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| author |   Eric Dumazet <eric.dumazet@gmail.com> | 2010-10-07 10:44:07 +0000 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2010-10-11 12:54:04 -0700 |
| commit | 0ed8ddf4045fcfcac36bad753dc4046118c603ec (patch) | |
| tree | cf1d9eb14668c4d2257b3519ed7deec8c5cb396d /net/ipv4/arp.c | |
| parent | Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 (diff) | |
| download | linux-dev-0ed8ddf4045fcfcac36bad753dc4046118c603ec.tar.xz linux-dev-0ed8ddf4045fcfcac36bad753dc4046118c603ec.zip | |
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>
Diffstat (limited to 'net/ipv4/arp.c')
| -rw-r--r-- | net/ipv4/arp.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c index f35309578170..d8e540c5b071 100644 --- a/net/ipv4/arp.c +++ b/net/ipv4/arp.c @@ -502,10 +502,8 @@ int arp_find(unsigned char *haddr, struct sk_buff *skb) if (n) { n->used = jiffies; - if (n->nud_state&NUD_VALID || neigh_event_send(n, skb) == 0) { - read_lock_bh(&n->lock); - memcpy(haddr, n->ha, dev->addr_len); - read_unlock_bh(&n->lock); + if (n->nud_state & NUD_VALID || neigh_event_send(n, skb) == 0) { + neigh_ha_snapshot(haddr, n, dev); neigh_release(n); return 0; } |