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SubjectRe: [PATCH v2 block/for-next] blk-iocost: fix divide-by-zero in transfer_surpluses()
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On 9/11/20 4:40 PM, Tejun Heo wrote:
> Conceptually, root_iocg->hweight_donating must be less than WEIGHT_ONE but
> all hweight calculations round up and thus it may end up >= WEIGHT_ONE
> triggering divide-by-zero and other issues. Bound the value to avoid
> surprises.
>
> Signed-off-by: Tejun Heo <tj@kernel.org>
> Fixes: e08d02aa5fc9 ("blk-iocost: implement Andy's method for donation weight updates")
>
> Signed-off-by: Tejun Heo <tj@kernel.org>
> ---
> Jens, I was flipping between doing max_t(, 1) over the whole divider and
> doing min_t(, WEIGHT_ONE - 1) for hweight_donating. I thought that I as
> testing after the last change but it obviously wasn't and the previous patch
> doesn't compile due to missing type argument. Can you please apply this
> patch instead? I can send an incremental patch if that'd be better. My
> apologies.

Sure, I replaced it. BTW, you had two signed-off-by's in there.

--
Jens Axboe

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