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>
---
 drivers/nvme/host/core.c |  4 ++++
 drivers/nvme/host/nvme.h |  1 +
 drivers/nvme/host/pci.c  | 18 ++++++++++++++----
 3 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 1e46e60b8f10..8a7caaa5ee49 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -2861,7 +2861,11 @@ 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_P2P)
+               queue_flag_set_unlocked(QUEUE_FLAG_PCI_P2P, ns->queue);
+
        ns->queue->queuedata = ns;
        ns->ctrl = ctrl;
 
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index ea1aa5283e8e..ae1453238250 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -286,6 +286,7 @@ struct nvme_ctrl_ops {
        unsigned int flags;
 #define NVME_F_FABRICS                 (1 << 0)
 #define NVME_F_METADATA_SUPPORTED      (1 << 1)
+#define NVME_F_PCI_P2P                 (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 71893babb982..29ef3fd24938 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -792,6 +792,7 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, 
struct request *req,
        enum dma_data_direction dma_dir = rq_data_dir(req) ?
                        DMA_TO_DEVICE : DMA_FROM_DEVICE;
        blk_status_t ret = BLK_STS_IOERR;
+       int nents;
 
        sg_init_table(iod->sg, blk_rq_nr_phys_segments(req));
        iod->nents = blk_rq_map_sg(q, req, iod->sg);
@@ -799,8 +800,13 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, 
struct request *req,
                goto out;
 
        ret = BLK_STS_RESOURCE;
-       if (!dma_map_sg_attrs(dev->dev, iod->sg, iod->nents, dma_dir,
-                               DMA_ATTR_NO_WARN))
+
+       if (REQ_IS_PCI_P2P(req))
+               nents = pci_p2pmem_map_sg(iod->sg, iod->nents);
+       else
+               nents = dma_map_sg_attrs(dev->dev, iod->sg, iod->nents,
+                                        dma_dir, DMA_ATTR_NO_WARN);
+       if (!nents)
                goto out;
 
        if (nvme_pci_use_sgls(dev, req))
@@ -844,7 +850,11 @@ 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_P2P(req))
+                       pci_p2pmem_unmap_sg(iod->sg, iod->nents);
+               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);
@@ -2417,7 +2427,7 @@ 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_P2P,
        .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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