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Merge branch 'pci/p2pdma'

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- Update pci_p2pdma_whitelist[] checking so we accept Skylake-E Root Ports
  even if they're not at devfn 00.0 (Shlomo Pongratz)

* pci/p2pdma:
  PCI/P2PDMA: Whitelist Intel Skylake-E Root Ports at any devfn
This commit is contained in:
Bjorn Helgaas 2022-05-24 16:42:22 -05:00
commit 4f5bc91ce1
1 changed files with 15 additions and 10 deletions
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25
drivers/pci/p2pdma.c
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@ -326,15 +326,16 @@ static const struct pci_p2pdma_whitelist_entry {
};
/*
* This lookup function tries to find the PCI device corresponding to a given
* host bridge.
* If the first device on host's root bus is either devfn 00.0 or a PCIe
* Root Port, return it. Otherwise return NULL.
*
* It assumes the host bridge device is the first PCI device in the
* bus->devices list and that the devfn is 00.0. These assumptions should hold
* for all the devices in the whitelist above.
* We often use a devfn 00.0 "host bridge" in the pci_p2pdma_whitelist[]
* (though there is no PCI/PCIe requirement for such a device). On some
* platforms, e.g., Intel Skylake, there is no such host bridge device, and
* pci_p2pdma_whitelist[] may contain a Root Port at any devfn.
*
* This function is equivalent to pci_get_slot(host->bus, 0), however it does
* not take the pci_bus_sem lock seeing __host_bridge_whitelist() must not
* This function is similar to pci_get_slot(host->bus, 0), but it does
* not take the pci_bus_sem lock since __host_bridge_whitelist() must not
* sleep.
*
* For this to be safe, the caller should hold a reference to a device on the
@ -350,10 +351,14 @@ static struct pci_dev *pci_host_bridge_dev(struct pci_host_bridge *host)
if (!root)
return NULL;
if (root->devfn != PCI_DEVFN(0, 0))
return NULL;
return root;
if (root->devfn == PCI_DEVFN(0, 0))
return root;
if (pci_pcie_type(root) == PCI_EXP_TYPE_ROOT_PORT)
return root;
return NULL;
}
static bool __host_bridge_whitelist(struct pci_host_bridge *host,