ACPI: Make acpi_bus_add() and acpi_bus_start() visibly different

The current ACPI namespace scanning code suggests that acpi_bus_add()
and acpi_bus_start() share some code.  In fact, however, they are
completely different code paths (except for the initial checks), so
refactor the code to make that distinction visibly clear.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Acked-by: Toshi Kani <toshi.kani@hp.com>

1 files changed, 35 insertions, 28 deletions

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index a7e81ac2cd0c..f3bcaf6c6bd4 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -1623,10 +1623,9 @@ static acpi_status acpi_bus_check_add(acpi_handle handle, u32 lvl,
         return AE_OK;
 }
 
-static acpi_status acpi_bus_probe_start(acpi_handle handle, u32 lvl,
-                                        void *context, void **not_used)
+static acpi_status acpi_bus_device_attach(acpi_handle handle, u32 lvl_not_used,
+                                          void *not_used, void **ret_not_used)
 {
-        struct acpi_bus_ops *ops = context;
         acpi_status status = AE_OK;
         struct acpi_device *device;
         unsigned long long sta_not_used;
@@ -1642,16 +1641,11 @@ static acpi_status acpi_bus_probe_start(acpi_handle handle, u32 lvl,
         if (acpi_bus_get_device(handle, &device))
                 return AE_CTRL_DEPTH;
 
-        if (ops->acpi_op_add) {
-                if (!acpi_match_device_ids(device, acpi_platform_device_ids)) {
-                        /* This is a known good platform device. */
-                        acpi_create_platform_device(device);
-                } else if (device_attach(&device->dev)) {
-                        status = AE_CTRL_DEPTH;
-                }
-        } else if (ops->acpi_op_start) {
-                if (ACPI_FAILURE(acpi_start_single_object(device)))
-                        status = AE_CTRL_DEPTH;
+        if (!acpi_match_device_ids(device, acpi_platform_device_ids)) {
+                /* This is a known good platform device. */
+                acpi_create_platform_device(device);
+        } else if (device_attach(&device->dev)) {
+                status = AE_CTRL_DEPTH;
         }
         return status;
 }
@@ -1672,10 +1666,10 @@ static int acpi_bus_scan(acpi_handle handle, struct acpi_bus_ops *ops,
                 goto out;
 
         ret = 0;
-        status = acpi_bus_probe_start(handle, 0, ops, NULL);
+        status = acpi_bus_device_attach(handle, 0, NULL, NULL);
         if (ACPI_SUCCESS(status))
                 acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX,
-                                    acpi_bus_probe_start, NULL, ops, NULL);
+                                    acpi_bus_device_attach, NULL, NULL, NULL);
 
  out:
         if (child)
@@ -1700,31 +1694,44 @@ int
 acpi_bus_add(struct acpi_device **child,
              struct acpi_device *parent, acpi_handle handle, int type)
 {
-        struct acpi_bus_ops ops;
-
-        memset(&ops, 0, sizeof(ops));
-        ops.acpi_op_add = 1;
+        struct acpi_bus_ops ops = { .acpi_op_add = 1, };
 
         return acpi_bus_scan(handle, &ops, child);
 }
 EXPORT_SYMBOL(acpi_bus_add);
 
-int acpi_bus_start(struct acpi_device *device)
+static acpi_status acpi_bus_start_device(acpi_handle handle, u32 lvl,
+                                         void *not_used, void **ret_not_used)
 {
-        struct acpi_bus_ops ops;
-        int result;
+        struct acpi_device *device;
+        unsigned long long sta_not_used;
+        int type_not_used;
+
+        /*
+         * Ignore errors ignored by acpi_bus_check_add() to avoid terminating
+         * namespace walks prematurely.
+         */
+        if (acpi_bus_type_and_status(handle, &type_not_used, &sta_not_used))
+                return AE_OK;
+
+        if (acpi_bus_get_device(handle, &device))
+                return AE_CTRL_DEPTH;
+
+        return acpi_start_single_object(device);
+}
 
+int acpi_bus_start(struct acpi_device *device)
+{
         if (!device)
                 return -EINVAL;
 
-        memset(&ops, 0, sizeof(ops));
-        ops.acpi_op_start = 1;
-
-        result = acpi_bus_scan(device->handle, &ops, NULL);
+        if (ACPI_SUCCESS(acpi_start_single_object(device)))
+                acpi_walk_namespace(ACPI_TYPE_ANY, device->handle,
+                                    ACPI_UINT32_MAX, acpi_bus_start_device,
+                                    NULL, NULL, NULL);
 
         acpi_update_all_gpes();
-
-        return result;
+        return 0;
 }
 EXPORT_SYMBOL(acpi_bus_start);