diff --git a/block/blk-core.c b/block/blk-core.c index de771093b526..13b449df5ba0 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1083,6 +1083,7 @@ void blk_start_plug_nr_ios(struct blk_plug *plug, unsigned short nr_ios) if (tsk->plug) return; + plug->cur_ktime = 0; plug->mq_list = NULL; plug->cached_rq = NULL; plug->nr_ios = min_t(unsigned short, nr_ios, BLK_MAX_REQUEST_COUNT); diff --git a/block/blk.h b/block/blk.h index 79ae533cdf02..14bbc4b780f2 100644 --- a/block/blk.h +++ b/block/blk.h @@ -519,7 +519,19 @@ static inline int req_ref_read(struct request *req) static inline u64 blk_time_get_ns(void) { - return ktime_get_ns(); + struct blk_plug *plug = current->plug; + + if (!plug) + return ktime_get_ns(); + + /* + * 0 could very well be a valid time, but rather than flag "this is + * a valid timestamp" separately, just accept that we'll do an extra + * ktime_get_ns() if we just happen to get 0 as the current time. + */ + if (!plug->cur_ktime) + plug->cur_ktime = ktime_get_ns(); + return plug->cur_ktime; } static inline ktime_t blk_time_get(void) diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 99e4f5e72213..996d2ad756ff 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -942,6 +942,7 @@ struct blk_plug { /* if ios_left is > 1, we can batch tag/rq allocations */ struct request *cached_rq; + u64 cur_ktime; unsigned short nr_ios; unsigned short rq_count;