Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux...

[linux-2.6-omap-h63xx.git] / drivers / acpi / acpica / nsxfeval.c

diff --git a/drivers/acpi/acpica/nsxfeval.c b/drivers/acpi/acpica/nsxfeval.c
index 22a7171ac1ed5888d0642e4ba20315d5b0a61d2a..045054037c2d2684f95e87b29e02088cd9a7dc66 100644 (file)
--- a/drivers/acpi/acpica/nsxfeval.c
+++ b/drivers/acpi/acpica/nsxfeval.c
@@ -387,8 +387,7 @@ static void acpi_ns_resolve_references(struct acpi_evaluate_info *info)
 
        /* We are interested in reference objects only */
 
-       if (ACPI_GET_OBJECT_TYPE(info->return_object) !=
-           ACPI_TYPE_LOCAL_REFERENCE) {
+       if ((info->return_object)->common.type != ACPI_TYPE_LOCAL_REFERENCE) {
                return;
        }
 
@@ -476,21 +475,40 @@ acpi_walk_namespace(acpi_object_type type,
        }
 
        /*
-        * Lock the namespace around the walk.
-        * The namespace will be unlocked/locked around each call
-        * to the user function - since this function
-        * must be allowed to make Acpi calls itself.
+        * Need to acquire the namespace reader lock to prevent interference
+        * with any concurrent table unloads (which causes the deletion of
+        * namespace objects). We cannot allow the deletion of a namespace node
+        * while the user function is using it. The exception to this are the
+        * nodes created and deleted during control method execution -- these
+        * nodes are marked as temporary nodes and are ignored by the namespace
+        * walk. Thus, control methods can be executed while holding the
+        * namespace deletion lock (and the user function can execute control
+        * methods.)
+        */
+       status = acpi_ut_acquire_read_lock(&acpi_gbl_namespace_rw_lock);
+       if (ACPI_FAILURE(status)) {
+               return status;
+       }
+
+       /*
+        * Lock the namespace around the walk. The namespace will be
+        * unlocked/locked around each call to the user function - since the user
+        * function must be allowed to make ACPICA calls itself (for example, it
+        * will typically execute control methods during device enumeration.)
         */
        status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
        if (ACPI_FAILURE(status)) {
-               return_ACPI_STATUS(status);
+               goto unlock_and_exit;
        }
 
        status = acpi_ns_walk_namespace(type, start_object, max_depth,
-                                       ACPI_NS_WALK_UNLOCK,
-                                       user_function, context, return_value);
+                                       ACPI_NS_WALK_UNLOCK, user_function,
+                                       context, return_value);
 
        (void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
+
+      unlock_and_exit:
+       (void)acpi_ut_release_read_lock(&acpi_gbl_namespace_rw_lock);
        return_ACPI_STATUS(status);
 }