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@xxxxxxxxxxxx Signed-off-by: Logan Gunthorpe <logang@xxxxxxxxxxxx> Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> --- drivers/pci/p2pdma.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index 771b45605853..db8224ff6e80 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -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; } -- 2.20.1
