cxgb3: Rework t3_l2t_get to take a dst_entry instead of a neighbour.

This way we consolidate the RCU locking down into the place where it
actually matters, and also we can make the code handle
dst_get_neighbour_noref() returning NULL properly.

Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 22 insertions, 9 deletions

diff --git a/drivers/net/ethernet/chelsio/cxgb3/cxgb3_offload.c b/drivers/net/ethernet/chelsio/cxgb3/cxgb3_offload.c
index 6ed9f87db8ea..596cfe32d79e 100644
--- a/drivers/net/ethernet/chelsio/cxgb3/cxgb3_offload.c
+++ b/drivers/net/ethernet/chelsio/cxgb3/cxgb3_offload.c
@@ -1132,7 +1132,7 @@ static void cxgb_redirect(struct dst_entry *old, struct dst_entry *new)
         }
 
         /* Add new L2T entry */
-        e = t3_l2t_get(tdev, dst_get_neighbour_noref(new), newdev);
+        e = t3_l2t_get(tdev, new, newdev);
         if (!e) {
                 printk(KERN_ERR "%s: couldn't allocate new l2t entry!\n",
                        __func__);
diff --git a/drivers/net/ethernet/chelsio/cxgb3/l2t.c b/drivers/net/ethernet/chelsio/cxgb3/l2t.c
index 70fec8b1140f..3fa3c8833ed7 100644
--- a/drivers/net/ethernet/chelsio/cxgb3/l2t.c
+++ b/drivers/net/ethernet/chelsio/cxgb3/l2t.c
@@ -298,18 +298,31 @@ static inline void reuse_entry(struct l2t_entry *e, struct neighbour *neigh)
         spin_unlock(&e->lock);
 }
 
-struct l2t_entry *t3_l2t_get(struct t3cdev *cdev, struct neighbour *neigh,
+struct l2t_entry *t3_l2t_get(struct t3cdev *cdev, struct dst_entry *dst,
                              struct net_device *dev)
 {
         struct l2t_entry *e = NULL;
+        struct neighbour *neigh;
+        struct port_info *p;
         struct l2t_data *d;
         int hash;
-        u32 addr = *(u32 *) neigh->primary_key;
-        int ifidx = neigh->dev->ifindex;
-        struct port_info *p = netdev_priv(dev);
-        int smt_idx = p->port_id;
+        u32 addr;
+        int ifidx;
+        int smt_idx;
 
         rcu_read_lock();
+        neigh = dst_get_neighbour_noref(dst);
+        if (!neigh)
+                goto done_rcu;
+
+        addr = *(u32 *) neigh->primary_key;
+        ifidx = neigh->dev->ifindex;
+
+        if (!dev)
+                dev = neigh->dev;
+        p = netdev_priv(dev);
+        smt_idx = p->port_id;
+
         d = L2DATA(cdev);
         if (!d)
                 goto done_rcu;
@@ -323,7 +336,7 @@ struct l2t_entry *t3_l2t_get(struct t3cdev *cdev, struct neighbour *neigh,
                         l2t_hold(d, e);
                         if (atomic_read(&e->refcnt) == 1)
                                 reuse_entry(e, neigh);
-                        goto done;
+                        goto done_unlock;
                 }
 
         /* Need to allocate a new entry */
@@ -344,7 +357,7 @@ struct l2t_entry *t3_l2t_get(struct t3cdev *cdev, struct neighbour *neigh,
                         e->vlan = VLAN_NONE;
                 spin_unlock(&e->lock);
         }
-done:
+done_unlock:
         write_unlock_bh(&d->lock);
 done_rcu:
         rcu_read_unlock();
diff --git a/drivers/net/ethernet/chelsio/cxgb3/l2t.h b/drivers/net/ethernet/chelsio/cxgb3/l2t.h
index c5f54796e2cb..c4e864369751 100644
--- a/drivers/net/ethernet/chelsio/cxgb3/l2t.h
+++ b/drivers/net/ethernet/chelsio/cxgb3/l2t.h
@@ -109,7 +109,7 @@ static inline void set_arp_failure_handler(struct sk_buff *skb,
 
 void t3_l2e_free(struct l2t_data *d, struct l2t_entry *e);
 void t3_l2t_update(struct t3cdev *dev, struct neighbour *neigh);
-struct l2t_entry *t3_l2t_get(struct t3cdev *cdev, struct neighbour *neigh,
+struct l2t_entry *t3_l2t_get(struct t3cdev *cdev, struct dst_entry *dst,
                              struct net_device *dev);
 int t3_l2t_send_slow(struct t3cdev *dev, struct sk_buff *skb,
                      struct l2t_entry *e);