[PATCH 19/32] ACPICA: Namespace: Change namespace override to avoid node deletion.

Lv Zheng
2015-06-19T03:40:43Z

From: Bob Moore <robert.moore@intel.com>

ACPICA commit c0ce529e1fbb8ec47d2522a3aa10f3ab77e16e41

There is no reference counting implemented for struct acpi_namespace_node, so it
is currently not removable during runtime.
This patch changes the namespace override code to keep the old
struct acpi_namespace_node undeleted so that the override mechanism can happen
during runtime. Bob Moore.

Link: https://github.com/acpica/acpica/commit/c0ce529e
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
---
drivers/acpi/acpica/nssearch.c | 23 +++++++++++++++++++----
include/acpi/acpixf.h | 5 +++++
2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/drivers/acpi/acpica/nssearch.c b/drivers/acpi/acpica/nssearch.c
index 47fbe5b..d739040 100644
--- a/drivers/acpi/acpica/nssearch.c
+++ b/drivers/acpi/acpica/nssearch.c
@@ -331,13 +331,28 @@ acpi_ns_search_and_enter(u32 target_name,

/*
* If the namespace override feature is enabled for this node,
- * delete any existing node. This can only happen during the
- * boot stage, thus it is safe to remove the node here.
+ * delete any existing attached sub-object and make the node
+ * look like a new node that is owned by the override table.
*/
if (flags & ACPI_NS_OVERRIDE_IF_FOUND) {
+ ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
+ "Namespace override: %4.4s pass %u type %X Owner %X\n",
+ ACPI_CAST_PTR(char,
+ &target_name),
+ interpreter_mode,
+ (*return_node)->type,
+ walk_state->owner_id));
+
acpi_ns_delete_children(*return_node);
- acpi_ns_remove_node(*return_node);
- *return_node = ACPI_ENTRY_NOT_FOUND;
+ if (acpi_gbl_runtime_namespace_override) {
+ acpi_ut_remove_reference((*return_node)->object);
+ (*return_node)->object = NULL;
+ (*return_node)->owner_id =
+ walk_state->owner_id;
+ } else {
+ acpi_ns_remove_node(*return_node);
+ *return_node = ACPI_ENTRY_NOT_FOUND;
+ }
}

/* Return an error if we don't expect to find the object */
diff --git a/include/acpi/acpixf.h b/include/acpi/acpixf.h
index 00daa3c..33b4675 100644
--- a/include/acpi/acpixf.h
+++ b/include/acpi/acpixf.h
@@ -229,6 +229,11 @@ ACPI_INIT_GLOBAL(u8, acpi_gbl_disable_auto_repair, FALSE);
ACPI_INIT_GLOBAL(u8, acpi_gbl_disable_ssdt_table_install, FALSE);

/*
+ * Optionally enable runtime namespace override.
+ */
+ACPI_INIT_GLOBAL(u8, acpi_gbl_runtime_namespace_override, TRUE);
+
+/*
* We keep track of the latest version of Windows that has been requested by
* the BIOS. ACPI 5.0.
*/
--
1.7.10