[PATCHv2 net-next 1/3] bonding: add common function to check ipsec device

[Hangbin Liu <liuhangbin@gmail.com>]

This patch adds a common function to check the status of IPSec devices.
This function will be useful for future implementations, such as IPSec ESN
and state offload callbacks.

Suggested-by: Nikolay Aleksandrov <razor@blackwall.org>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
---
 drivers/net/bonding/bond_main.c | 43 +++++++++++++++++++++++----------
 1 file changed, 30 insertions(+), 13 deletions(-)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index f9633a6f8571..250a2717b4e9 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -418,6 +418,34 @@ static int bond_vlan_rx_kill_vid(struct net_device *bond_dev,
 /*---------------------------------- XFRM -----------------------------------*/
 
 #ifdef CONFIG_XFRM_OFFLOAD
+/**
+ * bond_ipsec_dev - return the device for ipsec offload, or NULL if not exist
+ *                  caller must hold rcu_read_lock.
+ * @xs: pointer to transformer state struct
+ **/
+static struct net_device bond_ipsec_dev(struct xfrm_state *xs)
+{
+	struct net_device *bond_dev = xs->xso.dev;
+	struct net_device *real_dev;
+	struct bonding *bond;
+	struct slave *slave;
+
+	if (!bond_dev)
+		return NULL;
+
+	bond = netdev_priv(bond_dev);
+	slave = rcu_dereference(bond->curr_active_slave);
+	real_dev = slave ? slave->dev : NULL;
+
+	if ((BOND_MODE(bond) != BOND_MODE_ACTIVEBACKUP) ||
+	    !slave || !real_dev || !xs->xso.real_dev)
+		return NULL;
+
+	WARN_ON(xs->xso.real_dev != slave->dev);
+
+	return real_dev;
+}
+
 /**
  * bond_ipsec_add_sa - program device with a security association
  * @xs: pointer to transformer state struct
@@ -595,23 +623,12 @@ static void bond_ipsec_del_sa_all(struct bonding *bond)
  **/
 static bool bond_ipsec_offload_ok(struct sk_buff *skb, struct xfrm_state *xs)
 {
-	struct net_device *bond_dev = xs->xso.dev;
 	struct net_device *real_dev;
-	struct slave *curr_active;
-	struct bonding *bond;
 	int err;
 
-	bond = netdev_priv(bond_dev);
 	rcu_read_lock();
-	curr_active = rcu_dereference(bond->curr_active_slave);
-	real_dev = curr_active->dev;
-
-	if (BOND_MODE(bond) != BOND_MODE_ACTIVEBACKUP) {
-		err = false;
-		goto out;
-	}
-
-	if (!xs->xso.real_dev) {
+	real_dev = bond_ipsec_dev(xs);
+	if (!real_dev) {
 		err = false;
 		goto out;
 	}
-- 
2.45.0