netdev - Re: [PATCH net-next 2/2] net: cls_u32: Add support for skip-sw flag to tc u32 classifier.

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Message-Id: <20160511.192316.1290350535833930948.davem@davemloft.net>
Date:	Wed, 11 May 2016 19:23:16 -0400 (EDT)
From:	David Miller <davem@...emloft.net>
To:	sridhar.samudrala@...el.com
Cc:	john.r.fastabend@...el.com, netdev@...r.kernel.org
Subject: Re: [PATCH net-next 2/2] net: cls_u32: Add support for skip-sw
 flag to tc u32 classifier.

From: Sridhar Samudrala <sridhar.samudrala@...el.com>
Date: Mon,  9 May 2016 12:18:44 -0700

> On devices that support TC U32 offloads, this flag enables a filter to be
> added only to HW. skip-sw and skip-hw are mutually exclusive flags. By
> default without any flags, the filter is added to both HW and SW, but no
> error checks are done in case of failure to add to HW. With skip-sw,
> failure to add to HW is treated as an error.

I really want you to provide a "[PATCH net-next 0/2]" header posting
explaining what this series is doing, and why.

This is a core semantic issue, and we have to make sure all amongst us
that we are all comfortable with exporting the offloadability controls
in the way you are implementing them.

Also:

> @@ -871,10 +889,15 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
>  			return err;
>  		}
>  
> +		err = u32_replace_hw_knode(tp, new, flags);
> +		if (err) {
> +			u32_destroy_key(tp, new, false);
> +			return err;
> +		}
> +
>  		u32_replace_knode(tp, tp_c, new);
>  		tcf_unbind_filter(tp, &n->res);
>  		call_rcu(&n->rcu, u32_delete_key_rcu);
> -		u32_replace_hw_knode(tp, new, flags);
>  		return 0;
>  	}
>  

Are you sure this reordering is OK?