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Date:   Mon, 16 Nov 2020 18:16:00 +0100
From:   Florian Westphal <fw@strlen.de>
To:     Randy Dunlap <rdunlap@infradead.org>
Cc:     Jakub Kicinski <kuba@kernel.org>, Florian Westphal <fw@strlen.de>,
        Matthieu Baerts <matthieu.baerts@tessares.net>,
        linux-kernel@vger.kernel.org, kernel test robot <lkp@intel.com>,
        Aleksandr Nogikh <nogikh@google.com>,
        Willem de Bruijn <willemb@google.com>,
        linux-next@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH net-next v4] net: linux/skbuff.h: combine SKB_EXTENSIONS
 + KCOV handling
Message-ID: <20201116171600.GD22792@breakpoint.cc>
References: <20201116031715.7891-1-rdunlap@infradead.org>
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 <20201116143121.GC22792@breakpoint.cc>
 <20201116073013.24d45385@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
 <53e73344-3a3a-4a11-9914-8490efa1a3b9@infradead.org>
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Randy Dunlap <rdunlap@infradead.org> wrote:
> On 11/16/20 7:30 AM, Jakub Kicinski wrote:
> > On Mon, 16 Nov 2020 15:31:21 +0100 Florian Westphal wrote:
> >>>> @@ -4151,12 +4150,11 @@ enum skb_ext_id {
> >>>>   #if IS_ENABLED(CONFIG_MPTCP)
> >>>>   	SKB_EXT_MPTCP,
> >>>>   #endif
> >>>> -#if IS_ENABLED(CONFIG_KCOV)
> >>>>   	SKB_EXT_KCOV_HANDLE,
> >>>> -#endif  
> >>>
> >>> I don't think we should remove this #ifdef: the number of extensions are
> >>> currently limited to 8, we might not want to always have KCOV there even if
> >>> we don't want it. I think adding items in this enum only when needed was the
> >>> intension of Florian (+cc) when creating these SKB extensions.
> >>> Also, this will increase a tiny bit some structures, see "struct skb_ext()".  
> >>
> >> Yes, I would also prefer to retrain the ifdef.
> >>
> >> Another reason was to make sure that any skb_ext_add(..., MY_EXT) gives
> >> a compile error if the extension is not enabled.
> > 
> > Oh well, sorry for taking you down the wrong path Randy!
> 
> No problem.
> So we are back to v2, right?

Yes, you can still drop the line

>> +#if IS_ENABLED(CONFIG_KCOV) && IS_ENABLED(CONFIG_SKB_EXTENSIONS)

for enum skb_ext_id (alreadyt under SKB_EXTENSIONS).

Other than that v2 looks good to me.

Thanks!