On 4/8/21 1:01 PM, Logan Gunthorpe wrote:
pci_p2pdma_map_type() will be needed by the dma-iommu map_sg
implementation because it will need to determine the mapping type
ahead of actually doing the mapping to create the actual iommu mapping.
Signed-off-by: Logan Gunthorpe <logang@xxxxxxxxxxxx>
---
drivers/pci/p2pdma.c | 34 +++++++++++++++++++++++-----------
include/linux/pci-p2pdma.h | 15 +++++++++++++++
2 files changed, 38 insertions(+), 11 deletions(-)
diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index bcb1a6d6119d..38c93f57a941 100644
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -20,13 +20,6 @@
#include <linux/seq_buf.h>
#include <linux/xarray.h>
-enum pci_p2pdma_map_type {
- PCI_P2PDMA_MAP_UNKNOWN = 0,
- PCI_P2PDMA_MAP_NOT_SUPPORTED,
- PCI_P2PDMA_MAP_BUS_ADDR,
- PCI_P2PDMA_MAP_THRU_HOST_BRIDGE,
-};
-
struct pci_p2pdma {
struct gen_pool *pool;
bool p2pmem_published;
@@ -822,13 +815,30 @@ void pci_p2pmem_publish(struct pci_dev *pdev, bool publish)
}
EXPORT_SYMBOL_GPL(pci_p2pmem_publish);
-static enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pgmap,
- struct device *dev)
+/**
+ * pci_p2pdma_map_type - return the type of mapping that should be used for
+ * a given device and pgmap
+ * @pgmap: the pagemap of a page to determine the mapping type for
+ * @dev: device that is mapping the page
+ * @dma_attrs: the attributes passed to the dma_map operation --
+ * this is so they can be checked to ensure P2PDMA pages were not
+ * introduced into an incorrect interface (like dma_map_sg). *
+ *
+ * Returns one of:
+ * PCI_P2PDMA_MAP_NOT_SUPPORTED - The mapping should not be done
+ * PCI_P2PDMA_MAP_BUS_ADDR - The mapping should use the PCI bus address
+ * PCI_P2PDMA_MAP_THRU_HOST_BRIDGE - The mapping should be done directly
+ */
I'd recommend putting these descriptions in the enum's in pci-p2pdma.h .
Also, can you use a better description for THRU_HOST_BRIDGE -- it leaves the reader wondering what 'done directly' means.
Thanks.
-dd
+enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pgmap,
+ struct device *dev, unsigned long dma_attrs)
{
struct pci_dev *provider = to_p2p_pgmap(pgmap)->provider;
enum pci_p2pdma_map_type ret;
struct pci_dev *client;
+ WARN_ONCE(!(dma_attrs & __DMA_ATTR_PCI_P2PDMA),
+ "PCI P2PDMA pages were mapped with dma_map_sg!");
+
if (!provider->p2pdma)
return PCI_P2PDMA_MAP_NOT_SUPPORTED;
@@ -879,7 +889,8 @@ int pci_p2pdma_map_sg_attrs(struct device *dev, struct scatterlist *sg,
struct pci_p2pdma_pagemap *p2p_pgmap =
to_p2p_pgmap(sg_page(sg)->pgmap);
- switch (pci_p2pdma_map_type(sg_page(sg)->pgmap, dev)) {
+ switch (pci_p2pdma_map_type(sg_page(sg)->pgmap, dev,
+ __DMA_ATTR_PCI_P2PDMA)) {
case PCI_P2PDMA_MAP_THRU_HOST_BRIDGE:
return dma_map_sg_attrs(dev, sg, nents, dir, attrs);
case PCI_P2PDMA_MAP_BUS_ADDR:
@@ -904,7 +915,8 @@ void pci_p2pdma_unmap_sg_attrs(struct device *dev, struct scatterlist *sg,
{
enum pci_p2pdma_map_type map_type;
- map_type = pci_p2pdma_map_type(sg_page(sg)->pgmap, dev);
+ map_type = pci_p2pdma_map_type(sg_page(sg)->pgmap, dev,
+ __DMA_ATTR_PCI_P2PDMA);
if (map_type == PCI_P2PDMA_MAP_THRU_HOST_BRIDGE)
dma_unmap_sg_attrs(dev, sg, nents, dir, attrs);
diff --git a/include/linux/pci-p2pdma.h b/include/linux/pci-p2pdma.h
index 8318a97c9c61..a06072ac3a52 100644
--- a/include/linux/pci-p2pdma.h
+++ b/include/linux/pci-p2pdma.h
@@ -16,6 +16,13 @@
struct block_device;
struct scatterlist;
+enum pci_p2pdma_map_type {
+ PCI_P2PDMA_MAP_UNKNOWN = 0,
+ PCI_P2PDMA_MAP_NOT_SUPPORTED,
+ PCI_P2PDMA_MAP_BUS_ADDR,
+ PCI_P2PDMA_MAP_THRU_HOST_BRIDGE,
+};
+
#ifdef CONFIG_PCI_P2PDMA
int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size,
u64 offset);
@@ -30,6 +37,8 @@ struct scatterlist *pci_p2pmem_alloc_sgl(struct pci_dev *pdev,
unsigned int *nents, u32 length);
void pci_p2pmem_free_sgl(struct pci_dev *pdev, struct scatterlist *sgl);
void pci_p2pmem_publish(struct pci_dev *pdev, bool publish);
+enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pgmap,
+ struct device *dev, unsigned long dma_attrs);
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,
@@ -83,6 +92,12 @@ static inline void pci_p2pmem_free_sgl(struct pci_dev *pdev,
static inline void pci_p2pmem_publish(struct pci_dev *pdev, bool publish)
{
}
+static inline enum pci_p2pdma_map_type pci_p2pdma_map_type(
+ struct dev_pagemap *pgmap, struct device *dev,
+ unsigned long dma_attrs)
+{
+ return PCI_P2PDMA_MAP_NOT_SUPPORTED;
+}
static inline int pci_p2pdma_map_sg_attrs(struct device *dev,
struct scatterlist *sg, int nents, enum dma_data_direction dir,
unsigned long attrs)
