An AoE session holds a persistent reference to a net device.

src/include/gpxe/aoe.h

 
 	/** Network device */
 	struct net_device *netdev;
+	/** Reference to network device */
+	struct reference netdev_ref;
+
 	/** Major number */
 	uint16_t major;
 	/** Minor number */

src/net/aoe.c

 	unsigned int count;
 	unsigned int data_out_len;
 
+	/* Fail immediately if we have no netdev to send on */
+	if ( ! aoe->netdev ) {
+		aoe_done ( aoe, -ENETUNREACH );
+		return -ENETUNREACH;
+	}
+
 	/* Calculate count and data_out_len for this subcommand */
 	count = command->cb.count.native;
 	if ( count > AOE_MAX_COUNT )
 	.rx = aoe_rx,
 };
 
+/**
+ * Forget reference to net_device
+ *
+ * @v ref		Persistent reference
+ */
+static void aoe_forget_netdev ( struct reference *ref ) {
+	struct aoe_session *aoe
+		= container_of ( ref, struct aoe_session, netdev_ref );
+
+	aoe->netdev = NULL;
+	ref_del ( &aoe->netdev_ref );
+}
+
 /**
  * Open AoE session
  *
 		 sizeof ( aoe->target ) );
 	aoe->tag = AOE_TAG_MAGIC;
 	aoe->timer.expired = aoe_timer_expired;
+	aoe->netdev_ref.forget = aoe_forget_netdev;
+	ref_add ( &aoe->netdev_ref, &aoe->netdev->references );
 	list_add ( &aoe->list, &aoe_sessions );
 }
 
  * @v aoe		AoE session
  */
 void aoe_close ( struct aoe_session *aoe ) {
+	if ( aoe->netdev )
+		ref_del ( &aoe->netdev_ref );
 	list_del ( &aoe->list );
 }