arm64: PCI: Manage controller-specific data on per-controller basis

Currently we use one shared global acpi_pci_root_ops structure to keep
controller-specific ops. We pass its pointer to acpi_pci_root_create() and
associate it with a host bridge instance for good. Such a design implies
serious drawback. Any potential manipulation on the single system-wide
acpi_pci_root_ops leads to kernel crash. The structure content is not
really changing even across multiple host bridges creation; thus it was not
an issue so far.

In preparation for adding ECAM quirks mechanism (where controller-specific
PCI ops may be different for each host bridge) allocate new
acpi_pci_root_ops and fill in with data for each bridge. Now it is safe to
have different controller-specific info. As a consequence free
acpi_pci_root_ops when host bridge is released.

No functional changes in this patch.

Signed-off-by: Tomasz Nowicki <[e-mail]>
Signed-off-by: Bjorn Helgaas <[e-mail]>
Acked-by: Lorenzo Pieralisi <[e-mail]>

arch/arm64/kernel/pci.c

···
 
 	ri = container_of(ci, struct acpi_pci_generic_root_info, common);
 	pci_ecam_free(ri->cfg);
+	kfree(ci->ops);
 	kfree(ri);
 }
-
-static struct acpi_pci_root_ops acpi_pci_root_ops = {
-	.release_info = pci_acpi_generic_release_info,
-};
 
 /* Interface called from ACPI code to setup PCI host controller */
 struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root)
···
 	int node = acpi_get_node(root->device->handle);
 	struct acpi_pci_generic_root_info *ri;
 	struct pci_bus *bus, *child;
+	struct acpi_pci_root_ops *root_ops;
 
 	ri = kzalloc_node(sizeof(*ri), GFP_KERNEL, node);
 	if (!ri)
 		return NULL;
 
+	root_ops = kzalloc_node(sizeof(*root_ops), GFP_KERNEL, node);
+	if (!root_ops)
+		return NULL;
+
 	ri->cfg = pci_acpi_setup_ecam_mapping(root);
 	if (!ri->cfg) {
 		kfree(ri);
+		kfree(root_ops);
 		return NULL;
 	}
 
-	acpi_pci_root_ops.pci_ops = &ri->cfg->ops->pci_ops;
-	bus = acpi_pci_root_create(root, &acpi_pci_root_ops, &ri->common,
-				   ri->cfg);
+	root_ops->release_info = pci_acpi_generic_release_info;
+	root_ops->pci_ops = &ri->cfg->ops->pci_ops;
+	bus = acpi_pci_root_create(root, root_ops, &ri->common, ri->cfg);
 	if (!bus)
 		return NULL;