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PCI/P2PDMA: Introduce configfs/sysfs enable attribute helpers

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Users of the P2PDMA infrastructure will typically need a way for the user
to tell the kernel to use P2P resources.  Typically this will be a simple
on/off boolean operation but sometimes it may be desirable for the user to
specify the exact device to use for the P2P operation.

Add new helpers for attributes which take a boolean or a PCI device.  Any
boolean as accepted by strtobool() turn P2P on or off (such as 'y', 'n',
'1', '0', etc).  Specifying a full PCI device name/BDF will select the
specific device.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Logan Gunthorpe
2018-10-04 15:27:38 -06:00
committed by Bjorn Helgaas
parent 977196b8c5
commit 2d7bc010f4
2 changed files with 97 additions and 0 deletions
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15
include/linux/pci-p2pdma.h
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@@ -32,6 +32,10 @@ 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(struct device *dev, struct scatterlist *sg, int nents,
enum dma_data_direction dir);
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,
bool use_p2pdma);
#else /* CONFIG_PCI_P2PDMA */
static inline int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar,
size_t size, u64 offset)
@@ -82,6 +86,17 @@ static inline int pci_p2pdma_map_sg(struct device *dev,
{
return 0;
}
static inline int pci_p2pdma_enable_store(const char *page,
struct pci_dev **p2p_dev, bool *use_p2pdma)
{
*use_p2pdma = false;
return 0;
}
static inline ssize_t pci_p2pdma_enable_show(char *page,
struct pci_dev *p2p_dev, bool use_p2pdma)
{
return sprintf(page, "none\n");
}
#endif /* CONFIG_PCI_P2PDMA */