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SubjectRe: [PATCH] memblock: Make sure reserved.regions is freed really
Hey, Yinghai.

On Mon, Jun 18, 2012 at 03:58:52PM -0700, Yinghai Lu wrote:
> > Hmmm... nice catch but I think it's a bit complex and ugly.  In this
> > case, we *know* that the region isn't gonna be split.  Maybe a better
> > option is to add something like the following?
>
> how do you know __pa(memblock.reserved.regions) would not be merged
> with other entries
> in reserved.regions?
>
> >
> > void memblock_remove_region_by_ptr(struct memblock_type *type,
> >                                   struct memblock_region *r)
> > {
> >        WARN_ON(/* make sure @r is inside @type->regions */);
> >        memblock_remove_region(type, r - type->regions);
> > }
>
> you want to change

Heh, you're right. My suggestion was completely bonkers. Sorry about
that. Hmm.... how about separating out removal pre-expansion and
doing it before calling into free? ie. something like

static int memblock_prepare_for_isolation(struct memblock_type *type)
{
/* we'll create at most two more regions */
while (type->cnt + 2 > type->max)
if (memblock_double_array(type) < 0)
return -ENOMEM;
return 0;
}

int __init_memblock memblock_free_reserved_regions(void)
{
int ret;

if (memblock.reserved.regions == memblock_reserved_init_regions)
return 0;

ret = memblock_prepare_for_isolation(&memblock.reserved);
if (ret)
return ret;

ret = memblock_free(__pa(memblock.reserved.regions),
sizeof(struct memblock_region) * memblock.reserved.max);
WARN_ON(ret || memblock.reserved.regions has changed);
return ret;
}

Thanks.

--
tejun
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