Re: [PATCH 1/2] cleanup e820_setup_gap

From: Yinghai Lu
Date: Fri Jun 20 2008 - 15:50:45 EST


On Fri, Jun 20, 2008 at 12:38 PM, Alok Kataria <akataria@xxxxxxxxxx> wrote:
> Here is the patch based on tip/master
>
> Please have a look
>
> --
>
> This is a preparatory patch for the next patch in series.
> Moves some code from e820_setup_gap to a new function e820_search_gap.
> This patch is a part of a bug fix where we walk the ACPI table to calculate
> a gap for PCI optional devices.
>
> Signed-off-by: Alok N Kataria <akataria@xxxxxxxxxx>
>
> Index: linux-trees.git/arch/x86/kernel/e820.c
> ===================================================================
> --- linux-trees.git.orig/arch/x86/kernel/e820.c 2008-06-20 10:32:44.000000000 -0700
> +++ linux-trees.git/arch/x86/kernel/e820.c 2008-06-20 12:27:58.000000000 -0700
> @@ -442,26 +442,22 @@
> }
>
> /*
> - * Search for the biggest gap in the low 32 bits of the e820
> - * memory space. We pass this space to PCI to assign MMIO resources
> - * for hotplug or unconfigured devices in.
> - * Hopefully the BIOS let enough space left.
> + * Search for a gap in the e820 memory space from start_addr to 2^32.
> */
> -__init void e820_setup_gap(void)
> +__init int e820_search_gap(unsigned long *gapstart, unsigned long *gapsize,
> + unsigned long start_addr)
> {
> - unsigned long gapstart, gapsize, round;
> - unsigned long long last;
> - int i;
> + unsigned long last = 0x100000000ull;

why changing "unsigned long long" to "unsigned long" ?
it will overflow on 32bit

YH
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