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-rw-r--r--block/blk-mq.c68
1 files changed, 29 insertions, 39 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 22682fb4be65..5189cb1e478a 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -78,34 +78,32 @@ static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx *hctx,
static int blk_mq_queue_enter(struct request_queue *q)
{
- int ret;
-
- __percpu_counter_add(&q->mq_usage_counter, 1, 1000000);
- smp_mb();
-
- /* we have problems freezing the queue if it's initializing */
- if (!q->mq_freeze_depth)
- return 0;
-
- __percpu_counter_add(&q->mq_usage_counter, -1, 1000000);
+ while (true) {
+ int ret;
- spin_lock_irq(q->queue_lock);
- ret = wait_event_interruptible_lock_irq(q->mq_freeze_wq,
- !q->mq_freeze_depth || blk_queue_dying(q),
- *q->queue_lock);
- /* inc usage with lock hold to avoid freeze_queue runs here */
- if (!ret && !blk_queue_dying(q))
- __percpu_counter_add(&q->mq_usage_counter, 1, 1000000);
- else if (blk_queue_dying(q))
- ret = -ENODEV;
- spin_unlock_irq(q->queue_lock);
+ if (percpu_ref_tryget_live(&q->mq_usage_counter))
+ return 0;
- return ret;
+ ret = wait_event_interruptible(q->mq_freeze_wq,
+ !q->mq_freeze_depth || blk_queue_dying(q));
+ if (blk_queue_dying(q))
+ return -ENODEV;
+ if (ret)
+ return ret;
+ }
}
static void blk_mq_queue_exit(struct request_queue *q)
{
- __percpu_counter_add(&q->mq_usage_counter, -1, 1000000);
+ percpu_ref_put(&q->mq_usage_counter);
+}
+
+static void blk_mq_usage_counter_release(struct percpu_ref *ref)
+{
+ struct request_queue *q =
+ container_of(ref, struct request_queue, mq_usage_counter);
+
+ wake_up_all(&q->mq_freeze_wq);
}
/*
@@ -118,18 +116,9 @@ void blk_mq_freeze_queue(struct request_queue *q)
q->mq_freeze_depth++;
spin_unlock_irq(q->queue_lock);
- while (true) {
- s64 count;
-
- spin_lock_irq(q->queue_lock);
- count = percpu_counter_sum(&q->mq_usage_counter);
- spin_unlock_irq(q->queue_lock);
-
- if (count == 0)
- break;
- blk_mq_start_hw_queues(q);
- msleep(10);
- }
+ percpu_ref_kill(&q->mq_usage_counter);
+ blk_mq_run_queues(q, false);
+ wait_event(q->mq_freeze_wq, percpu_ref_is_zero(&q->mq_usage_counter));
}
static void blk_mq_unfreeze_queue(struct request_queue *q)
@@ -140,8 +129,10 @@ static void blk_mq_unfreeze_queue(struct request_queue *q)
wake = !--q->mq_freeze_depth;
WARN_ON_ONCE(q->mq_freeze_depth < 0);
spin_unlock_irq(q->queue_lock);
- if (wake)
+ if (wake) {
+ percpu_ref_reinit(&q->mq_usage_counter);
wake_up_all(&q->mq_freeze_wq);
+ }
}
bool blk_mq_can_queue(struct blk_mq_hw_ctx *hctx)
@@ -1785,7 +1776,7 @@ struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set)
if (!q)
goto err_hctxs;
- if (percpu_counter_init(&q->mq_usage_counter, 0))
+ if (percpu_ref_init(&q->mq_usage_counter, blk_mq_usage_counter_release))
goto err_map;
setup_timer(&q->timeout, blk_mq_rq_timer, (unsigned long) q);
@@ -1878,7 +1869,7 @@ void blk_mq_free_queue(struct request_queue *q)
blk_mq_exit_hw_queues(q, set, set->nr_hw_queues);
blk_mq_free_hw_queues(q, set);
- percpu_counter_destroy(&q->mq_usage_counter);
+ percpu_ref_exit(&q->mq_usage_counter);
free_percpu(q->queue_ctx);
kfree(q->queue_hw_ctx);
@@ -2037,8 +2028,7 @@ static int __init blk_mq_init(void)
{
blk_mq_cpu_init();
- /* Must be called after percpu_counter_hotcpu_callback() */
- hotcpu_notifier(blk_mq_queue_reinit_notify, -10);
+ hotcpu_notifier(blk_mq_queue_reinit_notify, 0);
return 0;
}