: acpi/apei: Honour Firmware First for MCA banks listed in APEI HEST CMC

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Date:	Thu, 20 Jun 2013 22:57:26 +0200
From:	Borislav Petkov <bp@...en8.de>
To:	"Naveen N. Rao" <naveen.n.rao@...ux.vnet.ibm.com>
Cc:	tony.luck@...el.com, ananth@...ibm.com, masbock@...ux.vnet.ibm.com,
	lcm@...ux.vnet.ibm.com, linux-kernel@...r.kernel.org,
	linux-acpi@...r.kernel.org, ying.huang@...el.com
Subject: Re: [PATCH v2 1/2] mce: acpi/apei: Honour Firmware First for MCA
 banks listed in APEI HEST CMC

On Fri, Jun 21, 2013 at 01:44:00AM +0530, Naveen N. Rao wrote:
> This won't work across cpu offline/online, right? We will end up
> _not_ enabling CMCI on certain banks where we should have.

Huh, don't understand. cmci_discover runs on each CPU. After you've run
hest_parse_cmc early during boot and cleared the mce_poll_banks bits,
nothing will set them again so CPU hotplug doesn't matter...

> Another thing: for hest_parse_cmc(), does the below look good?
> 
>         cmc = (struct acpi_hest_ia_corrected *)hest_hdr;
>         if (!cmc->enabled)
>                 return 0;
> 
> #define ACPI_HEST_PARSING_DONE 1
>         /*
>          * We expect HEST to provide a list of MC banks that
>          * report errors in firmware first mode.
>          */
>         if (!(cmc->flags & ACPI_HEST_FIRMWARE_FIRST) ||
> !cmc->num_hardware_banks)
>                 return ACPI_HEST_PARSING_DONE;
> 
> The return value doesn't really matter since we don't check it, but
> returning an error looked like the wrong thing to do as well.

I'd add a comment above the "return 1" statement to explain why I'm
doing this. It is much more verbose even than a well-named macro :)

Thanks.

-- 
Regards/Gruss,
    Boris.

Sent from a fat crate under my desk. Formatting is fine.
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