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path: root/drivers/acpi/acpica/nsxfeval.c
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Diffstat (limited to 'drivers/acpi/acpica/nsxfeval.c')
-rw-r--r--drivers/acpi/acpica/nsxfeval.c36
1 files changed, 27 insertions, 9 deletions
diff --git a/drivers/acpi/acpica/nsxfeval.c b/drivers/acpi/acpica/nsxfeval.c
index 22a7171ac1e..045054037c2 100644
--- 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);
}