2 files changed, 58 insertions, 82 deletions

diff --git a/drivers/acpi/glue.c b/drivers/acpi/glue.c
index a22a295edb69..ea77512ad70c 100644
--- a/drivers/acpi/glue.c
+++ b/drivers/acpi/glue.c
@@ -82,107 +82,80 @@ static struct acpi_bus_type *acpi_get_bus_type(struct device *dev)
 #define FIND_CHILD_MIN_SCORE    1
 #define FIND_CHILD_MAX_SCORE    2
 
-static acpi_status acpi_dev_present(acpi_handle handle, u32 lvl_not_used,
-                                  void *not_used, void **ret_p)
-{
-        struct acpi_device *adev = NULL;
-
-        acpi_bus_get_device(handle, &adev);
-        if (adev) {
-                *ret_p = handle;
-                return AE_CTRL_TERMINATE;
-        }
-        return AE_OK;
-}
-
-static int do_find_child_checks(acpi_handle handle, bool is_bridge)
+static int find_child_checks(struct acpi_device *adev, bool check_children)
 {
         bool sta_present = true;
         unsigned long long sta;
         acpi_status status;
 
-        status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
+        status = acpi_evaluate_integer(adev->handle, "_STA", NULL, &sta);
         if (status == AE_NOT_FOUND)
                 sta_present = false;
         else if (ACPI_FAILURE(status) || !(sta & ACPI_STA_DEVICE_ENABLED))
                 return -ENODEV;
 
-        if (is_bridge) {
-                void *test = NULL;
+        if (check_children && list_empty(&adev->children))
+                return -ENODEV;
 
-                /* Check if this object has at least one child device. */
-                acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
-                                    acpi_dev_present, NULL, NULL, &test);
-                if (!test)
-                        return -ENODEV;
-        }
         return sta_present ? FIND_CHILD_MAX_SCORE : FIND_CHILD_MIN_SCORE;
 }
 
-struct find_child_context {
-        u64 addr;
-        bool is_bridge;
-        acpi_handle ret;
-        int ret_score;
-};
-
-static acpi_status do_find_child(acpi_handle handle, u32 lvl_not_used,
-                                 void *data, void **not_used)
+struct acpi_device *acpi_find_child_device(struct acpi_device *parent,
+                                           u64 address, bool check_children)
 {
-        struct find_child_context *context = data;
-        unsigned long long addr;
-        acpi_status status;
-        int score;
-
-        status = acpi_evaluate_integer(handle, METHOD_NAME__ADR, NULL, &addr);
-        if (ACPI_FAILURE(status) || addr != context->addr)
-                return AE_OK;
-
-        if (!context->ret) {
-                /* This is the first matching object.  Save its handle. */
-                context->ret = handle;
-                return AE_OK;
-        }
-        /*
-         * There is more than one matching object with the same _ADR value.
-         * That really is unexpected, so we are kind of beyond the scope of the
-         * spec here.  We have to choose which one to return, though.
-         *
-         * First, check if the previously found object is good enough and return
-         * its handle if so.  Second, check the same for the object that we've
-         * just found.
-         */
-        if (!context->ret_score) {
-                score = do_find_child_checks(context->ret, context->is_bridge);
-                if (score == FIND_CHILD_MAX_SCORE)
-                        return AE_CTRL_TERMINATE;
-                else
-                        context->ret_score = score;
-        }
-        score = do_find_child_checks(handle, context->is_bridge);
-        if (score == FIND_CHILD_MAX_SCORE) {
-                context->ret = handle;
-                return AE_CTRL_TERMINATE;
-        } else if (score > context->ret_score) {
-                context->ret = handle;
-                context->ret_score = score;
+        struct acpi_device *adev, *ret = NULL;
+        int ret_score = 0;
+
+        list_for_each_entry(adev, &parent->children, node) {
+                unsigned long long addr;
+                acpi_status status;
+                int score;
+
+                status = acpi_evaluate_integer(adev->handle, METHOD_NAME__ADR,
+                                               NULL, &addr);
+                if (ACPI_FAILURE(status) || addr != address)
+                        continue;
+
+                if (!ret) {
+                        /* This is the first matching object.  Save it. */
+                        ret = adev;
+                        continue;
+                }
+                /*
+                 * There is more than one matching device object with the same
+                 * _ADR value.  That really is unexpected, so we are kind of
+                 * beyond the scope of the spec here.  We have to choose which
+                 * one to return, though.
+                 *
+                 * First, check if the previously found object is good enough
+                 * and return it if so.  Second, do the same for the object that
+                 * we've just found.
+                 */
+                if (!ret_score) {
+                        ret_score = find_child_checks(ret, check_children);
+                        if (ret_score == FIND_CHILD_MAX_SCORE)
+                                return ret;
+                }
+                score = find_child_checks(adev, check_children);
+                if (score == FIND_CHILD_MAX_SCORE) {
+                        return adev;
+                } else if (score > ret_score) {
+                        ret = adev;
+                        ret_score = score;
+                }
         }
-        return AE_OK;
+        return ret;
 }
 
-acpi_handle acpi_find_child(acpi_handle parent, u64 addr, bool is_bridge)
+acpi_handle acpi_find_child(acpi_handle handle, u64 addr, bool is_bridge)
 {
-        if (parent) {
-                struct find_child_context context = {
-                        .addr = addr,
-                        .is_bridge = is_bridge,
-                };
-
-                acpi_walk_namespace(ACPI_TYPE_DEVICE, parent, 1, do_find_child,
-                                    NULL, &context, NULL);
-                return context.ret;
-        }
-        return NULL;
+        struct acpi_device *adev;
+
+        if (!handle || acpi_bus_get_device(handle, &adev))
+                return NULL;
+
+        adev = acpi_find_child_device(adev, addr, is_bridge);
+        return adev ? adev->handle : NULL;
 }
 EXPORT_SYMBOL_GPL(acpi_find_child);
 
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index b241b733052e..6d82c5c14c0f 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -431,6 +431,9 @@ struct acpi_pci_root {
 };
 
 /* helper */
+
+struct acpi_device *acpi_find_child_device(struct acpi_device *parent,
+                                           u64 address, bool check_children);
 acpi_handle acpi_find_child(acpi_handle, u64, bool);
 static inline acpi_handle acpi_get_child(acpi_handle handle, u64 addr)
 {