Re: [PATCH 13/16] nvme-pci: Convert to using dma_map_sg_p2pdma for p2pdma pages

On 2021-05-02 7:34 p.m., John Hubbard wrote:

quoted

  	if (iod->npages == 0)
  		dma_pool_free(dev->prp_small_pool, nvme_pci_iod_list(req)[0],
  			      iod->first_dma);

@@ -868,14 +857,13 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
  	if (!iod->nents)
  		goto out_free_sg;
  
-	if (is_pci_p2pdma_page(sg_page(iod->sg)))
-		nr_mapped = pci_p2pdma_map_sg_attrs(dev->dev, iod->sg,
-				iod->nents, rq_dma_dir(req), DMA_ATTR_NO_WARN);
-	else
-		nr_mapped = dma_map_sg_attrs(dev->dev, iod->sg, iod->nents,
-					     rq_dma_dir(req), DMA_ATTR_NO_WARN);
-	if (!nr_mapped)
+	nr_mapped = dma_map_sg_p2pdma_attrs(dev->dev, iod->sg, iod->nents,
+				     rq_dma_dir(req), DMA_ATTR_NO_WARN);
+	if (nr_mapped < 0) {
+		if (nr_mapped != -ENOMEM)
+			ret = BLK_STS_TARGET;
  		goto out_free_sg;
+	}

But now the "nr_mapped == 0" case is no longer doing an early out_free_sg.
Is that OK?

dma_map_sg_p2pdma_attrs() never returns zero. It will return -ENOMEM in
the same situation and results in the same goto out_free_sg.

Logan