creation of blktrace completion messages

Hi all, where does the kernel create the blktrace completion messages? Is it done in the interrupt routine or in the block layer. I just found: register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL); and register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL); But I don't find the corresponding functions. Thanks, Matthias --- http://motzblog.wordpress.com/