staging: hv: convert channel_mgmt.c to not call osd_schedule_callback

The additional abstraction is unneeded.

The three calls are assumed to not be pending simultaneously:
- vmbus_onoffer queues work exactly once when a new channel is
created, the channel is not attached to lists until the work
is executed
- vmbus_onoffer_rescind is received only when the channel is
active it is enough to process the work once
- free_channel is called exactly once when the channel is getting
destroyed; I assumed that vmbus_process_rescind_offer cannot be
pending while free_channel is called

Reviewed-By: Hank Janssen <[e-mail]>
Cc: Haiyang Zhang <[e-mail]>
Signed-off-by: Timo Teräs <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/hv/channel_mgmt.c

···
 /*
  * release_hannel - Release the vmbus channel object itself
  */
-static inline void release_channel(void *context)
+static void release_channel(struct work_struct *work)
 {
-	struct vmbus_channel *channel = context;
+	struct vmbus_channel *channel = container_of(work,
+						     struct vmbus_channel,
+						     work);
 
 	DPRINT_DBG(VMBUS, "releasing channel (%p)", channel);
 	destroy_workqueue(channel->controlwq);
···
 	 * workqueue/thread context
 	 * ie we can't destroy ourselves.
 	 */
-	osd_schedule_callback(gVmbusConnection.WorkQueue, release_channel,
-			      channel);
+	INIT_WORK(&channel->work, release_channel);
+	queue_work(gVmbusConnection.WorkQueue, &channel->work);
 }
 
 
···
 	spin_unlock_irqrestore(&gVmbusConnection.channel_lock, flags);
 }
 
+/*
+ * vmbus_process_rescind_offer -
+ * Rescind the offer by initiating a device removal
+ */
+static void vmbus_process_rescind_offer(struct work_struct *work)
+{
+	struct vmbus_channel *channel = container_of(work,
+						     struct vmbus_channel,
+						     work);
+
+	vmbus_child_device_unregister(channel->device_obj);
+}
 
 /*
  * vmbus_process_offer - Process the offer by creating a channel/device
  * associated with this offer
  */
-static void vmbus_process_offer(void *context)
+static void vmbus_process_offer(struct work_struct *work)
 {
-	struct vmbus_channel *newchannel = context;
+	struct vmbus_channel *newchannel = container_of(work,
+							struct vmbus_channel,
+							work);
 	struct vmbus_channel *channel;
 	bool fnew = true;
 	int ret;
 	int cnt;
 	unsigned long flags;
+
+	/* The next possible work is rescind handling */
+	INIT_WORK(&newchannel->work, vmbus_process_rescind_offer);
 
 	/* Make sure this is a new offer */
 	spin_lock_irqsave(&gVmbusConnection.channel_lock, flags);
···
 }
 
 /*
- * vmbus_process_rescind_offer -
- * Rescind the offer by initiating a device removal
- */
-static void vmbus_process_rescind_offer(void *context)
-{
-	struct vmbus_channel *channel = context;
-
-	vmbus_child_device_unregister(channel->device_obj);
-}
-
-/*
  * vmbus_onoffer - Handler for channel offers from vmbus in parent partition.
  *
  * We ignore all offers except network and storage offers. For each network and
···
 	newchannel->monitor_bit = (u8)offer->monitorid % 32;
 
 	/* TODO: Make sure the offer comes from our parent partition */
-	osd_schedule_callback(newchannel->controlwq, vmbus_process_offer,
-			      newchannel);
+	INIT_WORK(&newchannel->work, vmbus_process_offer);
+	queue_work(newchannel->controlwq, &newchannel->work);
 }
 
 /*
···
 		return;
 	}
 
-	osd_schedule_callback(channel->controlwq,
-			      vmbus_process_rescind_offer,
-			      channel);
+	/* work is initialized for vmbus_process_rescind_offer() from
+	 * vmbus_process_offer() where the channel got created */
+	queue_work(channel->controlwq, &channel->work);
 }
 
 /*

drivers/staging/hv/channel_mgmt.h

···
 	struct hv_device *device_obj;
 
 	struct timer_list poll_timer; /* SA-111 workaround */
+	struct work_struct work;
 
 	enum vmbus_channel_state state;