block: make rq sector size accessible for block stats
Currently rq->data_len will be decreased by partial completion or
zeroed by completion, so when blk_stat_add() is invoked, data_len
will be zero and there will never be samples in poll_cb because
blk_mq_poll_stats_bkt() will return -1 if data_len is zero.
We could move blk_stat_add() back to __blk_mq_complete_request(),
but that would make the effort of trying to call ktime_get_ns()
once in vain. Instead we can reuse throtl_size field, and use
it for both block stats and block throttle, and adjust the
logic in blk_mq_poll_stats_bkt() accordingly.
Fixes: 4bc6339a583c ("block: move blk_stat_add() to __blk_mq_end_request()")
Tested-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 0445c99..18f773e 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -2248,7 +2248,8 @@ void blk_throtl_stat_add(struct request *rq, u64 time_ns)
struct request_queue *q = rq->q;
struct throtl_data *td = q->td;
- throtl_track_latency(td, rq->throtl_size, req_op(rq), time_ns >> 10);
+ throtl_track_latency(td, blk_rq_stats_sectors(rq), req_op(rq),
+ time_ns >> 10);
}
void blk_throtl_bio_endio(struct bio *bio)