Drivers: hv: vmbus: Suport an API to send pagebuffers with additional control

Implement an API for sending pagebuffers that gives more control to the client
in terms of setting the vmbus flags as well as deciding when to
notify the host. This will be useful for enabling batch processing.

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

include/linux/hyperv.h

@@ -874,6 +874,15 @@ extern int vmbus_sendpacket_pagebuffer(struct vmbus_channel *channel,
 					    u32 bufferlen,
 					    u64 requestid);
 
+extern int vmbus_sendpacket_pagebuffer_ctl(struct vmbus_channel *channel,
+					   struct hv_page_buffer pagebuffers[],
+					   u32 pagecount,
+					   void *buffer,
+					   u32 bufferlen,
+					   u64 requestid,
+					   u32 flags,
+					   bool kick_q);
+
 extern int vmbus_sendpacket_multipagebuffer(struct vmbus_channel *channel,
 					struct hv_multipage_buffer *mpb,
 					void *buffer,