From 6747a5d4990b8c8d7392f7a06b7a4bb5f4ada80e Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 3 May 2024 19:20:56 +0000 Subject: rtnetlink: do not depend on RTNL for many attributes Following device fields can be read locklessly in rtnl_fill_ifinfo() : type, ifindex, operstate, link_mode, mtu, min_mtu, max_mtu, group, promiscuity, allmulti, num_tx_queues, gso_max_segs, gso_max_size, gro_max_size, gso_ipv4_max_size, gro_ipv4_max_size, tso_max_size, tso_max_segs, num_rx_queues. Signed-off-by: Eric Dumazet Signed-off-by: Paolo Abeni --- net/core/rtnetlink.c | 51 +++++++++++++++++++++++++++++++-------------------- 1 file changed, 31 insertions(+), 20 deletions(-) diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 7e156f535bd8..16b5f9c68bbf 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -1603,7 +1603,8 @@ static int put_master_ifindex(struct sk_buff *skb, struct net_device *dev) upper_dev = netdev_master_upper_dev_get_rcu(dev); if (upper_dev) - ret = nla_put_u32(skb, IFLA_MASTER, upper_dev->ifindex); + ret = nla_put_u32(skb, IFLA_MASTER, + READ_ONCE(upper_dev->ifindex)); rcu_read_unlock(); return ret; @@ -1825,8 +1826,8 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, ifm = nlmsg_data(nlh); ifm->ifi_family = AF_UNSPEC; ifm->__ifi_pad = 0; - ifm->ifi_type = dev->type; - ifm->ifi_index = dev->ifindex; + ifm->ifi_type = READ_ONCE(dev->type); + ifm->ifi_index = READ_ONCE(dev->ifindex); ifm->ifi_flags = dev_get_flags(dev); ifm->ifi_change = change; @@ -1839,24 +1840,34 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, if (nla_put_u32(skb, IFLA_TXQLEN, READ_ONCE(dev->tx_queue_len)) || nla_put_u8(skb, IFLA_OPERSTATE, - netif_running(dev) ? dev->operstate : IF_OPER_DOWN) || - nla_put_u8(skb, IFLA_LINKMODE, dev->link_mode) || - nla_put_u32(skb, IFLA_MTU, dev->mtu) || - nla_put_u32(skb, IFLA_MIN_MTU, dev->min_mtu) || - nla_put_u32(skb, IFLA_MAX_MTU, dev->max_mtu) || - nla_put_u32(skb, IFLA_GROUP, dev->group) || - nla_put_u32(skb, IFLA_PROMISCUITY, dev->promiscuity) || - nla_put_u32(skb, IFLA_ALLMULTI, dev->allmulti) || - nla_put_u32(skb, IFLA_NUM_TX_QUEUES, dev->num_tx_queues) || - nla_put_u32(skb, IFLA_GSO_MAX_SEGS, dev->gso_max_segs) || - nla_put_u32(skb, IFLA_GSO_MAX_SIZE, dev->gso_max_size) || - nla_put_u32(skb, IFLA_GRO_MAX_SIZE, dev->gro_max_size) || - nla_put_u32(skb, IFLA_GSO_IPV4_MAX_SIZE, dev->gso_ipv4_max_size) || - nla_put_u32(skb, IFLA_GRO_IPV4_MAX_SIZE, dev->gro_ipv4_max_size) || - nla_put_u32(skb, IFLA_TSO_MAX_SIZE, dev->tso_max_size) || - nla_put_u32(skb, IFLA_TSO_MAX_SEGS, dev->tso_max_segs) || + netif_running(dev) ? READ_ONCE(dev->operstate) : + IF_OPER_DOWN) || + nla_put_u8(skb, IFLA_LINKMODE, READ_ONCE(dev->link_mode)) || + nla_put_u32(skb, IFLA_MTU, READ_ONCE(dev->mtu)) || + nla_put_u32(skb, IFLA_MIN_MTU, READ_ONCE(dev->min_mtu)) || + nla_put_u32(skb, IFLA_MAX_MTU, READ_ONCE(dev->max_mtu)) || + nla_put_u32(skb, IFLA_GROUP, READ_ONCE(dev->group)) || + nla_put_u32(skb, IFLA_PROMISCUITY, READ_ONCE(dev->promiscuity)) || + nla_put_u32(skb, IFLA_ALLMULTI, READ_ONCE(dev->allmulti)) || + nla_put_u32(skb, IFLA_NUM_TX_QUEUES, + READ_ONCE(dev->num_tx_queues)) || + nla_put_u32(skb, IFLA_GSO_MAX_SEGS, + READ_ONCE(dev->gso_max_segs)) || + nla_put_u32(skb, IFLA_GSO_MAX_SIZE, + READ_ONCE(dev->gso_max_size)) || + nla_put_u32(skb, IFLA_GRO_MAX_SIZE, + READ_ONCE(dev->gro_max_size)) || + nla_put_u32(skb, IFLA_GSO_IPV4_MAX_SIZE, + READ_ONCE(dev->gso_ipv4_max_size)) || + nla_put_u32(skb, IFLA_GRO_IPV4_MAX_SIZE, + READ_ONCE(dev->gro_ipv4_max_size)) || + nla_put_u32(skb, IFLA_TSO_MAX_SIZE, + READ_ONCE(dev->tso_max_size)) || + nla_put_u32(skb, IFLA_TSO_MAX_SEGS, + READ_ONCE(dev->tso_max_segs)) || #ifdef CONFIG_RPS - nla_put_u32(skb, IFLA_NUM_RX_QUEUES, dev->num_rx_queues) || + nla_put_u32(skb, IFLA_NUM_RX_QUEUES, + READ_ONCE(dev->num_rx_queues)) || #endif put_master_ifindex(skb, dev) || nla_put_u8(skb, IFLA_CARRIER, netif_carrier_ok(dev)) || -- cgit v1.2.3