On Thu, Aug 30, 2018 at 12:53:49PM -0600, Logan Gunthorpe wrote: > For P2P requests, we must use the pci_p2pmem_map_sg() function > instead of the dma_map_sg functions. > > With that, we can then indicate PCI_P2P support in the request queue. > For this, we create an NVME_F_PCI_P2P flag which tells the core to > set QUEUE_FLAG_PCI_P2P in the request queue. > > Signed-off-by: Logan Gunthorpe <[email protected]> > Reviewed-by: Sagi Grimberg <[email protected]> > Reviewed-by: Christoph Hellwig <[email protected]> > drivers/nvme/host/core.c | 4 ++++ > drivers/nvme/host/nvme.h | 1 + > drivers/nvme/host/pci.c | 17 +++++++++++++---- > 3 files changed, 18 insertions(+), 4 deletions(-) > > diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c > index dd8ec1dd9219..6033ce2fd3e9 100644 > +++ b/drivers/nvme/host/core.c > @@ -3051,7 +3051,11 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, > unsigned nsid) > ns->queue = blk_mq_init_queue(ctrl->tagset); > if (IS_ERR(ns->queue)) > goto out_free_ns; > + > blk_queue_flag_set(QUEUE_FLAG_NONROT, ns->queue); > + if (ctrl->ops->flags & NVME_F_PCI_P2PDMA) > + blk_queue_flag_set(QUEUE_FLAG_PCI_P2PDMA, ns->queue); > + > ns->queue->queuedata = ns; > ns->ctrl = ctrl; > > diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h > index bb4a2003c097..4030743c90aa 100644 > +++ b/drivers/nvme/host/nvme.h > @@ -343,6 +343,7 @@ struct nvme_ctrl_ops { > unsigned int flags; > #define NVME_F_FABRICS (1 << 0) > #define NVME_F_METADATA_SUPPORTED (1 << 1) > +#define NVME_F_PCI_P2PDMA (1 << 2) > int (*reg_read32)(struct nvme_ctrl *ctrl, u32 off, u32 *val); > int (*reg_write32)(struct nvme_ctrl *ctrl, u32 off, u32 val); > int (*reg_read64)(struct nvme_ctrl *ctrl, u32 off, u64 *val); > diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c > index 2902585c6ddf..bb2120d30e39 100644 > +++ b/drivers/nvme/host/pci.c > @@ -737,8 +737,13 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, > struct request *req, > goto out; > > ret = BLK_STS_RESOURCE; > - nr_mapped = dma_map_sg_attrs(dev->dev, iod->sg, iod->nents, dma_dir, > - DMA_ATTR_NO_WARN); > + > + if (is_pci_p2pdma_page(sg_page(iod->sg))) > + nr_mapped = pci_p2pdma_map_sg(dev->dev, iod->sg, iod->nents, > + dma_dir); > + else > + nr_mapped = dma_map_sg_attrs(dev->dev, iod->sg, iod->nents, > + dma_dir, DMA_ATTR_NO_WARN); > if (!nr_mapped) > goto out; > > @@ -780,7 +785,10 @@ static void nvme_unmap_data(struct nvme_dev *dev, struct > request *req) > DMA_TO_DEVICE : DMA_FROM_DEVICE; > > if (iod->nents) { > - dma_unmap_sg(dev->dev, iod->sg, iod->nents, dma_dir); > + /* P2PDMA requests do not need to be unmapped */ > + if (!is_pci_p2pdma_page(sg_page(iod->sg))) > + dma_unmap_sg(dev->dev, iod->sg, iod->nents, dma_dir);
This seems like a poor direction, if we add IOMMU hairpin support we will need unmapping. Jason _______________________________________________ Linux-nvdimm mailing list [email protected] https://lists.01.org/mailman/listinfo/linux-nvdimm
