net: Do delayed neigh confirmation.

When a dst_confirm() happens, mark the confirmation as pending in the
dst.  Then on the next packet out, when we have the neigh in-hand, do
the update.

This removes the dependency in dst_confirm() of dst's having an
attached neigh.

While we're here, remove the explicit 'dst' NULL check, all except 2
or 3 call sites ensure it's not NULL.  So just fix those cases up.

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

1 files changed, 21 insertions, 8 deletions

diff --git a/include/net/dst.h b/include/net/dst.h
index f0bf3b8d591..84e7a3ff968 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -51,7 +51,7 @@ struct dst_entry {
         int                     (*input)(struct sk_buff *);
         int                     (*output)(struct sk_buff *);
 
-        int                     flags;
+        unsigned short          flags;
 #define DST_HOST                0x0001
 #define DST_NOXFRM              0x0002
 #define DST_NOPOLICY            0x0004
@@ -62,6 +62,8 @@ struct dst_entry {
 #define DST_FAKE_RTABLE         0x0080
 #define DST_XFRM_TUNNEL         0x0100
 
+        unsigned short          pending_confirm;
+
         short                   error;
         short                   obsolete;
         unsigned short          header_len;     /* more space at head required */
@@ -371,7 +373,8 @@ static inline struct dst_entry *skb_dst_pop(struct sk_buff *skb)
 
 extern int dst_discard(struct sk_buff *skb);
 extern void *dst_alloc(struct dst_ops *ops, struct net_device *dev,
-                       int initial_ref, int initial_obsolete, int flags);
+                       int initial_ref, int initial_obsolete,
+                       unsigned short flags);
 extern void __dst_free(struct dst_entry *dst);
 extern struct dst_entry *dst_destroy(struct dst_entry *dst);
 
@@ -395,14 +398,24 @@ static inline void dst_rcu_free(struct rcu_head *head)
 
 static inline void dst_confirm(struct dst_entry *dst)
 {
-        if (dst) {
-                struct neighbour *n;
+        dst->pending_confirm = 1;
+}
 
-                rcu_read_lock();
-                n = dst_get_neighbour_noref(dst);
-                neigh_confirm(n);
-                rcu_read_unlock();
+static inline int dst_neigh_output(struct dst_entry *dst, struct neighbour *n,
+                                   struct sk_buff *skb)
+{
+        struct hh_cache *hh;
+
+        if (unlikely(dst->pending_confirm)) {
+                n->confirmed = jiffies;
+                dst->pending_confirm = 0;
         }
+
+        hh = &n->hh;
+        if ((n->nud_state & NUD_CONNECTED) && hh->hh_len)
+                return neigh_hh_output(hh, skb);
+        else
+                return n->output(n, skb);
 }
 
 static inline struct neighbour *dst_neigh_lookup(const struct dst_entry *dst, const void *daddr)