Add a pci_dev_depth() helper function, which returns the depth
of a device in the PCI hierarchy.
This is useful to have for lockdep annotations for dealing with
nested locked when traversing the hierarchy.
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
include/linux/pci.h | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 7d825637d7ca..6ad78cc67aa8 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -691,6 +691,26 @@ static inline bool pci_is_bridge(struct pci_dev *dev)
dev->hdr_type == PCI_HEADER_TYPE_CARDBUS;
}
+/**
+ * pci_dev_depth - Return the depth of a device in the PCI hierarchy
+ * @dev: PCI device
+ *
+ * Return the depth (number of parent busses above) the device in
+ * the PCI hierarchy.
+ */
+static inline int pci_dev_depth(struct pci_dev *dev)
+{
+ struct pci_bus *bus = dev->bus;
+ int depth = 0;
+
+ while (bus->parent) {
+ depth++;
+ bus = bus->parent;
+ }
+
+ return depth;
+}
+
#define for_each_pci_bridge(dev, bus) \
list_for_each_entry(dev, &bus->devices, bus_list) \
if (!pci_is_bridge(dev)) {} else
--
2.33.1
