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nvme-pci: Add support for P2P memory in requests 

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 <logang@deltatee.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <keith.busch@intel.com>
This commit is contained in:
Logan Gunthorpe 2018-10-04 15:27:44 -06:00 committed by Bjorn Helgaas
parent 0f238ff5cc
commit e0596ab290
3 changed files with 18 additions and 4 deletions
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4
drivers/nvme/host/core.c
View File

@ -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;

1
drivers/nvme/host/nvme.h
View File

@ -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);

17
drivers/nvme/host/pci.c
View File

@ -745,8 +745,13 @@ 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;
@ -788,7 +793,10 @@ 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);
if (blk_integrity_rq(req))
dma_unmap_sg(dev->dev, &iod->meta_sg, 1, dma_dir);
}
@ -2400,7 +2408,8 @@ static int nvme_pci_get_address(struct nvme_ctrl *ctrl, char *buf, int size)
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,