Merge tag 'kvm-ppc-fixes-5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git...

[linux-2.6-block.git] / block / blk-rq-qos.c

diff --git a/block/blk-rq-qos.c b/block/blk-rq-qos.c
index 659ccb8b693fa63cedfc53536589f5afcf3b1afc..3954c0dc14433d21c4baf7f9b007c2710fa67d64 100644 (file)
--- a/block/blk-rq-qos.c
+++ b/block/blk-rq-qos.c
@@ -202,6 +202,7 @@ static int rq_qos_wake_function(struct wait_queue_entry *curr,
                return -1;
 
        data->got_token = true;
+       smp_wmb();
        list_del_init(&curr->entry);
        wake_up_process(data->task);
        return 1;
@@ -244,7 +245,9 @@ void rq_qos_wait(struct rq_wait *rqw, void *private_data,
                return;
 
        prepare_to_wait_exclusive(&rqw->wait, &data.wq, TASK_UNINTERRUPTIBLE);
+       has_sleeper = !wq_has_single_sleeper(&rqw->wait);
        do {
+               /* The memory barrier in set_task_state saves us here. */
                if (data.got_token)
                        break;
                if (!has_sleeper && acquire_inflight_cb(rqw, private_data)) {
@@ -255,12 +258,14 @@ void rq_qos_wait(struct rq_wait *rqw, void *private_data,
                         * which means we now have two. Put our local token
                         * and wake anyone else potentially waiting for one.
                         */
+                       smp_rmb();
                        if (data.got_token)
                                cleanup_cb(rqw, private_data);
                        break;
                }
                io_schedule();
-               has_sleeper = false;
+               has_sleeper = true;
+               set_current_state(TASK_UNINTERRUPTIBLE);
        } while (1);
        finish_wait(&rqw->wait, &data.wq);
 }