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PCI/P2PDMA: Store mapping method in an xarray

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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: 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 2019-08-12 11:30:45 -06:00 committed by Bjorn Helgaas
parent 142c242e6f
commit 110203bee0
1 changed files with 16 additions and 1 deletions
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17
drivers/pci/p2pdma.c
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@ -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 @@ check_b_path_acs:
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;
}