[PATCH 3.12 10/56] PCI: Add pci_upstream_bridge()

[Jiri Slaby]

From: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

commit c6bde215acfd637708142ae671843b6f0eadbc6d upstream.

This adds a pci_upstream_bridge() interface to find the PCI-to-PCI bridge
upstream from a device.  This is typically just "dev->bus->self", but in
the case of a VF on a virtual bus, we have to start from the corresponding
PF.  Returns NULL if there is no upstream PCI bridge, i.e., if the device
is on a root bus.

Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Acked-by: Yinghai Lu <yinghai@xxxxxxxxxx>

Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
 include/linux/pci.h | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/include/linux/pci.h b/include/linux/pci.h
index da172f956ad6..db4ce115705e 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -478,6 +478,15 @@ static inline bool pci_is_root_bus(struct pci_bus *pbus)
 	return !(pbus->parent);
 }
 
+static inline struct pci_dev *pci_upstream_bridge(struct pci_dev *dev)
+{
+	dev = pci_physfn(dev);
+	if (pci_is_root_bus(dev->bus))
+		return NULL;
+
+	return dev->bus->self;
+}
+
 #ifdef CONFIG_PCI_MSI
 static inline bool pci_dev_msi_enabled(struct pci_dev *pci_dev)
 {
-- 
2.1.0

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