[PATCH net-next 4/8] netdev: don't hold rtnl_lock over nl queue info get when possible

Jakub Kicinski
2025-04-07T19:01:19Z

Netdev queue dump accesses: NAPI, memory providers, XSk pointers.
All three are "ops protected" now, switch to the op compat locking.
rtnl lock does not have to be taken for "ops locked" devices.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
net/core/netdev-genl.c | 18 +++++++-----------
1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
index 5d7af50fe702..7ef9b0191936 100644
--- a/net/core/netdev-genl.c
+++ b/net/core/netdev-genl.c
@@ -481,18 +481,15 @@ int netdev_nl_queue_get_doit(struct sk_buff *skb, struct genl_info *info)
if (!rsp)
return -ENOMEM;

- rtnl_lock();
-
- netdev = netdev_get_by_index_lock(genl_info_net(info), ifindex);
+ netdev = netdev_get_by_index_lock_ops_compat(genl_info_net(info),
+ ifindex);
if (netdev) {
err = netdev_nl_queue_fill(rsp, netdev, q_id, q_type, info);
- netdev_unlock(netdev);
+ netdev_unlock_ops_compat(netdev);
} else {
err = -ENODEV;
}

- rtnl_unlock();
-
if (err)
goto err_free_msg;

@@ -541,17 +538,17 @@ int netdev_nl_queue_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
if (info->attrs[NETDEV_A_QUEUE_IFINDEX])
ifindex = nla_get_u32(info->attrs[NETDEV_A_QUEUE_IFINDEX]);

- rtnl_lock();
if (ifindex) {
- netdev = netdev_get_by_index_lock(net, ifindex);
+ netdev = netdev_get_by_index_lock_ops_compat(net, ifindex);
if (netdev) {
err = netdev_nl_queue_dump_one(netdev, skb, info, ctx);
- netdev_unlock(netdev);
+ netdev_unlock_ops_compat(netdev);
} else {
err = -ENODEV;
}
} else {
- for_each_netdev_lock_scoped(net, netdev, ctx->ifindex) {
+ for_each_netdev_lock_ops_compat_scoped(net, netdev,
+ ctx->ifindex) {
err = netdev_nl_queue_dump_one(netdev, skb, info, ctx);
if (err < 0)
break;
@@ -559,7 +556,6 @@ int netdev_nl_queue_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
ctx->txq_idx = 0;
}
}
- rtnl_unlock();

return err;
}
--
2.49.0