[PATCH v10 08/12] cxl: Reject CXL Reset on multifunction devices

CXL Reset can be exposed as a PCI function reset method only when the
reset is function-scoped. PCI reset-method probing runs during
enumeration, so walking sibling functions there can race with functions
that have not been added to the bus yet.

Reject multifunction devices for now instead of trying to infer reset
scope from sibling state. Systems that can prove a multifunction device
has function-scoped CXL Reset can be enabled later.

Signed-off-by: Srirangan Madhavan <[email protected]>
---
 drivers/cxl/core/resource.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/cxl/core/resource.c b/drivers/cxl/core/resource.c
index 6d4528f77c53..464ca9bdae05 100644
--- a/drivers/cxl/core/resource.c
+++ b/drivers/cxl/core/resource.c
@@ -979,6 +979,9 @@ int cxl_reset_function(struct pci_dev *pdev, bool probe)
 	if (dvsec < 0)
 		return dvsec;
 
+	if (pdev->multifunction)
+		return -ENOTTY;
+
 	if (probe)
 		return 0;
 
-- 
2.43.0