Staging: hv: Introduce a function to map a generic driver pointer to a pointer to struct netvsc_driver

In preparation for getting rid of the priv element from struct hv_driver,
introduce a function to map a generic driver pointer to a pointer to
struct netvsc_driver.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Abhishek Kane <v-abkane@microsoft.com>
Signed-off-by: Hank Janssen <hjanssen@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/hv/netvsc_api.h

@@ -26,6 +26,7 @@
 #define _NETVSC_API_H_
 
 #include "vmbus_api.h"
+#include "vmbus.h"
 
 /* Fwd declaration */
 struct hv_netvsc_packet;
@@ -103,6 +104,13 @@ struct netvsc_driver {
 	void *ctx;
 };
 
+static inline
+struct netvsc_driver *drv_to_netvscdrv(struct device_driver *d)
+{
+	struct hv_driver *hvdrv = drv_to_hv_drv(d);
+	return container_of(hvdrv, struct netvsc_driver, base);
+}
+
 struct netvsc_device_info {
 	unsigned char mac_adr[6];
 	bool link_state;	/* 0 - link up, 1 - link down */