1 files changed, 31 insertions, 11 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index 7e9715a..e1fcf7a 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -217,7 +217,7 @@ static void blk_delay_work(struct work_struct *work)
 
 	q = container_of(work, struct request_queue, delay_work.work);
 	spin_lock_irq(q->queue_lock);
-	__blk_run_queue(q);
+	__blk_run_queue(q, false);
 	spin_unlock_irq(q->queue_lock);
 }
 
@@ -251,7 +251,7 @@ void blk_start_queue(struct request_queue *q)
 	WARN_ON(!irqs_disabled());
 
 	queue_flag_clear(QUEUE_FLAG_STOPPED, q);
-	__blk_run_queue(q);
+	__blk_run_queue(q, false);
 }
 EXPORT_SYMBOL(blk_start_queue);
 
@@ -289,11 +289,14 @@ EXPORT_SYMBOL(blk_stop_queue);
  *     that its ->make_request_fn will not re-add plugging prior to calling
  *     this function.
  *
+ *     This function does not cancel any asynchronous activity arising
+ *     out of elevator or throttling code. That would require elevaotor_exit()
+ *     and blk_throtl_exit() to be called with queue lock initialized.
+ *
  */
 void blk_sync_queue(struct request_queue *q)
 {
 	del_timer_sync(&q->timeout);
-	throtl_shutdown_timer_wq(q);
 	cancel_delayed_work_sync(&q->delay_work);
 	queue_sync_plugs(q);
 }
@@ -302,13 +305,14 @@ EXPORT_SYMBOL(blk_sync_queue);
 /**
  * __blk_run_queue - run a single device queue
  * @q:	The queue to run
+ * @force_kblockd: Don't run @q->request_fn directly.  Use kblockd.
  *
  * Description:
  *    See @blk_run_queue. This variant must be called with the queue lock
  *    held and interrupts disabled.
  *
  */
-void __blk_run_queue(struct request_queue *q)
+void __blk_run_queue(struct request_queue *q, bool force_kblockd)
 {
 	if (unlikely(blk_queue_stopped(q)))
 		return;
@@ -317,7 +321,7 @@ void __blk_run_queue(struct request_queue *q)
 	 * Only recurse once to avoid overrunning the stack, let the unplug
 	 * handling reinvoke the handler shortly if we already got there.
 	 */
-	if (!queue_flag_test_and_set(QUEUE_FLAG_REENTER, q)) {
+	if (!force_kblockd && !queue_flag_test_and_set(QUEUE_FLAG_REENTER, q)) {
 		q->request_fn(q);
 		queue_flag_clear(QUEUE_FLAG_REENTER, q);
 	} else
@@ -338,7 +342,7 @@ void blk_run_queue(struct request_queue *q)
 	unsigned long flags;
 
 	spin_lock_irqsave(q->queue_lock, flags);
-	__blk_run_queue(q);
+	__blk_run_queue(q, false);
 	spin_unlock_irqrestore(q->queue_lock, flags);
 }
 EXPORT_SYMBOL(blk_run_queue);
@@ -348,6 +352,11 @@ void blk_put_queue(struct request_queue *q)
 	kobject_put(&q->kobj);
 }
 
+/*
+ * Note: If a driver supplied the queue lock, it should not zap that lock
+ * unexpectedly as some queue cleanup components like elevator_exit() and
+ * blk_throtl_exit() need queue lock.
+ */
 void blk_cleanup_queue(struct request_queue *q)
 {
 	/*
@@ -366,6 +375,8 @@ void blk_cleanup_queue(struct request_queue *q)
 	if (q->elevator)
 		elevator_exit(q->elevator);
 
+	blk_throtl_exit(q);
+
 	blk_put_queue(q);
 }
 EXPORT_SYMBOL(blk_cleanup_queue);
@@ -439,6 +450,12 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
 	mutex_init(&q->sysfs_lock);
 	spin_lock_init(&q->__queue_lock);
 
+	/*
+	 * By default initialize queue_lock to internal lock and driver can
+	 * override it later if need be.
+	 */
+	q->queue_lock = &q->__queue_lock;
+
 	return q;
 }
 EXPORT_SYMBOL(blk_alloc_queue_node);
@@ -522,7 +539,10 @@ blk_init_allocated_queue_node(struct request_queue *q, request_fn_proc *rfn,
 	q->prep_rq_fn		= NULL;
 	q->unprep_rq_fn		= NULL;
 	q->queue_flags		= QUEUE_FLAG_DEFAULT;
-	q->queue_lock		= lock;
+
+	/* Override internal queue lock with supplied lock pointer */
+	if (lock)
+		q->queue_lock		= lock;
 
 	/*
 	 * This also sets hw/phys segments, boundary and size
@@ -971,7 +991,7 @@ void blk_insert_request(struct request_queue *q, struct request *rq,
 		blk_queue_end_tag(q, rq);
 
 	add_acct_request(q, rq, where);
-	__blk_run_queue(q);
+	__blk_run_queue(q, false);
 	spin_unlock_irqrestore(q->queue_lock, flags);
 }
 EXPORT_SYMBOL(blk_insert_request);
@@ -1307,7 +1327,7 @@ get_rq:
 	} else {
 		spin_lock_irq(q->queue_lock);
 		add_acct_request(q, req, where);
-		__blk_run_queue(q);
+		__blk_run_queue(q, false);
 out_unlock:
 		spin_unlock_irq(q->queue_lock);
 	}
@@ -2654,7 +2674,7 @@ static void flush_plug_list(struct blk_plug *plug)
 		BUG_ON(!rq->q);
 		if (rq->q != q) {
 			if (q) {
-				__blk_run_queue(q);
+				__blk_run_queue(q, false);
 				spin_unlock(q->queue_lock);
 			}
 			q = rq->q;
@@ -2669,7 +2689,7 @@ static void flush_plug_list(struct blk_plug *plug)
 	}
 
 	if (q) {
-		__blk_run_queue(q);
+		__blk_run_queue(q, false);
 		spin_unlock(q->queue_lock);
 	}