netdevice: add the case if dev is NULL

commit b37a466 upstream.

Add the case if dev is NULL in dev_{put, hold}, so the caller doesn't
need to care whether dev is NULL or not.

Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Pavel Machek <pavel@denx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/linux/netdevice.h

@@ -3980,7 +3980,8 @@ void netdev_run_todo(void);
  */
 static inline void dev_put(struct net_device *dev)
 {
-	this_cpu_dec(*dev->pcpu_refcnt);
+	if (dev)
+		this_cpu_dec(*dev->pcpu_refcnt);
 }
 
 /**
@@ -3991,7 +3992,8 @@ static inline void dev_put(struct net_device *dev)
  */
 static inline void dev_hold(struct net_device *dev)
 {
-	this_cpu_inc(*dev->pcpu_refcnt);
+	if (dev)
+		this_cpu_inc(*dev->pcpu_refcnt);
 }
 
 /* Carrier loss detection, dial on demand. The functions netif_carrier_on