linux-kernel - Re: aperture_64.c: corner case wrong

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Date:	Mon, 26 May 2008 17:18:00 -0700
From:	"Yinghai Lu" <yhlu.kernel@...il.com>
To:	"Pavel Machek" <pavel@...e.cz>
Cc:	"kernel list" <linux-kernel@...r.kernel.org>,
	"Ingo Molnar" <mingo@...e.hu>,
	"Dave Jones" <davej@...emonkey.org.uk>,
	"Andi Kleen" <andi@...stfloor.org>
Subject: Re: aperture_64.c: corner case wrong

On Mon, May 26, 2008 at 12:17 PM, Pavel Machek <pavel@...e.cz> wrote:
>
> If
>
> fix == 0, aper_enabled == 1, gart_fix_e820 == 0
>
>        if (!fix && !aper_enabled)
>                return;
>
>        if (gart_fix_e820 && !fix && aper_enabled) {
>                if (e820_any_mapped(aper_base, aper_base + aper_size,
>                                    E820_RAM)) {
>                        /* reserve it, so we can reuse it in second
> kernel */
>                        printk(KERN_INFO "update e820 for GART\n");
>                        add_memory_region(aper_base, aper_size,
> E820_RESERVED);
>                        update_e820();
>                }
>                return;
>        }
>
>        /* different nodes have different setting, disable them all atfirst*/
>
> we'll fall back here and disable all the settings, even when they were
> all consistent.
>
> What about this? (I hope it compiles...)
>
> Signed-off-by: Pavel Machek <pavel@...e.cz>
>
>
> diff --git a/arch/x86/kernel/aperture_64.c b/arch/x86/kernel/aperture_64.c
> index 02f4dba..aa4876a 100644
> --- a/arch/x86/kernel/aperture_64.c
> +++ b/arch/x86/kernel/aperture_64.c
> @@ -344,14 +323,16 @@ out:
>        if (gart_fix_e820 && !fix && aper_enabled) {
>                if (!e820_all_mapped(aper_base, aper_base + aper_size,
>                                    E820_RESERVED)) {
>                        /* reserve it, so we can reuse it in second kernel */
>                        printk(KERN_INFO "update e820 for GART\n");
>                        add_memory_region(aper_base, aper_size, E820_RESERVED);
>                        update_e820();
>                }
> -               return;
>        }
>
> +       if (!fix)
> +               return;
> +
>        /* different nodes have different setting, disable them all at first*/
>        for (i = 0; i < ARRAY_SIZE(bus_dev_ranges); i++) {
>                int bus;
>
good catch.

Acked-by: Yinghai Lu <yhlu.kernel@...il.com>

YH
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