[PATCH 2/2] PCI: Lock bus while iterating devices on it

[Imre Deak]

Based on a patch from Dan Williams:
https://lore.kernel.org/all/6657833b3b5ae_14984b29437@dwillia2-xfh.jf.intel.com.notmuch/

Signed-off-by: Imre Deak <imre.deak at intel.com>
---
 drivers/pci/pci.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 8df32a3a0979d..aac5daad3188a 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -5444,6 +5444,7 @@ static void pci_bus_lock(struct pci_bus *bus)
 {
 	struct pci_dev *dev;
 
+	pci_dev_lock(bus->self);
 	list_for_each_entry(dev, &bus->devices, bus_list) {
 		pci_dev_lock(dev);
 		if (dev->subordinate)
@@ -5461,6 +5462,7 @@ static void pci_bus_unlock(struct pci_bus *bus)
 			pci_bus_unlock(dev->subordinate);
 		pci_dev_unlock(dev);
 	}
+	pci_dev_unlock(bus->self);
 }
 
 /* Return 1 on successful lock, 0 on contention */
@@ -5468,6 +5470,7 @@ static int pci_bus_trylock(struct pci_bus *bus)
 {
 	struct pci_dev *dev;
 
+	pci_dev_lock(bus->self);
 	list_for_each_entry(dev, &bus->devices, bus_list) {
 		if (!pci_dev_trylock(dev))
 			goto unlock;
@@ -5486,6 +5489,7 @@ static int pci_bus_trylock(struct pci_bus *bus)
 			pci_bus_unlock(dev->subordinate);
 		pci_dev_unlock(dev);
 	}
+	pci_dev_unlock(bus->self);
 	return 0;
 }
 
-- 
2.43.3