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From:   Menglong Dong <menglong8.dong@gmail.com>
Date:   Sun, 6 Jun 2021 22:40:49 +0800
Message-ID: <CADxym3a_iTXWWOxK1vfNxuWRh7ve4vOWZERho7jTVUkxc2Z_rQ@mail.gmail.com>
Subject: Re: [PATCH net-next] net: tipc: fix FB_MTU eat two pages
To:     Jon Maloy <jmaloy@redhat.com>
Cc:     ying.xue@windriver.com, David Miller <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        netdev <netdev@vger.kernel.org>,
        tipc-discussion@lists.sourceforge.net,
        Menglong Dong <dong.menglong@zte.com.cn>,
        Zeal Robot <zealci@zte.com.cn>
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On Sat, Jun 5, 2021 at 10:25 PM Jon Maloy <jmaloy@redhat.com> wrote:
>
>
>
> On 6/4/21 9:28 PM, Menglong Dong wrote:
> > Hello Maloy,
> >
> > On Sat, Jun 5, 2021 at 3:20 AM Jon Maloy <jmaloy@redhat.com> wrote:
> >>
> > [...]
> >> Please don't add any extra file just for this little fix. We have enough
> >> files.
> >> Keep the macros in msg.h/c where they used to be.  You can still add
> >> your copyright line to those files.
> >> Regarding the macros kept inside msg.c, they are there because we design
> >> by the principle of minimal exposure, even among our module internal files.
> >> Otherwise it is ok.
> >>
> > I don't want to add a new file too, but I found it's hard to define FB_MTU. I
> > tried to define it in msg.h, and 'crypto.h' should be included, which
> > 'BUF_HEADROOM' is defined in. However, 'msg.h' is already included in
> > 'crypto.h', so it doesn't work.
> >
> > I tried to define FB_MTU in 'crypto.h', but it feels weird to define
> > it here. And
> > FB_MTU is also used in 'bcast.c', so it can't be defined in 'msg.c'.
> >
> > I will see if there is a better solution.
> I think we can leverage the fact that this by definition is a node local
> message, and those are never encrypted.
> So, if you base FB_MTU on the non-crypto versions of BUF_HEADROOM and
> BUF_TAILROOM we should be safe.
> That will even give us better utilization of the space available.
>

Ok, that sounds nice. I'll make a V2 based on that.

Thanks!
Menglong Dong