block: wake up waiters when a queue is marked dying

[deliverable/linux.git] / block / blk-mq.c

diff --git a/block/blk-mq.c b/block/blk-mq.c
index da1ab5641227b670faac42a84fde7e223668a4d8..1a41d7aefbd57fe923e25c02835db5971838632b 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -107,7 +107,7 @@ static void blk_mq_usage_counter_release(struct percpu_ref *ref)
        wake_up_all(&q->mq_freeze_wq);
 }
 
-static void blk_mq_freeze_queue_start(struct request_queue *q)
+void blk_mq_freeze_queue_start(struct request_queue *q)
 {
        bool freeze;
 
@@ -120,6 +120,7 @@ static void blk_mq_freeze_queue_start(struct request_queue *q)
                blk_mq_run_queues(q, false);
        }
 }
+EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_start);
 
 static void blk_mq_freeze_queue_wait(struct request_queue *q)
 {
@@ -136,7 +137,7 @@ void blk_mq_freeze_queue(struct request_queue *q)
        blk_mq_freeze_queue_wait(q);
 }
 
-static void blk_mq_unfreeze_queue(struct request_queue *q)
+void blk_mq_unfreeze_queue(struct request_queue *q)
 {
        bool wake;
 
@@ -149,6 +150,17 @@ static void blk_mq_unfreeze_queue(struct request_queue *q)
                wake_up_all(&q->mq_freeze_wq);
        }
 }
+EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue);
+
+void blk_mq_wake_waiters(struct request_queue *q)
+{
+       struct blk_mq_hw_ctx *hctx;
+       unsigned int i;
+
+       queue_for_each_hw_ctx(q, hctx, i)
+               if (blk_mq_hw_queue_mapped(hctx))
+                       blk_mq_tag_wakeup_all(hctx->tags, true);
+}
 
 bool blk_mq_can_queue(struct blk_mq_hw_ctx *hctx)
 {
@@ -258,8 +270,10 @@ struct request *blk_mq_alloc_request(struct request_queue *q, int rw, gfp_t gfp,
                ctx = alloc_data.ctx;
        }
        blk_mq_put_ctx(ctx);
-       if (!rq)
+       if (!rq) {
+               blk_mq_queue_exit(q);
                return ERR_PTR(-EWOULDBLOCK);
+       }
        return rq;
 }
 EXPORT_SYMBOL(blk_mq_alloc_request);