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Commit 110203be authored by Logan Gunthorpe's avatar Logan Gunthorpe Committed by Bjorn Helgaas
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PCI/P2PDMA: Store mapping method in an xarray 

When upstream_bridge_distance() is called, store the method required to map
the DMA transfers in an xarray so it can be looked up efficiently on the
hot path in pci_p2pdma_map_sg().

Link: https://lore.kernel.org/r/20190730163545.4915-12-logang@deltatee.com
Link: https://lore.kernel.org/r/20190812173048.9186-12-logang@deltatee.com


Signed-off-by: default avatarLogan Gunthorpe <logang@deltatee.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
parent 142c242e

drivers/pci/p2pdma.c

+16 −1
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#include <linux/random.h>

#include <linux/seq_buf.h>

#include <linux/iommu.h>

#include <linux/xarray.h>



enum pci_p2pdma_map_type {

	PCI_P2PDMA_MAP_UNKNOWN = 0,
@@ -30,6 +31,7 @@ enum pci_p2pdma_map_type { 
struct pci_p2pdma {

	struct gen_pool *pool;

	bool p2pmem_published;

	struct xarray map_types;

};



struct pci_p2pdma_pagemap {
@@ -105,6 +107,7 @@ static void pci_p2pdma_release(void *data) 


	gen_pool_destroy(p2pdma->pool);

	sysfs_remove_group(&pdev->dev.kobj, &p2pmem_group);

	xa_destroy(&p2pdma->map_types);

}



static int pci_p2pdma_setup(struct pci_dev *pdev)
@@ -116,6 +119,8 @@ static int pci_p2pdma_setup(struct pci_dev *pdev) 
	if (!p2p)

		return -ENOMEM;



	xa_init(&p2p->map_types);



	p2p->pool = gen_pool_create(PAGE_SHIFT, dev_to_node(&pdev->dev));

	if (!p2p->pool)

		goto out;
@@ -409,6 +414,12 @@ __upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client, 
	return PCI_P2PDMA_MAP_BUS_ADDR;

}



static unsigned long map_types_idx(struct pci_dev *client)

{

	return (pci_domain_nr(client->bus) << 16) |

		(client->bus->number << 8) | client->devfn;

}



/*

 * Find the distance through the nearest common upstream bridge between

 * two PCI devices.
@@ -459,9 +470,13 @@ upstream_bridge_distance(struct pci_dev *provider, struct pci_dev *client, 


	if (map_type == PCI_P2PDMA_MAP_THRU_HOST_BRIDGE) {

		if (!host_bridge_whitelist(provider, client))

			return PCI_P2PDMA_MAP_NOT_SUPPORTED;

			map_type = PCI_P2PDMA_MAP_NOT_SUPPORTED;

	}



	if (provider->p2pdma)

		xa_store(&provider->p2pdma->map_types, map_types_idx(client),

			 xa_mk_value(map_type), GFP_KERNEL);



	return map_type;

}