It's possible to have buses without an associated bridge
(bus->self == NULL). SR-IOV can generate such buses. When
we find these, skip to the parent bus to look for the next
ACS test.
Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
---
David Ahern reported an oops from iommu drivers passing NULL into
this function for the same mistake. Harden this function against
assuming bus->self is valid as well. David, please include this
patch as well as the iommu patches in your testing.
drivers/pci/pci.c | 22 +++++++++++++++++-----
1 file changed, 17 insertions(+), 5 deletions(-)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index f3ea977..e11a49c 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2486,18 +2486,30 @@ bool pci_acs_enabled(struct pci_dev *pdev, u16 acs_flags)
bool pci_acs_path_enabled(struct pci_dev *start,
struct pci_dev *end, u16 acs_flags)
{
- struct pci_dev *pdev, *parent = start;
+ struct pci_dev *pdev = start;
+ struct pci_bus *bus;
do {
- pdev = parent;
-
if (!pci_acs_enabled(pdev, acs_flags))
return false;
- if (pci_is_root_bus(pdev->bus))
+ bus = pdev->bus;
+
+ if (pci_is_root_bus(bus))
return (end == NULL);
- parent = pdev->bus->self;
+ /*
+ * Skip buses without an associated bridge. In this
+ * case move to the parent and continue.
+ */
+ while (!bus->self) {
+ if (!pci_is_root_bus(bus))
+ bus = bus->parent;
+ else
+ return (end == NULL);
+ }
+
+ pdev = bus->self;
} while (pdev != end);
return true;
--
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