Re: [PATCH 1/2] cleanup e820_setup_gap

["Yinghai Lu" <yhlu.kernel@gmail.com>]

On Fri, Jun 20, 2008 at 12:38 PM, Alok Kataria <akataria@vmware.com> 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@vmware.com>
>
> 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