blk-wbt: use wq_has_sleeper() for wq active check

BugLink: https://bugs.launchpad.net/bugs/1810998
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().

Tested-by: Anchal Agarwal <anchalag@amazon.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
(backported from commit b78820937b4762b7d30b807d7156bec1d89e4dd3)
[mfo: backport:
 - hunk 3: s/rq_wait_inc_below(rqw/atomic_inc_below(&rqw->inflight/]
Signed-off-by: Mauricio Faria de Oliveira <mfo@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

diff --git a/block/blk-wbt.c b/block/blk-wbt.c
index 0d3c01cfe30c94f0a9b218261807af6907b9d59b..036a676de09ce352d325b07f793226643b19b173 100644 (file)
--- a/block/blk-wbt.c
+++ b/block/blk-wbt.c
@@ -117,7 +117,7 @@ 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);
        }
 }
@@ -157,7 +157,7 @@ void __wbt_done(struct rq_wb *rwb, 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)
@@ -524,8 +524,8 @@ 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)
-               && atomic_inc_below(&rqw->inflight, get_limit(rwb, rw)))
+       if (!wq_has_sleeper(&rqw->wait) &&
+           atomic_inc_below(&rqw->inflight, get_limit(rwb, rw)))
                return;
 
        add_wait_queue_exclusive(&rqw->wait, &wait);