tree f8688e775734e33e5616d916287e21f30147eb44
parent 89f3b6d62f2c7c1ed7b2e672be605016d9ff60f2
author Hou Tao <houtao1@huawei.com> 1558425543 +0800
committer Jens Axboe <axboe@kernel.dk> 1568584928 -0600

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>