diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
index 5c060b1..0474b02 100644
--- a/drivers/pci/setup-res.c
+++ b/drivers/pci/setup-res.c
@@ -263,6 +263,7 @@
 	resource_size_t align, size;
 	int ret;
 
+	res->flags |= IORESOURCE_UNSET;
 	align = pci_resource_alignment(dev, res);
 	if (!align) {
 		dev_info(&dev->dev, "BAR %d: can't assign %pR "
@@ -282,6 +283,7 @@
 		ret = pci_revert_fw_address(res, dev, resno, size);
 
 	if (!ret) {
+		res->flags &= ~IORESOURCE_UNSET;
 		res->flags &= ~IORESOURCE_STARTALIGN;
 		dev_info(&dev->dev, "BAR %d: assigned %pR\n", resno, res);
 		if (resno < PCI_BRIDGE_RESOURCES)
@@ -297,6 +299,7 @@
 	resource_size_t new_size;
 	int ret;
 
+	res->flags |= IORESOURCE_UNSET;
 	if (!res->parent) {
 		dev_info(&dev->dev, "BAR %d: can't reassign an unassigned resource %pR "
 			 "\n", resno, res);
@@ -307,6 +310,7 @@
 	new_size = resource_size(res) + addsize;
 	ret = _pci_assign_resource(dev, resno, new_size, min_align);
 	if (!ret) {
+		res->flags &= ~IORESOURCE_UNSET;
 		res->flags &= ~IORESOURCE_STARTALIGN;
 		dev_info(&dev->dev, "BAR %d: reassigned %pR\n", resno, res);
 		if (resno < PCI_BRIDGE_RESOURCES)