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-rw-r--r--block/blk-iolatency.c30
1 files changed, 16 insertions, 14 deletions
diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c
index 9568bf8dfe82..e285152345a2 100644
--- a/block/blk-iolatency.c
+++ b/block/blk-iolatency.c
@@ -401,7 +401,6 @@ static void check_scale_change(struct iolatency_grp *iolat)
unsigned int cur_cookie;
unsigned int our_cookie = atomic_read(&iolat->scale_cookie);
u64 scale_lat;
- unsigned int old;
int direction = 0;
if (lat_to_blkg(iolat)->parent == NULL)
@@ -422,11 +421,10 @@ static void check_scale_change(struct iolatency_grp *iolat)
else
return;
- old = atomic_cmpxchg(&iolat->scale_cookie, our_cookie, cur_cookie);
-
- /* Somebody beat us to the punch, just bail. */
- if (old != our_cookie)
+ if (!atomic_try_cmpxchg(&iolat->scale_cookie, &our_cookie, cur_cookie)) {
+ /* Somebody beat us to the punch, just bail. */
return;
+ }
if (direction < 0 && iolat->min_lat_nsec) {
u64 samples_thresh;
@@ -633,8 +631,8 @@ static void blkcg_iolatency_done_bio(struct rq_qos *rqos, struct bio *bio)
window_start = atomic64_read(&iolat->window_start);
if (now > window_start &&
(now - window_start) >= iolat->cur_win_nsec) {
- if (atomic64_cmpxchg(&iolat->window_start,
- window_start, now) == window_start)
+ if (atomic64_try_cmpxchg(&iolat->window_start,
+ &window_start, now))
iolatency_check_latencies(iolat, now);
}
}
@@ -773,19 +771,23 @@ int blk_iolatency_init(struct request_queue *q)
rqos->ops = &blkcg_iolatency_ops;
rqos->q = q;
- rq_qos_add(q, rqos);
-
+ ret = rq_qos_add(q, rqos);
+ if (ret)
+ goto err_free;
ret = blkcg_activate_policy(q, &blkcg_policy_iolatency);
- if (ret) {
- rq_qos_del(q, rqos);
- kfree(blkiolat);
- return ret;
- }
+ if (ret)
+ goto err_qos_del;
timer_setup(&blkiolat->timer, blkiolatency_timer_fn, 0);
INIT_WORK(&blkiolat->enable_work, blkiolatency_enable_work_fn);
return 0;
+
+err_qos_del:
+ rq_qos_del(q, rqos);
+err_free:
+ kfree(blkiolat);
+ return ret;
}
static void iolatency_set_min_lat_nsec(struct blkcg_gq *blkg, u64 val)