[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>
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index c57088f..631cec4 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -199,7 +199,7 @@
*/
u16 hh_len; /* length of header */
int (*hh_output)(struct sk_buff *skb);
- rwlock_t hh_lock;
+ seqlock_t hh_lock;
/* cached hardware header; allow for machine alignment needs. */
#define HH_DATA_MOD 16
diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index 2396703..3725b93 100644
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -309,6 +309,24 @@
return 0;
}
+static inline int neigh_hh_output(struct hh_cache *hh, struct sk_buff *skb)
+{
+ unsigned seq;
+ int hh_len;
+
+ do {
+ int hh_alen;
+
+ seq = read_seqbegin(&hh->hh_lock);
+ hh_len = hh->hh_len;
+ hh_alen = HH_DATA_ALIGN(hh_len);
+ memcpy(skb->data - hh_alen, hh->hh_data, hh_alen);
+ } while (read_seqretry(&hh->hh_lock, seq));
+
+ skb_push(skb, hh_len);
+ return hh->hh_output(skb);
+}
+
static inline struct neighbour *
__neigh_lookup(struct neigh_table *tbl, const void *pkey, struct net_device *dev, int creat)
{