PCI/ACPI: Fix allocated memory release on error in pci_acpi_scan_root()

In the pci_acpi_scan_root() function, when creating a PCI bus fails,
we need to free up the previously allocated memory, which can avoid
invalid memory usage and save resources.

Fixes: 789befd ("arm64: PCI: Migrate ACPI related functions to pci-acpi.c")
Signed-off-by: Zhe Qiao <[email protected]>
[kwilczynski: commit log]
Signed-off-by: Krzysztof Wilczyński <[email protected]>
Acked-by: Rafael J. Wysocki <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: Zhe Qiao

drivers/pci/pci-acpi.c

@@ -1676,24 +1676,19 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
 		return NULL;
 
 	root_ops = kzalloc(sizeof(*root_ops), GFP_KERNEL);
-	if (!root_ops) {
-		kfree(ri);
-		return NULL;
-	}
+	if (!root_ops)
+		goto free_ri;
 
 	ri->cfg = pci_acpi_setup_ecam_mapping(root);
-	if (!ri->cfg) {
-		kfree(ri);
-		kfree(root_ops);
-		return NULL;
-	}
+	if (!ri->cfg)
+		goto free_root_ops;
 
 	root_ops->release_info = pci_acpi_generic_release_info;
 	root_ops->prepare_resources = pci_acpi_root_prepare_resources;
 	root_ops->pci_ops = (struct pci_ops *)&ri->cfg->ops->pci_ops;
 	bus = acpi_pci_root_create(root, root_ops, &ri->common, ri->cfg);
 	if (!bus)
-		return NULL;
+		goto free_cfg;
 
 	/* If we must preserve the resource configuration, claim now */
 	host = pci_find_host_bridge(bus);
@@ -1710,6 +1705,14 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
 		pcie_bus_configure_settings(child);
 
 	return bus;
+
+free_cfg:
+	pci_ecam_free(ri->cfg);
+free_root_ops:
+	kfree(root_ops);
+free_ri:
+	kfree(ri);
+	return NULL;
 }
 
 void pcibios_add_bus(struct pci_bus *bus)