For P2P requests, we must use the pci_p2pmem_[un]map_sg() functions
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 <log...@deltatee.com>
Reviewed-by: Sagi Grimberg <s...@grimberg.me>
---
 drivers/nvme/host/core.c |  4 ++++
 drivers/nvme/host/nvme.h |  1 +
 drivers/nvme/host/pci.c  | 19 +++++++++++++++----
 3 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 7aeca5db7916..c7c5de116720 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -2949,7 +2949,11 @@ 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;
+
        queue_flag_set_unlocked(QUEUE_FLAG_NONROT, ns->queue);
+       if (ctrl->ops->flags & NVME_F_PCI_P2PDMA)
+               queue_flag_set_unlocked(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 d733b14ede9d..1fb2b6603d49 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -290,6 +290,7 @@ 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 1fb57fa42dd0..0ebab7ab4d7e 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -796,8 +796,13 @@ 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 (REQ_IS_PCI_P2PDMA(req))
+               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;
 
@@ -842,7 +847,12 @@ 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);
+               if (REQ_IS_PCI_P2PDMA(req))
+                       pci_p2pdma_unmap_sg(dev->dev, iod->sg, iod->nents,
+                                           dma_dir);
+               else
+                       dma_unmap_sg(dev->dev, iod->sg, iod->nents, dma_dir);
+
                if (blk_integrity_rq(req)) {
                        if (req_op(req) == REQ_OP_READ)
                                nvme_dif_remap(req, nvme_dif_complete);
@@ -2426,7 +2436,8 @@ static int nvme_pci_reg_read64(struct nvme_ctrl *ctrl, 
u32 off, u64 *val)
 static const struct nvme_ctrl_ops nvme_pci_ctrl_ops = {
        .name                   = "pcie",
        .module                 = THIS_MODULE,
-       .flags                  = NVME_F_METADATA_SUPPORTED,
+       .flags                  = NVME_F_METADATA_SUPPORTED |
+                                 NVME_F_PCI_P2PDMA,
        .reg_read32             = nvme_pci_reg_read32,
        .reg_write32            = nvme_pci_reg_write32,
        .reg_read64             = nvme_pci_reg_read64,
-- 
2.11.0

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