Re: [PATCH 6/7] dmaengine: idxd: handle invalid interrupt handle descriptors

[Dave Jiang <dave.jiang@xxxxxxxxx>]

On 10/24/2021 10:08 PM, Vinod Koul wrote:
> On 20-10-21, 09:54, Dave Jiang wrote:
> > Handle a descriptor that has been marked with invalid interrupt handle
> > error in status. Create a work item that will resubmit the descriptor. This
> > typically happens when the driver has handled the revoke interrupt handle
> > event and has a new interrupt handle.
> >
> > Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
> > Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx>
> > ---
> >   drivers/dma/idxd/dma.c  |   14 +++++++++----
> >   drivers/dma/idxd/idxd.h |    1 +
> >   drivers/dma/idxd/irq.c  |   50 +++++++++++++++++++++++++++++++++++++++++++++++
> >   3 files changed, 61 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/dma/idxd/dma.c b/drivers/dma/idxd/dma.c
> > index 375dbae18583..2ce873994e33 100644
> > --- a/drivers/dma/idxd/dma.c
> > +++ b/drivers/dma/idxd/dma.c
> > @@ -24,18 +24,24 @@ void idxd_dma_complete_txd(struct idxd_desc *desc,
> >   			   enum idxd_complete_type comp_type,
> >   			   bool free_desc)
> >   {
> > +	struct idxd_device *idxd = desc->wq->idxd;
> >   	struct dma_async_tx_descriptor *tx;
> >   	struct dmaengine_result res;
> >   	int complete = 1;
> >   
> > -	if (desc->completion->status == DSA_COMP_SUCCESS)
> > +	if (desc->completion->status == DSA_COMP_SUCCESS) {
> >   		res.result = DMA_TRANS_NOERROR;
> > -	else if (desc->completion->status)
> > +	} else if (desc->completion->status) {
> > +		if (idxd->request_int_handles && comp_type != IDXD_COMPLETE_ABORT &&
> > +		    desc->completion->status == DSA_COMP_INT_HANDLE_INVAL &&
> > +		    idxd_queue_int_handle_resubmit(desc))
> > +			return;
> >   		res.result = DMA_TRANS_WRITE_FAILED;
> > -	else if (comp_type == IDXD_COMPLETE_ABORT)
> > +	} else if (comp_type == IDXD_COMPLETE_ABORT) {
> >   		res.result = DMA_TRANS_ABORTED;
> > -	else
> > +	} else {
> >   		complete = 0;
> > +	}
> >   
> >   	tx = &desc->txd;
> >   	if (complete && tx->cookie) {
> > diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
> > index 970701738c8a..82c4915f58a2 100644
> > --- a/drivers/dma/idxd/idxd.h
> > +++ b/drivers/dma/idxd/idxd.h
> > @@ -524,6 +524,7 @@ void idxd_unregister_devices(struct idxd_device *idxd);
> >   int idxd_register_driver(void);
> >   void idxd_unregister_driver(void);
> >   void idxd_wqs_quiesce(struct idxd_device *idxd);
> > +bool idxd_queue_int_handle_resubmit(struct idxd_desc *desc);
> >   
> >   /* device interrupt control */
> >   void idxd_msix_perm_setup(struct idxd_device *idxd);
> > diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c
> > index 8bca0ed2d23c..26fa871934e6 100644
> > --- a/drivers/dma/idxd/irq.c
> > +++ b/drivers/dma/idxd/irq.c
> > @@ -22,6 +22,11 @@ struct idxd_fault {
> >   	struct idxd_device *idxd;
> >   };
> >   
> > +struct idxd_resubmit {
> > +	struct work_struct work;
> > +	struct idxd_desc *desc;
> > +};
> > +
> >   static void idxd_device_reinit(struct work_struct *work)
> >   {
> >   	struct idxd_device *idxd = container_of(work, struct idxd_device, work);
> > @@ -218,6 +223,51 @@ irqreturn_t idxd_misc_thread(int vec, void *data)
> >   	return IRQ_HANDLED;
> >   }
> >   
> > +static void idxd_int_handle_resubmit_work(struct work_struct *work)
> > +{
> > +	struct idxd_resubmit *irw = container_of(work, struct idxd_resubmit, work);
> > +	struct idxd_desc *desc = irw->desc;
> > +	struct idxd_wq *wq = desc->wq;
> > +	int rc;
> > +
> > +	desc->completion->status = 0;
> > +	rc = idxd_submit_desc(wq, desc);
> > +	if (rc < 0) {
> > +		dev_dbg(&wq->idxd->pdev->dev, "Failed to resubmit desc %d to wq %d.\n",
> > +			desc->id, wq->id);
> > +		/*
> > +		 * If the error is not -EAGAIN, it means the submission failed due to wq
> > +		 * has been killed instead of ENQCMDS failure. Here the driver needs to
> > +		 * notify the submitter of the failure by reporting abort status.
> > +		 *
> > +		 * -EAGAIN comes from ENQCMDS failure. idxd_submit_desc() will handle the
> > +		 * abort.
> > +		 */
> > +		if (rc != -EAGAIN) {
> > +			desc->completion->status = IDXD_COMP_DESC_ABORT;
> > +			idxd_dma_complete_txd(desc, IDXD_COMPLETE_ABORT, false);
> > +		}
> > +		idxd_free_desc(wq, desc);
> > +	}
> > +	kfree(irw);
> > +}
> > +
> > +bool idxd_queue_int_handle_resubmit(struct idxd_desc *desc)
> > +{
> > +	struct idxd_wq *wq = desc->wq;
> > +	struct idxd_device *idxd = wq->idxd;
> > +	struct idxd_resubmit *irw;
> > +
> > +	irw = kzalloc(sizeof(*irw), GFP_KERNEL);
> What is the context of this function, should this be GFP_ATOMIC?

This is done out of a worker thread. So no need for ATOMIC.


> > +	if (!irw)
> > +		return false;
> > +
> > +	irw->desc = desc;
> > +	INIT_WORK(&irw->work, idxd_int_handle_resubmit_work);
> > +	queue_work(idxd->wq, &irw->work);
> > +	return true;
> > +}
> > +
> >   static void irq_process_pending_llist(struct idxd_irq_entry *irq_entry)
> >   {
> >   	struct idxd_desc *desc, *t;