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From: Cong Wang <xiyou.wangcong@gmail.com>
To: Zang MingJie <zealot0630@gmail.com>
Cc: Linux Kernel Network Developers <netdev@vger.kernel.org>,
	dev@openvswitch.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] net: preserve IP control block during GSO segmentation
Date: Mon, 11 Jan 2016 16:58:24 -0800	[thread overview]
Message-ID: <CAM_iQpUO4aE_UybNYrFw+u=LWnF3OcC5jQ+ADsK1XobjBwUeEA@mail.gmail.com> (raw)
In-Reply-To: <56935DB5.1030502@gmail.com>

On Sun, Jan 10, 2016 at 11:45 PM, Zang MingJie <zealot0630@gmail.com> wrote:
> On 01/08/2016 08:13 PM, David Laight wrote:
>>
>> You could set SKB_SGO_CB_OFFSET to sizeof ((skb)->cb) - sizeof (struct
>> skb_gso_cb)
>> so that the end of 'cb' is always used.
>> (Assuming the former is a multiple of 4.)
>>
>> It might be worth using an on-stack structure passed through as a separate
>> parameter - it doesn't look as though it has to be queued with the skb.
>> (Clearly a bigger change.)
>
>
> I would definitely prefer the stack structure.
>
> As a kernel developer, sometime I can hardly figure out which struct current
> cb is without debug it, and the worst they are not documented anywhere. I
> can hardly know the life time of the cb types.

NAK.

Skb control block was not designed to be used like a stack but like a union
for different layers, just that people begin to mess it up.

WARNING: multiple messages have this Message-ID (diff)
From: Cong Wang <xiyou.wangcong-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: Zang MingJie <zealot0630-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: dev-yBygre7rU0TnMu66kgdUjQ@public.gmane.org,
	Linux Kernel Network Developers
	<netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	LKML <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Re: [PATCH] net: preserve IP control block during GSO segmentation
Date: Mon, 11 Jan 2016 16:58:24 -0800	[thread overview]
Message-ID: <CAM_iQpUO4aE_UybNYrFw+u=LWnF3OcC5jQ+ADsK1XobjBwUeEA@mail.gmail.com> (raw)
In-Reply-To: <56935DB5.1030502-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

On Sun, Jan 10, 2016 at 11:45 PM, Zang MingJie <zealot0630@gmail.com> wrote:
> On 01/08/2016 08:13 PM, David Laight wrote:
>>
>> You could set SKB_SGO_CB_OFFSET to sizeof ((skb)->cb) - sizeof (struct
>> skb_gso_cb)
>> so that the end of 'cb' is always used.
>> (Assuming the former is a multiple of 4.)
>>
>> It might be worth using an on-stack structure passed through as a separate
>> parameter - it doesn't look as though it has to be queued with the skb.
>> (Clearly a bigger change.)
>
>
> I would definitely prefer the stack structure.
>
> As a kernel developer, sometime I can hardly figure out which struct current
> cb is without debug it, and the worst they are not documented anywhere. I
> can hardly know the life time of the cb types.

NAK.

Skb control block was not designed to be used like a stack but like a union
for different layers, just that people begin to mess it up.
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  reply	other threads:[~2016-01-12  0:58 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-08 12:00 [PATCH] net: preserve IP control block during GSO segmentation Konstantin Khlebnikov
2016-01-08 12:00 ` Konstantin Khlebnikov
2016-01-08 12:10 ` Konstantin Khlebnikov
2016-01-08 12:10   ` Konstantin Khlebnikov
2016-01-08 12:11 ` Thadeu Lima de Souza Cascardo
2016-01-08 12:13 ` David Laight
2016-01-08 12:13   ` David Laight
2016-01-08 12:20   ` Thadeu Lima de Souza Cascardo
2016-01-08 12:20     ` Thadeu Lima de Souza Cascardo
2016-01-11  7:45   ` Zang MingJie
2016-01-11  7:45   ` Zang MingJie
2016-01-11  7:45   ` Zang MingJie
2016-01-12  0:58     ` Cong Wang [this message]
2016-01-12  0:58       ` Cong Wang
2016-01-08 12:24 ` kbuild test robot
2016-01-08 12:24   ` kbuild test robot

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