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Date:      Fri, 19 May 2017 09:18:30 +0800
From:      Sepherosa Ziehau <sephe@freebsd.org>
To:        Hans Petter Selasky <hps@selasky.org>
Cc:        Oleg Bulyzhin <oleg@freebsd.org>, src-committers <src-committers@freebsd.org>,  svn-src-all@freebsd.org, svn-src-head@freebsd.org, araujo@freebsd.org
Subject:   Re: svn commit: r305177 - head/sys/net
Message-ID:  <CAMOc5cy69OEqnuvAAUmYLMFEoAsjtmCo4Y5ORfBuH44RVBL4Fg@mail.gmail.com>
In-Reply-To: <c2dc3966-bf61-e240-4a4f-5057ff94d22f@selasky.org>
References:  <201609010632.u816WZUj025186@repo.freebsd.org> <20170518140403.GA54405@lath.RINET.ru> <355478da-ed4d-60bb-bb4e-144a694e28b8@selasky.org> <20170518150030.GA55481@lath.RINET.ru> <c2dc3966-bf61-e240-4a4f-5057ff94d22f@selasky.org>

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Oh, my fault.  I will revert it.

On Thu, May 18, 2017 at 11:11 PM, Hans Petter Selasky <hps@selasky.org> wrote:
> On 05/18/17 17:00, Oleg Bulyzhin wrote:
>>
>> On Thu, May 18, 2017 at 04:25:01PM +0200, Hans Petter Selasky wrote:
>>>
>>> On 05/18/17 16:04, Oleg Bulyzhin wrote:
>>>>
>>>> On Thu, Sep 01, 2016 at 06:32:35AM +0000, Sepherosa Ziehau wrote:
>>>>>
>>>>> Author: sephe
>>>>> Date: Thu Sep  1 06:32:35 2016
>>>>> New Revision: 305177
>>>>> URL: https://svnweb.freebsd.org/changeset/base/305177
>>>>>
>>>>> Log:
>>>>>     net/vlan: Shift for pri is 13 (pri mask 0xe000) not 1.
>>>>>         Reviewed by:    araujo, hps
>>>>>     MFC after:  1 week
>>>>>     Sponsored by:       Microsoft
>>>>>     Differential Revision:      https://reviews.freebsd.org/D7710
>>>>>
>>>>> Modified:
>>>>>     head/sys/net/ethernet.h
>>>>>
>>>>> Modified: head/sys/net/ethernet.h
>>>>>
>>>>> ==============================================================================
>>>>> --- head/sys/net/ethernet.h     Thu Sep  1 06:05:08 2016
>>>>> (r305176)
>>>>> +++ head/sys/net/ethernet.h     Thu Sep  1 06:32:35 2016
>>>>> (r305177)
>>>>> @@ -92,7 +92,7 @@ struct ether_vlan_header {
>>>>>    #define      EVL_PRIOFTAG(tag)       (((tag) >> 13) & 7)
>>>>>    #define      EVL_CFIOFTAG(tag)       (((tag) >> 12) & 1)
>>>>>    #define      EVL_MAKETAG(vlid, pri, cfi)
>>>>> \
>>>>> -       ((((((pri) & 7) << 1) | ((cfi) & 1)) << 12) | ((vlid) &
>>>>> EVL_VLID_MASK))
>>>>> +       ((((((pri) & 7) << 13) | ((cfi) & 1)) << 12) | ((vlid) &
>>>>> EVL_VLID_MASK))
>>>>>       /*
>>>>>     *  NOTE: 0x0000-0x05DC (0..1500) are generally IEEE 802.3 length
>>>>> fields.
>>>>
>>>>
>>>> Please revert this one. It's just plain wrong and previous one was ok.
>>>>
>>>
>>> Hi,
>>>
>>> Can you explain a bit more what is wrong?
>>>
>>>> If you care about readability it should be:
>>>> ((((pri) & 7) << 13) | (((cfi) & 1) << 12) | ((vlid) & EVL_VLID_MASK))
>>>
>>>
>>> Isn't this exactly what the patch is doing? -R ???
>>
>>
>> Current version is shifting pri out of uint16. If you examine parentheses:
>> pri is shifted left 13, then 12.
>> Original version did it right (shift 1, then 12 (total 13)).
>>
>
> Hi Oleg,
>
> I see. The VLAN priority is then always zero after this change.
>
> I'll let Sepherosa handle the revert and/or readability update.
>
> --HPS



-- 
Tomorrow Will Never Die



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