Subject: Re: [PATCH net-next v10 3/4] net sched actions: dump more than TCA_ACT_MAX_PRIO actions per batch

From: Jiri Pirko <[email-masked]>
Date: Mon, 12 Jun 2017 13:47:51 +0200

Mon, Jun 12, 2017 at 01:16:05PM CEST, [email-masked] wrote:
>On 17-06-11 10:13 AM, Jiri Pirko wrote:
>> Sun, Jun 11, 2017 at 01:53:45PM CEST, [email-masked] wrote:
>[..]
>> > @@ -1168,14 +1185,24 @@ static int tc_dump_action(struct sk_buff *skb, struct netlink_callback *cb)
>> > 	if (a_o == NULL)
>> > 		return 0;
>> > 
>> > +	if (tb[TCA_ROOT_FLAGS])
>> > +		nla_memcpy(&select_flags, tb[TCA_ROOT_FLAGS],
>> > +			   sizeof(select_flags));
>> 
>> Please introduce a helper for this attr type in patch 1:
>> 
>> u32 select_flags;
>> 
>> select_flags = nla_get_flag_bits_values(tb[TCA_ROOT_FLAGS])
>> 
>
>This also is not useful.
>It happens to be ok for this use case but not for the
>general case. i.e.
>We need to get the whole struct not just the values
>and use the selector to pick what bits are affected.
>Example if bit X is set to 1 in selector and bit X in value
>is 0, then we set the kernel's bit X to 0.

Sure, have another helper for selector then.
Or, you can have:

	struct nla_flag_bits *fb;
	fb = nla_get_flag_bits(tb[TCA_ROOT_FLAGS]);

Or all 3 helpers. My point is, it is a specific netlink attribute with
specific format, it should have get/put helpers.