Drivers: hv: avoid passing opaque pointer to vmbus_onmessage()

vmbus_onmessage() doesn't need the header of the message, it only
uses it to get to the payload, we can pass the pointer to the
payload directly.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20200406104154.45010-4-vkuznets@redhat.comSigned-off-by: Wei Liu <wei.liu@kernel.org>

drivers/hv/channel_mgmt.c

@@ -1363,13 +1363,8 @@ channel_message_table[CHANNELMSG_COUNT] = {
  *
  * This is invoked in the vmbus worker thread context.
  */
-void vmbus_onmessage(void *context)
+void vmbus_onmessage(struct vmbus_channel_message_header *hdr)
 {
-	struct hv_message *msg = context;
-	struct vmbus_channel_message_header *hdr;
-
-	hdr = (struct vmbus_channel_message_header *)msg->u.payload;
-
 	trace_vmbus_on_message(hdr);
 
 	/*

drivers/hv/vmbus_drv.c

@@ -1035,7 +1035,8 @@ static void vmbus_onmessage_work(struct work_struct *work)
 
 	ctx = container_of(work, struct onmessage_work_context,
 			   work);
-	vmbus_onmessage(&ctx->msg);
+	vmbus_onmessage((struct vmbus_channel_message_header *)
+			&ctx->msg.payload);
 	kfree(ctx);
 }
 

include/linux/hyperv.h

@@ -1017,7 +1017,7 @@ static inline void clear_low_latency_mode(struct vmbus_channel *c)
 	c->low_latency = false;
 }
 
-void vmbus_onmessage(void *context);
+void vmbus_onmessage(struct vmbus_channel_message_header *hdr);
 
 int vmbus_request_offers(void);