packet: less dev_put() calls
- packet_sendmsg_spkt() can use dev_get_by_name_rcu() to avoid touching device refcount.
- packet_getname_spkt() & packet_getname() can use dev_get_by_index_rcu() to
avoid touching device refcount too.
tpacket_snd() & packet_snd() can not use RCU yet because they can sleep when
allocating skb.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 95ef64e..91d246d 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -437,7 +437,8 @@
*/
saddr->spkt_device[13] = 0;
- dev = dev_get_by_name(sock_net(sk), saddr->spkt_device);
+ rcu_read_lock();
+ dev = dev_get_by_name_rcu(sock_net(sk), saddr->spkt_device);
err = -ENODEV;
if (dev == NULL)
goto out_unlock;
@@ -500,14 +501,13 @@
*/
dev_queue_xmit(skb);
- dev_put(dev);
+ rcu_read_unlock();
return len;
out_free:
kfree_skb(skb);
out_unlock:
- if (dev)
- dev_put(dev);
+ rcu_read_unlock();
return err;
}
@@ -1518,12 +1518,13 @@
return -EOPNOTSUPP;
uaddr->sa_family = AF_PACKET;
- dev = dev_get_by_index(sock_net(sk), pkt_sk(sk)->ifindex);
- if (dev) {
+ rcu_read_lock();
+ dev = dev_get_by_index_rcu(sock_net(sk), pkt_sk(sk)->ifindex);
+ if (dev)
strlcpy(uaddr->sa_data, dev->name, 15);
- dev_put(dev);
- } else
+ else
memset(uaddr->sa_data, 0, 14);
+ rcu_read_unlock();
*uaddr_len = sizeof(*uaddr);
return 0;
@@ -1543,16 +1544,17 @@
sll->sll_family = AF_PACKET;
sll->sll_ifindex = po->ifindex;
sll->sll_protocol = po->num;
- dev = dev_get_by_index(sock_net(sk), po->ifindex);
+ rcu_read_lock();
+ dev = dev_get_by_index_rcu(sock_net(sk), po->ifindex);
if (dev) {
sll->sll_hatype = dev->type;
sll->sll_halen = dev->addr_len;
memcpy(sll->sll_addr, dev->dev_addr, dev->addr_len);
- dev_put(dev);
} else {
sll->sll_hatype = 0; /* Bad: we have no ARPHRD_UNSPEC */
sll->sll_halen = 0;
}
+ rcu_read_unlock();
*uaddr_len = offsetof(struct sockaddr_ll, sll_addr) + sll->sll_halen;
return 0;