From: Jakub Kicinski <kuba@kernel.org>
Date: Tue, 8 Apr 2025 19:59:51 +0000 (-0700)
Subject: netdev: don't hold rtnl_lock over nl queue info get when possible
X-Git-Tag: v6.16-rc1~132^2~353^2~4
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d02e3b388221562cc7acabe700e3d3a29e51ad1d;p=thirdparty%2Flinux.git

netdev: don't hold rtnl_lock over nl queue info get when possible

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.

Reviewed-by: Joe Damato <jdamato@fastly.com>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Link: https://patch.msgid.link/20250408195956.412733-5-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---

diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
index 5d7af50fe7027..7ef9b01919364 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;
 }