[PATCH ipsec-next] xfrm: check for xdo_dev_state_free

[Shannon Nelson <shannon.nelson@oracle.com>]

The current XFRM code assumes that we've implemented the
xdo_dev_state_free() callback, even if it is meaningless to the driver.
This patch adds a check for it before calling, as done in other APIs,
and is done for the xdo_state_offload_ok() callback.

Also, we add a check for the required add and delete functions up front
at registration time to be sure both are defined, and complain if not.

Signed-off-by: Shannon Nelson <shannon.nelson@oracle.com>
---
 include/net/xfrm.h     |  3 ++-
 net/xfrm/xfrm_device.c | 18 ++++++++++++++----
 2 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index e015e16..dfabd04 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -1891,7 +1891,8 @@ static inline void xfrm_dev_state_free(struct xfrm_state *x)
 	 struct net_device *dev = xso->dev;
 
 	if (dev && dev->xfrmdev_ops) {
-		dev->xfrmdev_ops->xdo_dev_state_free(x);
+		if (dev->xfrmdev_ops->xdo_dev_state_free)
+			dev->xfrmdev_ops->xdo_dev_state_free(x);
 		xso->dev = NULL;
 		dev_put(dev);
 	}
diff --git a/net/xfrm/xfrm_device.c b/net/xfrm/xfrm_device.c
index 30e5746..0df1cc2 100644
--- a/net/xfrm/xfrm_device.c
+++ b/net/xfrm/xfrm_device.c
@@ -144,11 +144,21 @@ EXPORT_SYMBOL_GPL(xfrm_dev_offload_ok);
 
 static int xfrm_dev_register(struct net_device *dev)
 {
-	if ((dev->features & NETIF_F_HW_ESP) && !dev->xfrmdev_ops)
-		return NOTIFY_BAD;
-	if ((dev->features & NETIF_F_HW_ESP_TX_CSUM) &&
-	    !(dev->features & NETIF_F_HW_ESP))
+	if (!(dev->features & NETIF_F_HW_ESP)) {
+		if (dev->features & NETIF_F_HW_ESP_TX_CSUM) {
+			netdev_err(dev, "NETIF_F_HW_ESP_TX_CSUM without NETIF_F_HW_ESP\n");
+			return NOTIFY_BAD;
+		} else {
+			return NOTIFY_DONE;
+		}
+	}
+
+	if (!(dev->xfrmdev_ops &&
+	      dev->xfrmdev_ops->xdo_dev_state_add &&
+	      dev->xfrmdev_ops->xdo_dev_state_delete)) {
+		netdev_err(dev, "add or delete function missing from xfrmdev_ops\n");
 		return NOTIFY_BAD;
+	}
 
 	return NOTIFY_DONE;
 }
-- 
2.7.4