Re: [PATCH 1/2] cleanup e820_setup_gap

From: Ingo Molnar
Date: Tue Jun 24 2008 - 08:08:38 EST



* Alok Kataria <akataria@xxxxxxxxxx> wrote:

> On Fri, 2008-06-20 at 12:50 -0700, Yinghai Lu wrote:
> > 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
> >
>
> Oops...my bad, it was unsigned long in e820_64.c. Should be more careful
> with these cross ports.
> Thanks for catching it.

ok, could you please resend the fixed up series? This breakage would be
a nasty bisection point which we want to avoid.

Ingo
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