blk_add_trace_unplug 1142 kernel/trace/blktrace.c 	ret = register_trace_block_unplug(blk_add_trace_unplug, NULL);
blk_add_trace_unplug 1157 kernel/trace/blktrace.c 	unregister_trace_block_unplug(blk_add_trace_unplug, NULL);