From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: [PATCH net-next-2.6] packet: less dev_put() calls Date: Mon, 02 Nov 2009 10:43:32 +0100 Message-ID: <4AEEA9C4.6040305@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Linux Netdev List To: "David S. Miller" Return-path: Received: from gw1.cosmosbay.com ([212.99.114.194]:44218 "EHLO gw1.cosmosbay.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754105AbZKBJna (ORCPT ); Mon, 2 Nov 2009 04:43:30 -0500 Sender: netdev-owner@vger.kernel.org List-ID: - 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 --- net/packet/af_packet.c | 22 ++++++++++++---------- 1 files changed, 12 insertions(+), 10 deletions(-) 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 @@ static int packet_sendmsg_spkt(struct kiocb *iocb, struct socket *sock, */ 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 @@ static int packet_sendmsg_spkt(struct kiocb *iocb, struct socket *sock, */ 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 @@ static int packet_getname_spkt(struct socket *sock, struct sockaddr *uaddr, 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 @@ static int packet_getname(struct socket *sock, struct sockaddr *uaddr, 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;