Re: [PATCH v2 2/7] dmaengine: hisilicon: Fix CQ head update

[Jie Hai]

On 2022/7/21 21:27, Vinod Koul wrote:
> On 29-06-22, 11:55, Jie Hai wrote:
> > After completion of data transfer of one or multiple descriptors,
> > the completion status and the current head pointer to submission
> > queue are written into the CQ and interrupt can be generated to
> > inform the software. In interrupt process CQ is read and cq_head
> > is updated.
> >
> > hisi_dma_irq updates cq_head only when the completion status is
> > success. When an abnormal interrupt reports, cq_head will not update
> > which will cause subsequent interrupt processes read the error CQ
> > and never report the correct status.
> >
> > This patch updates cq_head whenever CQ is accessed.
> >
> > Fixes: e9f08b65250d ("dmaengine: hisilicon: Add Kunpeng DMA engine support")
> > Reported-by: kernel test robot <lkp@xxxxxxxxx>
> > Signed-off-by: Jie Hai <haijie1@xxxxxxxxxx>
> > ---
> >   drivers/dma/hisi_dma.c | 10 +++++-----
> >   1 file changed, 5 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/dma/hisi_dma.c b/drivers/dma/hisi_dma.c
> > index 98bc488893cc..7609e6e7eb37 100644
> > --- a/drivers/dma/hisi_dma.c
> > +++ b/drivers/dma/hisi_dma.c
> > @@ -436,12 +436,12 @@ static irqreturn_t hisi_dma_irq(int irq, void *data)
> >   	desc = chan->desc;
> >   	cqe = chan->cq + chan->cq_head;
> >   	if (desc) {
> > +		chan->cq_head = (chan->cq_head + 1) %
> > +				hdma_dev->chan_depth;
>
> This can look better with single line
Thanks for your reviewing.
These issues have been fixed in V3.
> > +		hisi_dma_chan_write(hdma_dev->base,
> > +				    HISI_DMA_CQ_HEAD_PTR, chan->qp_num,
> > +				    chan->cq_head);
>
> maybe two lines?
>
> >   		if (FIELD_GET(STATUS_MASK, cqe->w0) == STATUS_SUCC) {
> > -			chan->cq_head = (chan->cq_head + 1) %
> > -					hdma_dev->chan_depth;
> > -			hisi_dma_chan_write(hdma_dev->base,
> > -					    HISI_DMA_CQ_HEAD_PTR, chan->qp_num,
> > -					    chan->cq_head);
> >   			vchan_cookie_complete(&desc->vd);
> >   		} else {
> >   			dev_err(&hdma_dev->pdev->dev, "task error!\n");
> > --
> > 2.33.0