[NET]: Convert hh_lock to seqlock.

The hard header cache is in the main output path, so using
seqlock instead of reader/writer lock should reduce overhead.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 13 deletions

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index e9212c7ff5cf..7b7bd44fbf47 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -72,20 +72,11 @@ static __inline__ void ipv6_select_ident(struct sk_buff *skb, struct frag_hdr *f
 
 static inline int ip6_output_finish(struct sk_buff *skb)
 {
-
         struct dst_entry *dst = skb->dst;
-        struct hh_cache *hh = dst->hh;
-
-        if (hh) {
-                int hh_alen;
-
-                read_lock_bh(&hh->hh_lock);
-                hh_alen = HH_DATA_ALIGN(hh->hh_len);
-                memcpy(skb->data - hh_alen, hh->hh_data, hh_alen);
-                read_unlock_bh(&hh->hh_lock);
-                skb_push(skb, hh->hh_len);
-                return hh->hh_output(skb);
-        } else if (dst->neighbour)
+
+        if (dst->hh)
+                return neigh_hh_output(dst->hh, skb);
+        else if (dst->neighbour)
                 return dst->neighbour->output(skb);
 
         IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);