On Tue, 10 Mar 2026 11:47:31 +0100 Björn Töpel wrote:
> The per-PHY specific dump functions share a lot functionality of with
> the default dumpit infrastructure, but does not share the actual code.
> By introducing a new sub-iterator function, the two dumpit variants
> can be folded into one set of functions.
>
> Add a new dump_one_dev callback in ethnl_request_ops. When
> ops->dump_one_dev is set, ethnl_default_start() saves the target
> device's ifindex for filtered dumps, and ethnl_default_dumpit()
> delegates per-device iteration to the callback instead of calling
> ethnl_default_dump_one() directly. No separate start/dumpit/done
> functions are needed.
>
> For the existing per-PHY commands (PSE, PLCA, PHY, MSE), the shared
> ethnl_perphy_dump_one_dev helper provides the xa_for_each_start loop
> over the device's PHY topology.
>
> This prepares the ethtool infrastructure for other commands that need
> similar per-device sub-iteration.
Feels like this could be split into two patches for ease of review.
Warning: net/ethtool/netlink.h:441 struct member 'dump_one_dev' not described
in 'ethnl_request_ops'
Warning: net/ethtool/netlink.h:441 struct member 'dump_one_dev' not described
in 'ethnl_request_ops'
> @@ -616,17 +580,41 @@ static int ethnl_default_dumpit(struct sk_buff *skb,
> struct netlink_callback *cb)
> {
> struct ethnl_dump_ctx *ctx = ethnl_dump_context(cb);
> + const struct genl_info *info = genl_info_dump(cb);
> struct net *net = sock_net(skb->sk);
> netdevice_tracker dev_tracker;
> struct net_device *dev;
> int ret = 0;
>
> + if (ctx->ops->dump_one_dev && ctx->ifindex) {
> + dev = netdev_get_by_index(net, ctx->ifindex, &dev_tracker,
> + GFP_KERNEL);
> + if (!dev)
> + return -ENODEV;
> +
> + ctx->req_info->dev = dev;
> + ret = ctx->ops->dump_one_dev(skb, ctx, &ctx->pos_sub, info);
> +
> + if (ret < 0 && ret != -EOPNOTSUPP && likely(skb->len))
> + ret = skb->len;
> +
> + netdev_put(dev, &dev_tracker);
> + return ret;
> + }
> +
> rcu_read_lock();
> for_each_netdev_dump(net, dev, ctx->pos_ifindex) {
> netdev_hold(dev, &dev_tracker, GFP_ATOMIC);
> rcu_read_unlock();
>
> - ret = ethnl_default_dump_one(skb, dev, ctx, genl_info_dump(cb));
> + if (ctx->ops->dump_one_dev) {
> + ctx->req_info->dev = dev;
> + ret = ctx->ops->dump_one_dev(skb, ctx, &ctx->pos_sub,
> + info);
> + ctx->req_info->dev = NULL;
> + } else {
> + ret = ethnl_default_dump_one(skb, dev, ctx, info);
> + }
>
> rcu_read_lock();
> netdev_put(dev, &dev_tracker);
Not sure if it works here but another way to implementing single dump
and a loop dump concisely is to init both ifindex and pos_ifindex when
request is parsed and then add
if (ctx->ifindex && ctx->ifindex != ctx->pos_ifindex)
break;
at the start of the loop. That way the body of the loop doesn't have to
be repeated in a separate if
