Subject: Re: [patch net-next 3/5] net: sched: introduce block mechanism to handle netif_keep_dst calls

From: Daniel Borkmann <[email-masked]>
Date: Fri, 03 Nov 2017 21:15:54 +0100

On 11/03/2017 06:19 PM, Jiri Pirko wrote:
> From: Jiri Pirko <[email-masked]>
>
> Couple of classifiers call netif_keep_dst directly on q->dev. That is
> not possible to do directly for shared blocke where multiple qdiscs are
> owning the block. So introduce a infrastructure to keep track of the
> block owners in list and use this list to implement block variant of
> netif_keep_dst.
>
> Signed-off-by: Jiri Pirko <[email-masked]>
[...]
> +struct tcf_block_owner_item {
> +	struct list_head list;
> +	struct Qdisc *q;
> +	enum tcf_block_binder_type binder_type;
> +};
> +
> +static void
> +tcf_block_owner_netif_keep_dst(struct tcf_block *block,
> +			       struct Qdisc *q,
> +			       enum tcf_block_binder_type binder_type)
> +{
> +	if (block->keep_dst &&
> +	    binder_type != TCF_BLOCK_BINDER_TYPE_CLSACT_INGRESS)

Why we need to keep dst on TCF_BLOCK_BINDER_TYPE_CLSACT_EGRESS ?
I presume this enum means sch_handle_egress() ? dst is dropped
later ...

> +		netif_keep_dst(qdisc_dev(q));
> +}
> +
> +void tcf_block_netif_keep_dst(struct tcf_block *block)
> +{
> +	struct tcf_block_owner_item *item;
> +
> +	block->keep_dst = true;
> +	list_for_each_entry(item, &block->owner_list, list)