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 02:15:57PM +0300, Leon Romanovsky wrote:
> 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)) {
> 
> The pvrdma_idx_ring_has_data function can return PVRDMA_INVALID_IDX (-1).

I believe that the case of PVRDMA_INVALID_IDX is only due to some bug. I do
not think it is an expected behaviour, it means that ring is corrupted, am
i right Adit?

> 
> > +			spin_unlock_irqrestore(&cq->cq_lock, flags);
> > +			return 1;
> > +		}
> > +	}
> > +
> > +	spin_unlock_irqrestore(&cq->cq_lock, flags);
> > +
> >  	return 0;
> >  }
> >
> > --
> > 2.7.4
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-rdma" in
> > the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html


--
To unsubscribe from this list: send the line "unsubscribe linux-rdma" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html