blk-wbt: fix has-sleeper queueing check

We need to do this inside the loop as well, or we can allow new
IO to supersede previous IO.

Tested-by: Anchal Agarwal <anchalag@amazon.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2018-08-20 13:22:27 -06:00
parent b78820937b
commit c45e6a037a

View file

@ -492,16 +492,17 @@ static void __wbt_wait(struct rq_wb *rwb, enum wbt_flags wb_acct,
{
struct rq_wait *rqw = get_rq_wait(rwb, wb_acct);
DECLARE_WAITQUEUE(wait, current);
bool has_sleeper;
if (!wq_has_sleeper(&rqw->wait) &&
rq_wait_inc_below(rqw, get_limit(rwb, rw)))
has_sleeper = wq_has_sleeper(&rqw->wait);
if (!has_sleeper && rq_wait_inc_below(rqw, get_limit(rwb, rw)))
return;
add_wait_queue_exclusive(&rqw->wait, &wait);
do {
set_current_state(TASK_UNINTERRUPTIBLE);
if (rq_wait_inc_below(rqw, get_limit(rwb, rw)))
if (!has_sleeper && rq_wait_inc_below(rqw, get_limit(rwb, rw)))
break;
if (lock) {
@ -510,6 +511,7 @@ static void __wbt_wait(struct rq_wb *rwb, enum wbt_flags wb_acct,
spin_lock_irq(lock);
} else
io_schedule();
has_sleeper = false;
} while (1);
__set_current_state(TASK_RUNNING);