diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index f30ca75..cfab2c7 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -1923,6 +1923,67 @@ void pci_assign_unassigned_bridge_resources(struct pci_dev *bridge)
 }
 EXPORT_SYMBOL_GPL(pci_assign_unassigned_bridge_resources);
 
+int pci_reassign_bridge_resources(struct pci_dev *bridge, unsigned long type)
+{
+	const unsigned long type_mask = IORESOURCE_IO | IORESOURCE_MEM |
+		IORESOURCE_PREFETCH | IORESOURCE_MEM_64;
+
+	struct resource saved;
+	LIST_HEAD(add_list);
+	LIST_HEAD(fail_head);
+	struct pci_dev_resource *fail_res;
+	unsigned i;
+	int ret = 0;
+
+	/* Release all children from the matching bridge resource */
+	for (i = PCI_BRIDGE_RESOURCES; i < PCI_BRIDGE_RESOURCE_END; ++i) {
+		struct resource *res = &bridge->resource[i];
+
+		if ((res->flags & type_mask) != (type & type_mask))
+			continue;
+
+		saved = *res;
+		if (res->parent) {
+			release_child_resources(res);
+			release_resource(res);
+		}
+		res->start = 0;
+		res->end = 0;
+		break;
+	}
+
+	if (i == PCI_BRIDGE_RESOURCE_END)
+		return -ENOENT;
+
+	__pci_bus_size_bridges(bridge->subordinate, &add_list);
+	__pci_bridge_assign_resources(bridge, &add_list, &fail_head);
+	BUG_ON(!list_empty(&add_list));
+
+	/* restore size and flags */
+	list_for_each_entry(fail_res, &fail_head, list) {
+		struct resource *res = fail_res->res;
+
+		res->start = fail_res->start;
+		res->end = fail_res->end;
+		res->flags = fail_res->flags;
+	}
+
+	/* Revert to the old configuration */
+	if (!list_empty(&fail_head)) {
+		struct resource *res = &bridge->resource[i];
+
+		res->start = saved.start;
+		res->end = saved.end;
+		res->flags = saved.flags;
+
+		pci_claim_resource(bridge, i);
+		ret = -ENOSPC;
+	}
+
+	free_list(&fail_head);
+	return ret;
+}
+
 void pci_assign_unassigned_bus_resources(struct pci_bus *bus)
 {
 	struct pci_dev *dev;
diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
index 9526e34..d03e6f1 100644
--- a/drivers/pci/setup-res.c
+++ b/drivers/pci/setup-res.c
@@ -363,6 +363,51 @@ int pci_reassign_resource(struct pci_dev *dev, int resno, resource_size_t addsiz
 	return 0;
 }
 
+int pci_resize_resource(struct pci_dev *dev, int resno, int size)
+{
+	struct resource *res = dev->resource + resno;
+	u32 sizes = pci_rbar_get_sizes(dev, resno);
+	int old = pci_rbar_get_size(dev, resno);
+	u64 bytes = 1ULL << (size + 20);
+	int ret = 0;
+
+	if (!sizes)
+		return -ENOTSUPP;
+
+	if (!(sizes & (1 << size)))
+		return -EINVAL;
+
+	if (old < 0)
+		return old;
+
+	/* Make sure the resource isn't assigned before making it larger. */
+	if (resource_size(res) < bytes && res->parent) {
+		release_resource(res);
+		res->end = resource_size(res) - 1;
+		res->start = 0;
+		if (resno < PCI_BRIDGE_RESOURCES)
+			pci_update_resource(dev, resno);
+	}
+
+	if (pci_rbar_set_size(dev, resno, size))
+		res->end = res->start + bytes - 1;
+	else
+		return -EIO;
+
+	ret = pci_reassign_bridge_resources(dev->bus->self, res->flags);
+	if (ret) {
+		pci_rbar_set_size(dev, resno, old);
+		res->end = res->start + (1ULL << (old + 20)) - 1;
+
+		pci_assign_unassigned_bus_resources(dev->bus);
+		pci_setup_bridge(dev->bus);
+	}
+
+	pci_reenable_device(dev->bus->self);
+	return ret;
+}
+EXPORT_SYMBOL(pci_resize_resource);
+
 int pci_enable_resources(struct pci_dev *dev, int mask)
 {
 	u16 cmd, old_cmd;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 9f26ca4..c85d8d7 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1055,6 +1055,7 @@ void pci_reset_bridge_secondary_bus(struct pci_dev *dev);
 void pci_update_resource(struct pci_dev *dev, int resno);
 int __must_check pci_assign_resource(struct pci_dev *dev, int i);
 int __must_check pci_reassign_resource(struct pci_dev *dev, int i, resource_size_t add_size, resource_size_t align);
+int __must_check pci_resize_resource(struct pci_dev *dev, int i, int size);
 int pci_select_bars(struct pci_dev *dev, unsigned long flags);
 bool pci_device_is_present(struct pci_dev *pdev);
 void pci_ignore_hotplug(struct pci_dev *dev);
@@ -1135,6 +1136,7 @@ void pci_assign_unassigned_resources(void);
 void pci_assign_unassigned_bridge_resources(struct pci_dev *bridge);
 void pci_assign_unassigned_bus_resources(struct pci_bus *bus);
 void pci_assign_unassigned_root_bus_resources(struct pci_bus *bus);
+int pci_reassign_bridge_resources(struct pci_dev *bridge, unsigned long type);
 void pdev_enable_device(struct pci_dev *);
 int pci_enable_resources(struct pci_dev *, int mask);
 void pci_fixup_irqs(u8 (*)(struct pci_dev *, u8 *),
