block: convert io-latency to use rq_qos_wait

Now that we have this common helper, convert io-latency over to use it
as well.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c
index 0b14c3d..bee0927 100644 (file)
--- a/block/blk-iolatency.c
+++ b/block/blk-iolatency.c
@@ -262,15 +262,15 @@ static inline void iolat_update_total_lat_avg(struct iolatency_grp *iolat,
                                   stat->rqs.mean);
 }
 
-static inline bool iolatency_may_queue(struct iolatency_grp *iolat,
-                                      wait_queue_entry_t *wait,
-                                      bool first_block)
+static void iolat_cleanup_cb(struct rq_wait *rqw, void *private_data)
 {
-       struct rq_wait *rqw = &iolat->rq_wait;
+       atomic_dec(&rqw->inflight);
+       wake_up(&rqw->wait);
+}
 
-       if (first_block && waitqueue_active(&rqw->wait) &&
-           rqw->wait.head.next != &wait->entry)
-               return false;
+static bool iolat_acquire_inflight(struct rq_wait *rqw, void *private_data)
+{
+       struct iolatency_grp *iolat = private_data;
        return rq_wait_inc_below(rqw, iolat->rq_depth.max_depth);
 }
 
@@ -281,8 +281,6 @@ static void __blkcg_iolatency_throttle(struct rq_qos *rqos,
 {
        struct rq_wait *rqw = &iolat->rq_wait;
        unsigned use_delay = atomic_read(&lat_to_blkg(iolat)->use_delay);
-       DEFINE_WAIT(wait);
-       bool first_block = true;
 
        if (use_delay)
                blkcg_schedule_throttle(rqos->q, use_memdelay);
@@ -299,20 +297,7 @@ static void __blkcg_iolatency_throttle(struct rq_qos *rqos,
                return;
        }
 
-       if (iolatency_may_queue(iolat, &wait, first_block))
-               return;
-
-       do {
-               prepare_to_wait_exclusive(&rqw->wait, &wait,
-                                         TASK_UNINTERRUPTIBLE);
-
-               if (iolatency_may_queue(iolat, &wait, first_block))
-                       break;
-               first_block = false;
-               io_schedule();
-       } while (1);
-
-       finish_wait(&rqw->wait, &wait);
+       rq_qos_wait(rqw, iolat, iolat_acquire_inflight, iolat_cleanup_cb);
 }
 
 #define SCALE_DOWN_FACTOR 2