We need to do this inside the loop as well, or we can allow new IO to supersede previous IO.
Signed-off-by: Jens Axboe <[email protected]> --- block/blk-wbt.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/block/blk-wbt.c b/block/blk-wbt.c index 853e22492f4e..c9358f1981fb 100644 --- a/block/blk-wbt.c +++ b/block/blk-wbt.c @@ -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); -- 2.17.1
