Re: [PATCH for-rc] RDMA/vmw_pvrdma: Report CQ missed events

[Yuval Shaia <yuval.shaia-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>]

On Thu, Aug 10, 2017 at 12:46:15AM -0700, Adit Ranadive wrote:
> From: Bryan Tan <bryantan-pghWNbHTmq7QT0dZR+AlfA@public.gmane.org>
> 
> There is a chance of a race between arming the CQ and receiving
> completions. By reporting CQ missed events any ULPs should poll
> again to get the completions.
> 
> Fixes: 29c8d9eba550 ("IB: Add vmw_pvrdma driver")
> Acked-by: Aditya Sarwade <asarwade-pghWNbHTmq7QT0dZR+AlfA@public.gmane.org>
> Signed-off-by: Bryan Tan <bryantan-pghWNbHTmq7QT0dZR+AlfA@public.gmane.org>
> Signed-off-by: Adit Ranadive <aditr-pghWNbHTmq7QT0dZR+AlfA@public.gmane.org>
> ---
>  drivers/infiniband/hw/vmw_pvrdma/pvrdma_cq.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
> 
> diff --git a/drivers/infiniband/hw/vmw_pvrdma/pvrdma_cq.c b/drivers/infiniband/hw/vmw_pvrdma/pvrdma_cq.c
> index 69bda61..f4ab5fa 100644
> --- a/drivers/infiniband/hw/vmw_pvrdma/pvrdma_cq.c
> +++ b/drivers/infiniband/hw/vmw_pvrdma/pvrdma_cq.c
> @@ -65,12 +65,27 @@ int pvrdma_req_notify_cq(struct ib_cq *ibcq,
>  	struct pvrdma_dev *dev = to_vdev(ibcq->device);
>  	struct pvrdma_cq *cq = to_vcq(ibcq);
>  	u32 val = cq->cq_handle;
> +	unsigned long flags;
>  
>  	val |= (notify_flags & IB_CQ_SOLICITED_MASK) == IB_CQ_SOLICITED ?
>  		PVRDMA_UAR_CQ_ARM_SOL : PVRDMA_UAR_CQ_ARM;
>  
> +	spin_lock_irqsave(&cq->cq_lock, flags);
> +
>  	pvrdma_write_uar_cq(dev, val);
>  
> +	if (notify_flags & IB_CQ_REPORT_MISSED_EVENTS) {
> +		unsigned int head;
> +
> +		if (pvrdma_idx_ring_has_data(&cq->ring_state->rx,
> +					     cq->ibcq.cqe, &head)) {
> +			spin_unlock_irqrestore(&cq->cq_lock, flags);
> +			return 1;
> +		}
> +	}
> +
> +	spin_unlock_irqrestore(&cq->cq_lock, flags);
> +

Reviewed-by: Yuval Shaia <yuval.shaia-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>

>  	return 0;
>  }
>  
> -- 
> 2.7.4
> 
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