Commit 159bf192 authored by Logan Gunthorpe's avatar Logan Gunthorpe Committed by Christoph Hellwig
Browse files

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: default avatarLogan Gunthorpe <logang@deltatee.com>
Reviewed-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent f02ad36d

include/linux/dma-map-ops.h

+10 −0
Original line number Diff line number Diff line
@@ -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);

include/linux/dma-mapping.h

+5 −0
Original line number Diff line number Diff line
@@ -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;

kernel/dma/mapping.c

+18 −0
Original line number Diff line number Diff line
@@ -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