PCI/ACPI: Remove unused global list acpi_pci_roots

Now the global list acpi_pci_roots pci_root.c is useless, remove it.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Len Brown <lenb@kernel.org>
diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 852fb96..18b7ab2 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -65,10 +65,6 @@
 	.detach = acpi_pci_root_remove,
 };
 
-/* Lock to protect both acpi_pci_roots lists */
-static DEFINE_MUTEX(acpi_pci_root_lock);
-static LIST_HEAD(acpi_pci_roots);
-
 static DEFINE_MUTEX(osc_lock);
 
 /**
@@ -423,7 +419,6 @@
 		}
 	}
 
-	INIT_LIST_HEAD(&root->node);
 	root->device = device;
 	root->segment = segment & 0xFFFF;
 	strcpy(acpi_device_name(device), ACPI_PCI_ROOT_DEVICE_NAME);
@@ -447,10 +442,6 @@
 	 * TBD: Need PCI interface for enumeration/configuration of roots.
 	 */
 
-	mutex_lock(&acpi_pci_root_lock);
-	list_add_tail(&root->node, &acpi_pci_roots);
-	mutex_unlock(&acpi_pci_root_lock);
-
 	/*
 	 * Scan the Root Bridge
 	 * --------------------
@@ -464,7 +455,7 @@
 			    "Bus %04x:%02x not present in PCI namespace\n",
 			    root->segment, (unsigned int)root->secondary.start);
 		result = -ENODEV;
-		goto out_del_root;
+		goto end;
 	}
 
 	/* Indicate support for various _OSC capabilities. */
@@ -545,11 +536,6 @@
 	pci_bus_add_devices(root->bus);
 	return 1;
 
-out_del_root:
-	mutex_lock(&acpi_pci_root_lock);
-	list_del(&root->node);
-	mutex_unlock(&acpi_pci_root_lock);
-
 end:
 	kfree(root);
 	return result;
@@ -566,9 +552,6 @@
 
 	pci_remove_root_bus(root->bus);
 
-	mutex_lock(&acpi_pci_root_lock);
-	list_del(&root->node);
-	mutex_unlock(&acpi_pci_root_lock);
 	kfree(root);
 }
 
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 98db31d..af0f840 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -472,7 +472,6 @@
 int unregister_acpi_bus_type(struct acpi_bus_type *);
 
 struct acpi_pci_root {
-	struct list_head node;
 	struct acpi_device * device;
 	struct pci_bus *bus;
 	u16 segment;