hv: remove the per-channel workqueue

It's not necessary any longer, since we can safely run the blocking
message handlers in vmbus_connection.work_queue now.

Signed-off-by: Dexuan Cui <decui@microsoft.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hv/channel_mgmt.c

@@ -147,43 +147,15 @@ static struct vmbus_channel *alloc_channel(void)
 	INIT_LIST_HEAD(&channel->sc_list);
 	INIT_LIST_HEAD(&channel->percpu_list);
 
-	channel->controlwq = alloc_workqueue("hv_vmbus_ctl/%d", WQ_MEM_RECLAIM,
-					     1, channel->id);
-	if (!channel->controlwq) {
-		kfree(channel);
-		return NULL;
-	}
-
 	return channel;
 }
 
-/*
- * release_hannel - Release the vmbus channel object itself
- */
-static void release_channel(struct work_struct *work)
-{
-	struct vmbus_channel *channel = container_of(work,
-						     struct vmbus_channel,
-						     work);
-
-	destroy_workqueue(channel->controlwq);
-
-	kfree(channel);
-}
-
 /*
  * free_channel - Release the resources used by the vmbus channel object
  */
 static void free_channel(struct vmbus_channel *channel)
 {
-
-	/*
-	 * We have to release the channel's workqueue/thread in the vmbus's
-	 * workqueue/thread context
-	 * ie we can't destroy ourselves.
-	 */
-	INIT_WORK(&channel->work, release_channel);
-	queue_work(vmbus_connection.work_queue, &channel->work);
+	kfree(channel);
 }
 
 static void percpu_channel_enq(void *arg)

include/linux/hyperv.h

@@ -653,8 +653,6 @@ struct vmbus_channel {
 
 	struct hv_device *device_obj;
 
-	struct work_struct work;
-
 	enum vmbus_channel_state state;
 
 	struct vmbus_channel_offer_channel offermsg;
@@ -675,7 +673,6 @@ struct vmbus_channel {
 	struct hv_ring_buffer_info outbound;	/* send to parent */
 	struct hv_ring_buffer_info inbound;	/* receive from parent */
 	spinlock_t inbound_lock;
-	struct workqueue_struct *controlwq;
 
 	struct vmbus_close_msg close_msg;