Re: [PATCH for-next 1/2] IB/rdmavt: Setting of QP timeout can overflow jiffies computation

[Doug Ledford <dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

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On 6/17/2017 1:37 PM, Dennis Dalessandro wrote:
> From: Kaike Wan <kaike.wan-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> 
> Current computation of qp->timeout_jiffies in rvt_modify_qp() will cause
> overflow due to the fact that the input to the function usecs_to_jiffies
> is only 32-bit ( unsigned int). Overflow will occur when attr->timeout is
> equal to or greater than 30. The consequence is unnecessarily excessive
> retry and thus degradation of the system performance.
> 
> This patch fixes the problem by limiting the input to 5-bit and calling
> usecs_to_jiffies() before multiplying the scaling factor.
> 
> Reviewed-by: Mike Marciniszyn <mike.marciniszyn-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> Signed-off-by: Kaike Wan <kaike.wan-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> Signed-off-by: Dennis Dalessandro <dennis.dalessandro-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>

This was accepted into 4.13-rc, thanks.

-- 
Doug Ledford <dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
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