[PATCH] ACPICA: Introduce acpi_load_table_with_index()

[Nikolaus Voss <nikolaus.voss@xxxxxxxxxxxxxxxxxxxxx>]

For unloading an ACPI table, it is necessary to provide the
index of the table. The method intended for dynamically
loading or hotplug addition of tables, acpi_load_table(),
does not provide this information, so a new function
acpi_load_table_with_index() with the same functionality,
but an optional pointer to the loaded table index is introduced.

The new function is used in the acpi_configfs driver to save the
index of the newly loaded table in order to unload it later.

Reported-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Fixes: d06c47e3dd07f ("ACPI: configfs: Resolve objects on host-directed table loads")
Signed-off-by: Nikolaus Voss <nikolaus.voss@xxxxxxxxxxxxxxxxxxxxx>
---
 drivers/acpi/acpi_configfs.c   |  2 +-
 drivers/acpi/acpica/tbxfload.c | 43 ++++++++++++++++++++++++++++++++++
 include/acpi/acpixf.h          |  6 +++++
 3 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/acpi_configfs.c b/drivers/acpi/acpi_configfs.c
index 57d9d574d4dd..9e77d5a266c0 100644
--- a/drivers/acpi/acpi_configfs.c
+++ b/drivers/acpi/acpi_configfs.c
@@ -53,7 +53,7 @@ static ssize_t acpi_table_aml_write(struct config_item *cfg,
 	if (!table->header)
 		return -ENOMEM;
 
-	ret = acpi_load_table(table->header);
+	ret = acpi_load_table_with_index(table->header, &table->index);
 	if (ret) {
 		kfree(table->header);
 		table->header = NULL;
diff --git a/drivers/acpi/acpica/tbxfload.c b/drivers/acpi/acpica/tbxfload.c
index 86f1693f6d29..7ea4fc879cb6 100644
--- a/drivers/acpi/acpica/tbxfload.c
+++ b/drivers/acpi/acpica/tbxfload.c
@@ -309,6 +309,49 @@ acpi_status acpi_load_table(struct acpi_table_header *table)
 
 ACPI_EXPORT_SYMBOL(acpi_load_table)
 
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_load_table_with_index
+ *
+ * PARAMETERS:  table               - Pointer to a buffer containing the ACPI
+ *                                    table to be loaded.
+ *              table_idx           - Pointer to a u32 for storing the table
+ *                                    index, might be NULL
+ * RETURN:      Status
+ *
+ * DESCRIPTION: see acpi_load_table() above. Additionally returns the index
+ *              of the newly created table in table_idx.
+ *
+ ******************************************************************************/
+acpi_status acpi_load_table_with_index(struct acpi_table_header *table,
+				       u32 *table_idx)
+{
+	acpi_status status;
+	u32 table_index;
+
+	ACPI_FUNCTION_TRACE(acpi_load_table_with_index);
+
+	/* Parameter validation */
+	if (!table)
+		return_ACPI_STATUS(AE_BAD_PARAMETER);
+
+	/* Install the table and load it into the namespace */
+	ACPI_INFO(("Host-directed Dynamic ACPI Table Load:"));
+	status = acpi_tb_install_and_load_table(
+		ACPI_PTR_TO_PHYSADDR(table), ACPI_TABLE_ORIGIN_EXTERNAL_VIRTUAL,
+		FALSE, &table_index);
+	if (table_idx)
+		*table_idx = table_index;
+
+	if (ACPI_SUCCESS(status)) {
+		/* Complete the initialization/resolution of new objects */
+		acpi_ns_initialize_objects();
+	}
+
+	return_ACPI_STATUS(status);
+}
+ACPI_EXPORT_SYMBOL(acpi_load_table_with_index)
+
 /*******************************************************************************
  *
  * FUNCTION:    acpi_unload_parent_table
diff --git a/include/acpi/acpixf.h b/include/acpi/acpixf.h
index e5e041413581..af375ab318de 100644
--- a/include/acpi/acpixf.h
+++ b/include/acpi/acpixf.h
@@ -460,6 +460,12 @@ ACPI_EXTERNAL_RETURN_STATUS(acpi_status ACPI_INIT_FUNCTION
 ACPI_EXTERNAL_RETURN_STATUS(acpi_status
 			    acpi_load_table(struct acpi_table_header *table))
 
+
+ACPI_EXTERNAL_RETURN_STATUS(acpi_status
+			    acpi_load_table_with_index(
+				    struct acpi_table_header *table,
+				    u32 *table_idx))
+
 ACPI_EXTERNAL_RETURN_STATUS(acpi_status
 			    acpi_unload_parent_table(acpi_handle object))
 
-- 
2.17.1