Symbol: blk_add_trace_zone_plug
kernel/trace/blktrace.c
1354
ret = register_trace_disk_zone_wplug_add_bio(blk_add_trace_zone_plug,
kernel/trace/blktrace.c
1380
unregister_trace_disk_zone_wplug_add_bio(blk_add_trace_zone_plug, NULL);