[PATCH 2/3] blk-wbt: use wq_has_sleeper() for wq active check

[Jens Axboe]

We need the memory barrier before checking the list head,
use the appropriate helper for this. The matching queue
side memory barrier is provided by set_current_state().

Signed-off-by: Jens Axboe <ax...@kernel.dk>
---
 block/blk-wbt.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/block/blk-wbt.c b/block/blk-wbt.c
index 1dd7edce7a99..853e22492f4e 100644
--- a/block/blk-wbt.c
+++ b/block/blk-wbt.c
@@ -118,7 +118,7 @@ static void rwb_wake_all(struct rq_wb *rwb)
        for (i = 0; i < WBT_NUM_RWQ; i++) {
                struct rq_wait *rqw = &rwb->rq_wait[i];
 
-               if (waitqueue_active(&rqw->wait))
+               if (wq_has_sleeper(&rqw->wait))
                        wake_up_all(&rqw->wait);
        }
 }
@@ -162,7 +162,7 @@ static void __wbt_done(struct rq_qos *rqos, enum wbt_flags 
wb_acct)
        if (inflight && inflight >= limit)
                return;
 
-       if (waitqueue_active(&rqw->wait)) {
+       if (wq_has_sleeper(&rqw->wait)) {
                int diff = limit - inflight;
 
                if (!inflight || diff >= rwb->wb_background / 2)
@@ -493,8 +493,8 @@ 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);
 
-       if (!waitqueue_active(&rqw->wait)
-               && rq_wait_inc_below(rqw, get_limit(rwb, rw)))
+       if (!wq_has_sleeper(&rqw->wait) &&
+           rq_wait_inc_below(rqw, get_limit(rwb, rw)))
                return;
 
        add_wait_queue_exclusive(&rqw->wait, &wait);
-- 
2.17.1