netdev-genl: remove rtnl_lock protection from NAPI ops

NAPI lifetime, visibility and config are all fully under
netdev_lock protection now.

Reviewed-by: Joe Damato <jdamato@fastly.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250115035319.559603-12-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/core/netdev-genl.c

@@ -229,8 +229,6 @@ int netdev_nl_napi_get_doit(struct sk_buff *skb, struct genl_info *info)
 	if (!rsp)
 		return -ENOMEM;
 
-	rtnl_lock();
-
 	napi = netdev_napi_by_id_lock(genl_info_net(info), napi_id);
 	if (napi) {
 		err = netdev_nl_napi_fill_one(rsp, napi, info);
@@ -240,8 +238,6 @@ int netdev_nl_napi_get_doit(struct sk_buff *skb, struct genl_info *info)
 		err = -ENOENT;
 	}
 
-	rtnl_unlock();
-
 	if (err) {
 		goto err_free_msg;
 	} else if (!rsp->len) {
@@ -300,7 +296,6 @@ int netdev_nl_napi_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 	if (info->attrs[NETDEV_A_NAPI_IFINDEX])
 		ifindex = nla_get_u32(info->attrs[NETDEV_A_NAPI_IFINDEX]);
 
-	rtnl_lock();
 	if (ifindex) {
 		netdev = netdev_get_by_index_lock(net, ifindex);
 		if (netdev) {
@@ -317,7 +312,6 @@ int netdev_nl_napi_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
 			ctx->napi_id = 0;
 		}
 	}
-	rtnl_unlock();
 
 	return err;
 }
@@ -358,8 +352,6 @@ int netdev_nl_napi_set_doit(struct sk_buff *skb, struct genl_info *info)
 
 	napi_id = nla_get_u32(info->attrs[NETDEV_A_NAPI_ID]);
 
-	rtnl_lock();
-
 	napi = netdev_napi_by_id_lock(genl_info_net(info), napi_id);
 	if (napi) {
 		err = netdev_nl_napi_set_config(napi, info);
@@ -369,8 +361,6 @@ int netdev_nl_napi_set_doit(struct sk_buff *skb, struct genl_info *info)
 		err = -ENOENT;
 	}
 
-	rtnl_unlock();
-
 	return err;
 }