ACPICA: Allow same ACPI table to be loaded/unloaded more than once
Without this change, a table cannot be loaded again once it has
been loaded/unloaded one time. The current mechanism does not
unregister a table upon an unload. During a load, if the same
table is found, this no longer returns an exception.
http://www.acpica.org/bugzilla/show_bug.cgi?id=722
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/drivers/acpi/tables/tbinstal.c b/drivers/acpi/tables/tbinstal.c
index b22185f..905dc38 100644
--- a/drivers/acpi/tables/tbinstal.c
+++ b/drivers/acpi/tables/tbinstal.c
@@ -145,6 +145,8 @@
}
}
+ /* Check for a table match on the entire table length */
+
length = ACPI_MIN(table_desc->length,
acpi_gbl_root_table_list.tables[i].length);
if (ACPI_MEMCMP(table_desc->pointer,
@@ -153,17 +155,49 @@
continue;
}
- /* Table is already registered */
+ /*
+ * Note: the current mechanism does not unregister a table if it is
+ * dynamically unloaded. The related namespace entries are deleted,
+ * but the table remains in the root table list.
+ *
+ * The assumption here is that the number of different tables that
+ * will be loaded is actually small, and there is minimal overhead
+ * in just keeping the table in case it is needed again.
+ *
+ * If this assumption changes in the future (perhaps on large
+ * machines with many table load/unload operations), tables will
+ * need to be unregistered when they are unloaded, and slots in the
+ * root table list should be reused when empty.
+ */
+ /*
+ * Table is already registered.
+ * We can delete the table that was passed as a parameter.
+ */
acpi_tb_delete_table(table_desc);
*table_index = i;
- status = AE_ALREADY_EXISTS;
- goto release;
+
+ if (acpi_gbl_root_table_list.tables[i].
+ flags & ACPI_TABLE_IS_LOADED) {
+
+ /* Table is still loaded, this is an error */
+
+ status = AE_ALREADY_EXISTS;
+ goto release;
+ } else {
+ /* Table was unloaded, allow it to be reloaded */
+
+ table_desc->pointer =
+ acpi_gbl_root_table_list.tables[i].pointer;
+ table_desc->address =
+ acpi_gbl_root_table_list.tables[i].address;
+ status = AE_OK;
+ goto print_header;
+ }
}
- /*
- * Add the table to the global table list
- */
+ /* Add the table to the global root table list */
+
status = acpi_tb_store_table(table_desc->address, table_desc->pointer,
table_desc->length, table_desc->flags,
table_index);
@@ -171,6 +205,7 @@
goto release;
}
+ print_header:
acpi_tb_print_table_header(table_desc->address, table_desc->pointer);
release: