Re: [PATCH 15/35] x86, lmb: Add lmb_reserve_area_overlap_ok()

From: Benjamin Herrenschmidt
Date: Fri May 14 2010 - 04:49:59 EST


On Thu, 2010-05-13 at 23:44 -0700, Yinghai wrote:
> On 05/13/2010 07:32 PM, Benjamin Herrenschmidt wrote:
> > On Thu, 2010-05-13 at 17:19 -0700, Yinghai Lu wrote:
> >> Some areas from firmware could be reserved several times from different callers.
> >>
> >> If these area are overlapped, We may have overlapped entries in lmb.reserved.
> >>
> >> Try to free the area at first, before rerserve them again.
> >
> > I have already told you to make this a property of lmb_reserve() instead
> > of adding that function with a terrible name.
>
> make every lmb_reserve() call lmb_free at first?

Either that, or make it check for collisions first, and if there's
one, call free and try again. A little bit more work but I plan toq
make it smarter at some stage, ie, directly adjust surrounding ranges
instead which is not -that- hard to do.

Ben.

> >
> > Cheers,
> > Ben.
> >
> >> Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
> >> ---
> >> arch/x86/include/asm/lmb.h | 1 +
> >> arch/x86/mm/lmb.c | 18 ++++++++++++++++++
> >> 2 files changed, 19 insertions(+), 0 deletions(-)
> >>
> >> diff --git a/arch/x86/include/asm/lmb.h b/arch/x86/include/asm/lmb.h
> >> index dd42ac1..9329e09 100644
> >> --- a/arch/x86/include/asm/lmb.h
> >> +++ b/arch/x86/include/asm/lmb.h
> >> @@ -7,6 +7,7 @@ u64 lmb_find_area_size(u64 start, u64 *sizep, u64 align);
> >> void lmb_to_bootmem(u64 start, u64 end);
> >>
> >> void lmb_reserve_area(u64 start, u64 end, char *name);
> >> +void lmb_reserve_area_overlap_ok(u64 start, u64 end, char *name);
> >> void lmb_free_area(u64 start, u64 end);
> >> void lmb_add_memory(u64 start, u64 end);
> >> struct range;
> >> diff --git a/arch/x86/mm/lmb.c b/arch/x86/mm/lmb.c
> >> index 19a5f49..1100c18 100644
> >> --- a/arch/x86/mm/lmb.c
> >> +++ b/arch/x86/mm/lmb.c
> >> @@ -309,6 +309,24 @@ void __init lmb_reserve_area(u64 start, u64 end, char *name)
> >> lmb_add_region(&lmb.reserved, start, end - start);
> >> }
> >>
> >> +/*
> >> + * Could be used to avoid having overlap entries in lmb.reserved.region.
> >> + * Don't need to use it with area that is from lmb_find_area()
> >> + * Only use it for the area that fw hidden area.
> >> + */
> >> +void __init lmb_reserve_area_overlap_ok(u64 start, u64 end, char *name)
> >> +{
> >> + if (start == end)
> >> + return;
> >> +
> >> + if (WARN_ONCE(start > end, "lmb_reserve_area_overlap_ok: wrong range [%#llx, %#llx]\n", start, end))
> >> + return;
> >> +
> >> + /* Free that region at first */
> >> + lmb_free(start, end - start);
> >> + lmb_add_region(&lmb.reserved, start, end - start);
> >> +}
> >> +
> >> void __init lmb_free_area(u64 start, u64 end)
> >> {
> >> if (start == end)
> >
>
> --
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