[PATCH 09/14] PCI/P2PDMA: Introduce pci_p2pdma_unmap_sg()

Logan Gunthorpe
2019-07-22T23:10:05Z

Add pci_p2pdma_unmap_sg() to the two places that call
pci_p2pdma_map_sg().

This is a prep patch to introduce correct mappings for p2pdma
transactions that go through the root complex.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
---
drivers/infiniband/core/rw.c | 6 ++++--
drivers/nvme/host/pci.c | 6 ++++--
drivers/pci/p2pdma.c | 18 +++++++++++++++++-
include/linux/pci-p2pdma.h | 13 +++++++++++++
4 files changed, 38 insertions(+), 5 deletions(-)

diff --git a/drivers/infiniband/core/rw.c b/drivers/infiniband/core/rw.c
index dce06108c8c3..5337393d4dfe 100644
--- a/drivers/infiniband/core/rw.c
+++ b/drivers/infiniband/core/rw.c
@@ -583,8 +583,10 @@ void rdma_rw_ctx_destroy(struct rdma_rw_ctx *ctx, struct ib_qp *qp, u8 port_num,
break;
}

- /* P2PDMA contexts do not need to be unmapped */
- if (!is_pci_p2pdma_page(sg_page(sg)))
+ if (is_pci_p2pdma_page(sg_page(sg)))
+ pci_p2pdma_unmap_sg(qp->pd->device->dma_device, sg,
+ sg_cnt, dir);
+ else
ib_dma_unmap_sg(qp->pd->device, sg, sg_cnt, dir);
}
EXPORT_SYMBOL(rdma_rw_ctx_destroy);
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 7747712054cd..2348b15f6bd0 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -547,8 +547,10 @@ static void nvme_unmap_data(struct nvme_dev *dev, struct request *req)

WARN_ON_ONCE(!iod->nents);

- /* P2PDMA requests do not need to be unmapped */
- if (!is_pci_p2pdma_page(sg_page(iod->sg)))
+ if (is_pci_p2pdma_page(sg_page(iod->sg)))
+ pci_p2pdma_unmap_sg(dev->dev, iod->sg, iod->nents,
+ rq_dma_dir(req));
+ else
dma_unmap_sg(dev->dev, iod->sg, iod->nents, rq_dma_dir(req));

diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index ce361e287543..d3ced8eee30a 100644
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -793,7 +793,8 @@ EXPORT_SYMBOL_GPL(pci_p2pmem_publish);
* @dir: DMA direction
* @attrs: dma attributes passed to dma_map_sg() (if called)
*
- * Scatterlists mapped with this function should not be unmapped in any way.
+ * Scatterlists mapped with this function should be unmapped using
+ * pci_p2pdma_unmap_sg_attrs().
*
* Returns the number of SG entries mapped or 0 on error.
*/
@@ -827,6 +828,21 @@ int pci_p2pdma_map_sg_attrs(struct device *dev, struct scatterlist *sg,
}
EXPORT_SYMBOL_GPL(pci_p2pdma_map_sg_attrs);

+/**
+ * pci_p2pdma_unmap_sg - unmap a PCI peer-to-peer scatterlist that was
+ * mapped with pci_p2pdma_map_sg()
+ * @dev: device doing the DMA request
+ * @sg: scatter list to map
+ * @nents: number of elements returned by pci_p2pdma_map_sg()
+ * @dir: DMA direction
+ * @attrs: dma attributes passed to dma_unmap_sg() (if called)
+ */
+void pci_p2pdma_unmap_sg_attrs(struct device *dev, struct scatterlist *sg,
+ int nents, enum dma_data_direction dir, unsigned long attrs)
+{
+}
+EXPORT_SYMBOL_GPL(pci_p2pdma_unmap_sg_attrs);
+
/**
* pci_p2pdma_enable_store - parse a configfs/sysfs attribute store
* to enable p2pdma
diff --git a/include/linux/pci-p2pdma.h b/include/linux/pci-p2pdma.h
index 7fd51954f93a..8318a97c9c61 100644
--- a/include/linux/pci-p2pdma.h
+++ b/include/linux/pci-p2pdma.h
@@ -32,6 +32,8 @@ void pci_p2pmem_free_sgl(struct pci_dev *pdev, struct scatterlist *sgl);
void pci_p2pmem_publish(struct pci_dev *pdev, bool publish);
int pci_p2pdma_map_sg_attrs(struct device *dev, struct scatterlist *sg,
int nents, enum dma_data_direction dir, unsigned long attrs);
+void pci_p2pdma_unmap_sg_attrs(struct device *dev, struct scatterlist *sg,
+ int nents, enum dma_data_direction dir, unsigned long attrs);
int pci_p2pdma_enable_store(const char *page, struct pci_dev **p2p_dev,
bool *use_p2pdma);
ssize_t pci_p2pdma_enable_show(char *page, struct pci_dev *p2p_dev,
@@ -87,6 +89,11 @@ static inline int pci_p2pdma_map_sg_attrs(struct device *dev,
{
return 0;
}
+static inline void pci_p2pdma_unmap_sg_attrs(struct device *dev,
+ struct scatterlist *sg, int nents, enum dma_data_direction dir,
+ unsigned long attrs)
+{
+}
static inline int pci_p2pdma_enable_store(const char *page,
struct pci_dev **p2p_dev, bool *use_p2pdma)
{
@@ -118,4 +125,10 @@ static inline int pci_p2pdma_map_sg(struct device *dev, struct scatterlist *sg,
return pci_p2pdma_map_sg_attrs(dev, sg, nents, dir, 0);
}

+static inline void pci_p2pdma_unmap_sg(struct device *dev,
+ struct scatterlist *sg, int nents, enum dma_data_direction dir)
+{
+ pci_p2pdma_unmap_sg_attrs(dev, sg, nents, dir, 0);
+}
+
#endif /* _LINUX_PCI_P2P_H */
--
2.20.1