rtnetlink: do not depend on RTNL for IFLA_TXQLEN output

rtnl_fill_ifinfo() can read dev->tx_queue_len locklessly,
granted we add corresponding READ_ONCE()/WRITE_ONCE() annotations.

Add missing READ_ONCE(dev->tx_queue_len) in teql_enqueue()

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/net/core/dev.c b/net/core/dev.c
index d6b24749eb2e27ca87609e31b0434c6c09f0e8d8..882ce6375b2e6ba7dfaee5df4e933463aa100e5b 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -8959,7 +8959,7 @@ int dev_change_tx_queue_len(struct net_device *dev, unsigned long new_len)
                return -ERANGE;
 
        if (new_len != orig_len) {
-               dev->tx_queue_len = new_len;
+               WRITE_ONCE(dev->tx_queue_len, new_len);
                res = call_netdevice_notifiers(NETDEV_CHANGE_TX_QUEUE_LEN, dev);
                res = notifier_to_errno(res);
                if (res)
@@ -8973,7 +8973,7 @@ int dev_change_tx_queue_len(struct net_device *dev, unsigned long new_len)
 
 err_rollback:
        netdev_err(dev, "refused to change device tx_queue_len\n");
-       dev->tx_queue_len = orig_len;
+       WRITE_ONCE(dev->tx_queue_len, orig_len);
        return res;
 }
 

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index eb1a151c69107b84b57fb364c153bff6cfc10eb3..7e156f535bd8538c7e3946a8778b98a931e99815 100644 (file)
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1837,7 +1837,7 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb,
        if (nla_put_string(skb, IFLA_IFNAME, devname))
                goto nla_put_failure;
 
-       if (nla_put_u32(skb, IFLA_TXQLEN, dev->tx_queue_len) ||
+       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) ||

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 6292d6d73b720fef6766d08ed01d8b93a99f97b6..74afc210527d237cca3b48166be5918f802eb326 100644 (file)
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -1334,7 +1334,7 @@ static struct Qdisc *qdisc_create(struct net_device *dev,
         * before again attaching a qdisc.
         */
        if ((dev->priv_flags & IFF_NO_QUEUE) && (dev->tx_queue_len == 0)) {
-               dev->tx_queue_len = DEFAULT_TX_QUEUE_LEN;
+               WRITE_ONCE(dev->tx_queue_len, DEFAULT_TX_QUEUE_LEN);
                netdev_info(dev, "Caught tx_queue_len zero misconfig\n");
        }
 

diff --git a/net/sched/sch_teql.c b/net/sched/sch_teql.c
index 59304611dc0050e525de5f45b2a3b8628b684ff3..29850d0f073308290ac1a479bc98315034990663 100644 (file)
--- a/net/sched/sch_teql.c
+++ b/net/sched/sch_teql.c
@@ -78,7 +78,7 @@ teql_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free)
        struct net_device *dev = qdisc_dev(sch);
        struct teql_sched_data *q = qdisc_priv(sch);
 
-       if (q->q.qlen < dev->tx_queue_len) {
+       if (q->q.qlen < READ_ONCE(dev->tx_queue_len)) {
                __skb_queue_tail(&q->q, skb);
                return NET_XMIT_SUCCESS;
        }