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From:   Cong Wang <xiyou.wangcong@gmail.com>
Date:   Sun, 19 Sep 2021 16:52:35 -0700
Message-ID: <CAM_iQpXcqpEFpnyX=wLQFTWJBjWiAMofighQkpnrV2a0Fh83AQ@mail.gmail.com>
Subject: Re: [PATCH net-next] net: socket: add the case sock_no_xxx support
To:     Yajun Deng <yajun.deng@linux.dev>
Cc:     Jakub Kicinski <kuba@kernel.org>,
        David Miller <davem@davemloft.net>,
        Linux Kernel Network Developers <netdev@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
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On Sat, Sep 18, 2021 at 5:11 AM <yajun.deng@linux.dev> wrote:
>
> September 18, 2021 9:33 AM, "Jakub Kicinski" <kuba@kernel.org> wrote:
>
> > On Thu, 16 Sep 2021 20:29:43 +0800 Yajun Deng wrote:
> >
> >> Those sock_no_{mmap, socketpair, listen, accept, connect, shutdown,
> >> sendpage} functions are used many times in struct proto_ops, but they are
> >> meaningless. So we can add them support in socket and delete them in struct
> >> proto_ops.
> >
> > So the reason to do this is.. what exactly?
> >
> > Removing a couple empty helpers (which is not even part of this patch)?
> >
> > I'm not sold, sorry.
>
> When we define a struct proto_ops xxx, we only need to assign meaningful member variables that we need.
> Those {mmap, socketpair, listen, accept, connect, shutdown, sendpage} members we don't need assign
> it if we don't need. We just need do once in socket, not in every struct proto_ops.
>
> These members are assigned meaningless values far more often than meaningful ones, so this patch I used likely(!!sock->ops->xxx) for this case. This is the reason why I send this patch.

But you end up adding more code:

 1 file changed, 58 insertions(+), 13 deletions(-)

I don't see this as a gain from any perspective.

Thanks.