hyperv: Add support for physically discontinuous receive buffer

This will allow us to use bigger receive buffer, and prevent allocation failure
due to fragmented memory.

Signed-off-by: Haiyang Zhang <[e-mail]>
Reviewed-by: K. Y. Srinivasan <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/hv/channel.c

···
 {
 	int i;
 	int pagecount;
-	unsigned long long pfn;
 	struct vmbus_channel_gpadl_header *gpadl_header;
 	struct vmbus_channel_gpadl_body *gpadl_body;
 	struct vmbus_channel_msginfo *msgheader;
···
 	int pfnsum, pfncount, pfnleft, pfncurr, pfnsize;
 
 	pagecount = size >> PAGE_SHIFT;
-	pfn = virt_to_phys(kbuffer) >> PAGE_SHIFT;
 
 	/* do we need a gpadl body msg */
 	pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
···
 		gpadl_header->range[0].byte_offset = 0;
 		gpadl_header->range[0].byte_count = size;
 		for (i = 0; i < pfncount; i++)
-			gpadl_header->range[0].pfn_array[i] = pfn+i;
+			gpadl_header->range[0].pfn_array[i] = slow_virt_to_phys(
+				kbuffer + PAGE_SIZE * i) >> PAGE_SHIFT;
 		*msginfo = msgheader;
 		*messagecount = 1;
 
···
 			 * so the hypervisor gurantees that this is ok.
 			 */
 			for (i = 0; i < pfncurr; i++)
-				gpadl_body->pfn[i] = pfn + pfnsum + i;
+				gpadl_body->pfn[i] = slow_virt_to_phys(
+					kbuffer + PAGE_SIZE * (pfnsum + i)) >>
+					PAGE_SHIFT;
 
 			/* add to msg header */
 			list_add_tail(&msgbody->msglistentry,
···
 		gpadl_header->range[0].byte_offset = 0;
 		gpadl_header->range[0].byte_count = size;
 		for (i = 0; i < pagecount; i++)
-			gpadl_header->range[0].pfn_array[i] = pfn+i;
+			gpadl_header->range[0].pfn_array[i] = slow_virt_to_phys(
+				kbuffer + PAGE_SIZE * i) >> PAGE_SHIFT;
 
 		*msginfo = msgheader;
 		*messagecount = 1;
···
  * vmbus_establish_gpadl - Estabish a GPADL for the specified buffer
  *
  * @channel: a channel
- * @kbuffer: from kmalloc
+ * @kbuffer: from kmalloc or vmalloc
  * @size: page-size multiple
  * @gpadl_handle: some funky thing
  */

drivers/net/hyperv/hyperv_net.h

···
 
 #define NETVSC_MTU 65536
 
-#define NETVSC_RECEIVE_BUFFER_SIZE		(1024*1024*2)	/* 2MB */
+#define NETVSC_RECEIVE_BUFFER_SIZE		(1024*1024*16)	/* 16MB */
 
 #define NETVSC_RECEIVE_BUFFER_ID		0xcafe
 

drivers/net/hyperv/netvsc.c

···
 
 	if (net_device->recv_buf) {
 		/* Free up the receive buffer */
-		free_pages((unsigned long)net_device->recv_buf,
-			get_order(net_device->recv_buf_size));
+		vfree(net_device->recv_buf);
 		net_device->recv_buf = NULL;
 	}
 
···
 		return -ENODEV;
 	ndev = net_device->ndev;
 
-	net_device->recv_buf =
-		(void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO,
-				get_order(net_device->recv_buf_size));
+	net_device->recv_buf = vzalloc(net_device->recv_buf_size);
 	if (!net_device->recv_buf) {
 		netdev_err(ndev, "unable to allocate receive "
 			"buffer of size %d\n", net_device->recv_buf_size);