static blk_status_t nvme_map_data()

in host/pci.c [837:891]

• 48 lines of code
• 13 McCabe index (conditional complexity)

static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
		struct nvme_command *cmnd)
{
	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
	blk_status_t ret = BLK_STS_RESOURCE;
	int nr_mapped;

	if (blk_rq_nr_phys_segments(req) == 1) {
		struct bio_vec bv = req_bvec(req);

		if (!is_pci_p2pdma_page(bv.bv_page)) {
			if (bv.bv_offset + bv.bv_len <= NVME_CTRL_PAGE_SIZE * 2)
				return nvme_setup_prp_simple(dev, req,
							     &cmnd->rw, &bv);

			if (iod->nvmeq->qid && sgl_threshold &&
			    nvme_ctrl_sgl_supported(&dev->ctrl))
				return nvme_setup_sgl_simple(dev, req,
							     &cmnd->rw, &bv);
		}
	}

	iod->dma_len = 0;
	iod->sg = mempool_alloc(dev->iod_mempool, GFP_ATOMIC);
	if (!iod->sg)
		return BLK_STS_RESOURCE;
	sg_init_table(iod->sg, blk_rq_nr_phys_segments(req));
	iod->nents = blk_rq_map_sg(req->q, req, iod->sg);
	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)
		goto out_free_sg;

	iod->use_sgl = nvme_pci_use_sgls(dev, req);
	if (iod->use_sgl)
		ret = nvme_pci_setup_sgls(dev, req, &cmnd->rw, nr_mapped);
	else
		ret = nvme_pci_setup_prps(dev, req, &cmnd->rw);
	if (ret != BLK_STS_OK)
		goto out_unmap_sg;
	return BLK_STS_OK;

out_unmap_sg:
	nvme_unmap_sg(dev, req);
out_free_sg:
	mempool_free(iod->sg, dev->iod_mempool);
	return ret;
}