Messages in this thread | | | Date | Mon, 18 Jun 2012 15:05:19 -0700 | From | Tejun Heo <> | Subject | Re: [PATCH] memblock: Make sure reserved.regions is freed really |
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Hello, Yinghai.
On Fri, Jun 15, 2012 at 08:12:11PM -0700, Yinghai Lu wrote: > memblock_free() would double reserved.regions too, so we could free > old range for reserved.regions. > > So need to check that regions get doubled. If it is doubled, we need to > free it. > > Cc: Tejun Heo <tj@kernel.org> > Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> > Cc: Andrew Morton <akpm@linux-foundation.org> > Signed-off-by: Yinghai Lu <yinghai@kernel.org> > > --- > mm/memblock.c | 23 +++++++++++++++++++++-- > 1 file changed, 21 insertions(+), 2 deletions(-) > > Index: linux-2.6/mm/memblock.c > =================================================================== > --- linux-2.6.orig/mm/memblock.c > +++ linux-2.6/mm/memblock.c > @@ -148,11 +148,26 @@ phys_addr_t __init_memblock memblock_fin > */ > int __init_memblock memblock_free_reserved_regions(void) > { > + struct memblock_region *r; > + int ret; > + > if (memblock.reserved.regions == memblock_reserved_init_regions) > return 0; > > - return memblock_free(__pa(memblock.reserved.regions), > - sizeof(struct memblock_region) * memblock.reserved.max); > + /* > + * During memblock_free, reserved.regions could be doubled, > + * try to check with old one for checking, and need to free the new one. > + */ > + do { > + r = memblock.reserved.regions; > + ret = memblock_free(__pa(memblock.reserved.regions), > + sizeof(struct memblock_region) * memblock.reserved.max); > + > + if (ret) > + break; > + } while (memblock.reserved.regions != r); > + > + return ret; > }
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?
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); }
Thanks.
-- tejun
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