Subject: Re: [RFC PATCH net-next] net: sched: flower: refactor reoffload for concurrent access

From: Vlad Buslov <[email-masked]>
Date: Wed, 17 Apr 2019 07:29:36 +0000

On Wed 17 Apr 2019 at 00:49, Jakub Kicinski <[email-masked]> wrote:
> On Tue, 16 Apr 2019 17:20:47 +0300, Vlad Buslov wrote:
>> @@ -1551,6 +1558,10 @@ static int fl_change(struct net *net, struct sk_buff *in_skb,
>>  		goto errout_mask;
>>
>>  	if (!tc_skip_hw(fnew->flags)) {
>> +		spin_lock(&tp->lock);
>> +		list_add(&fnew->hw_list, &head->hw_filters);
>> +		spin_unlock(&tp->lock);
>> +
>>  		err = fl_hw_replace_filter(tp, fnew, rtnl_held, extack);
>>  		if (err)
>>  			goto errout_ht;
>
> Duplicated deletes should be fine, but I'm not sure same is true for
> adds.  Won't seeing an add with the same cookie twice confuse drivers?
>
> There's also the minor issue of offloaded count being off in that
> case :)

Hmmm, okay. Rejecting duplicate cookies should be a trivial change to
drivers though. Do you see any faults with this approach in general?