Jakub Kicinski <[email protected]> writes:
> 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.
Hmm, OK! My take was the it was mostly moving stuff.
> 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'
Thanks! (I've looked thru all the pw complaints, and fixed locally!)
>
>> @@ -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
Indeed! I think that would work, and that'd be cleaner!
Cheers!
