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| author | Logan Gunthorpe <logang@deltatee.com> | 2022-07-08 10:50:57 -0600 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2022-07-26 07:27:48 -0400 |
| commit | 159bf19270e80b5bc4b13aa88072dcb390b4d297 (patch) | |
| tree | 75717c2bb4987d1fa94fe913de87f7ab6460b5cb | |
| parent | f02ad36d4f76645e7e1c21f572260e9a2e61c26b (diff) | |
| download | lwn-159bf19270e80b5bc4b13aa88072dcb390b4d297.tar.gz lwn-159bf19270e80b5bc4b13aa88072dcb390b4d297.zip | |
dma-mapping: add flags to dma_map_ops to indicate PCI P2PDMA support
Add a flags member to the dma_map_ops structure with one flag to
indicate support for PCI P2PDMA.
Also, add a helper to check if a device supports PCI P2PDMA.
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
| -rw-r--r-- | include/linux/dma-map-ops.h | 10 | ||||
| -rw-r--r-- | include/linux/dma-mapping.h | 5 | ||||
| -rw-r--r-- | kernel/dma/mapping.c | 18 |
3 files changed, 33 insertions, 0 deletions
diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h index 99cec59dbfcb..010df04358aa 100644 --- a/include/linux/dma-map-ops.h +++ b/include/linux/dma-map-ops.h @@ -11,7 +11,17 @@ struct cma; +/* + * Values for struct dma_map_ops.flags: + * + * DMA_F_PCI_P2PDMA_SUPPORTED: Indicates the dma_map_ops implementation can + * handle PCI P2PDMA pages in the map_sg/unmap_sg operation. + */ +#define DMA_F_PCI_P2PDMA_SUPPORTED (1 << 0) + struct dma_map_ops { + unsigned int flags; + void *(*alloc)(struct device *dev, size_t size, dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs); diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index fe3849434b2a..25a30906289d 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -140,6 +140,7 @@ int dma_mmap_attrs(struct device *dev, struct vm_area_struct *vma, unsigned long attrs); bool dma_can_mmap(struct device *dev); int dma_supported(struct device *dev, u64 mask); +bool dma_pci_p2pdma_supported(struct device *dev); int dma_set_mask(struct device *dev, u64 mask); int dma_set_coherent_mask(struct device *dev, u64 mask); u64 dma_get_required_mask(struct device *dev); @@ -251,6 +252,10 @@ static inline int dma_supported(struct device *dev, u64 mask) { return 0; } +static inline bool dma_pci_p2pdma_supported(struct device *dev) +{ + return false; +} static inline int dma_set_mask(struct device *dev, u64 mask) { return -EIO; diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c index 746d46825d08..a9ce5d728231 100644 --- a/kernel/dma/mapping.c +++ b/kernel/dma/mapping.c @@ -723,6 +723,24 @@ int dma_supported(struct device *dev, u64 mask) } EXPORT_SYMBOL(dma_supported); +bool dma_pci_p2pdma_supported(struct device *dev) +{ + const struct dma_map_ops *ops = get_dma_ops(dev); + + /* if ops is not set, dma direct will be used which supports P2PDMA */ + if (!ops) + return true; + + /* + * Note: dma_ops_bypass is not checked here because P2PDMA should + * not be used with dma mapping ops that do not have support even + * if the specific device is bypassing them. + */ + + return ops->flags & DMA_F_PCI_P2PDMA_SUPPORTED; +} +EXPORT_SYMBOL_GPL(dma_pci_p2pdma_supported); + #ifdef CONFIG_ARCH_HAS_DMA_SET_MASK void arch_dma_set_mask(struct device *dev, u64 mask); #else |