neigh: Protect neigh->ha[] with a seqlock
Add a seqlock in struct neighbour to protect neigh->ha[], and avoid
dirtying neighbour in stress situation (many different flows / dsts)
Dirtying takes place because of read_lock(&n->lock) and n->used writes.
Switching to a seqlock, and writing n->used only on jiffies changes
permits less dirtying.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_teql.c b/net/sched/sch_teql.c
index feaabc1..401af95 100644
--- a/net/sched/sch_teql.c
+++ b/net/sched/sch_teql.c
@@ -241,11 +241,11 @@
}
if (neigh_event_send(n, skb_res) == 0) {
int err;
+ char haddr[MAX_ADDR_LEN];
- read_lock(&n->lock);
- err = dev_hard_header(skb, dev, ntohs(skb->protocol),
- n->ha, NULL, skb->len);
- read_unlock(&n->lock);
+ neigh_ha_snapshot(haddr, n, dev);
+ err = dev_hard_header(skb, dev, ntohs(skb->protocol), haddr,
+ NULL, skb->len);
if (err < 0) {
neigh_release(n);