Re: [PATCH 1/1] memblock cleanup: Remove unnecessary check in memblock_find_in_range_node()

[Tang Chen]

On 08/15/2013 11:27 AM, Tejun Heo wrote:
> Hello, Tang.
>
> On Thu, Aug 15, 2013 at 11:23:19AM +0800, Tang Chen wrote:
> > Furthermore, we don't need to check "if (this_end<  size)" actually. Without
> > this confusing check, we only waste some loops. So this patch removes the
> > check.
> >
> > Signed-off-by: Tang Chen<tangchen@xxxxxxxxxxxxxx>
> > ---
> >   mm/memblock.c |    3 ---
> >   1 files changed, 0 insertions(+), 3 deletions(-)
> >
> > diff --git a/mm/memblock.c b/mm/memblock.c
> > index a847bfe..e0c626e 100644
> > --- a/mm/memblock.c
> > +++ b/mm/memblock.c
> > @@ -114,9 +114,6 @@ phys_addr_t __init_memblock memblock_find_in_range_node(phys_addr_t start,
> >   		this_start = clamp(this_start, start, end);
> >   		this_end = clamp(this_end, start, end);
> >
> > -		if (this_end<  size)
> > -			continue;
> > -
> >   		cand = round_down(this_end - size, align);
> >   		if (cand>= this_start)
> >   			return cand;
>
> Hmmm... maybe I'm missing something but are you sure?  "this_end -
> size" can underflow and "cand>= this_start" will be true incorrectly.

Oh, you are right... Please ignore this. I didn't read it carefully.

Thanks.

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