blk_trace_startstop  539 block/blktrace.c 		ret = blk_trace_startstop(q, start);
blk_trace_startstop  561 block/blktrace.c 		blk_trace_startstop(q, 0);
blk_trace_startstop  322 include/linux/blktrace_api.h extern int blk_trace_startstop(struct request_queue *q, int start);