[PATCH 0/1] mv643xx_eth: Disable TSO by default

[Ezequiel Garcia]

On 05/29/2015 03:16 AM, Dr. Uwe Meyer-Gruhl wrote:
>> On Wed, Nov 05, 2014 at 08:39:26AM +0000, Ian Campbell wrote:
>>> On Tue, 2014-11-04 at 15:20 +0100, Karl Beldan wrote:
>>>> On Sat, Nov 01, 2014 at 12:30:19PM -0300, Ezequiel Garcia wrote:
>>>>> Several users ([1], [2]) have been reporting data corruption
>>>>> with TSO on Kirkwood platforms (i.e. using the mv643xx_eth
>>>>> driver).
>>>>>
>>>>> Until we manage to find what's causing this, this simple patch 
>>>>> will make
>>>>> the TSO path disabled by default. This patch should be queued
> for stable,
>>>>> fixing the TSO feature introduced in v3.16.
>>>>>
>>>>> The corruption itself is very easy to reproduce: checkingmd5sum on
>>>>> a mounted
>>>>> NFS directory gives a different result each time. Same tests  using
>>>>> the mvneta
>>>>> driver (Armada 370/38x/XP SoC) pass with no issues.
>>>>>
>>>>> Frankly, I'm a bit puzzled about this, and so any ideas ordebugging
>>>>> hints
>>>>> are well received.
>>>>>
>>>>
>>>> Hi,
>>>>
>>>> Can you try this :
>>>
>>> It fixes things for me, thanks!
>>>
>>> Tested-by: Ian Campbell <ijc at hellion.org.uk>
>>>
>>
>> Good thing, thanks for your feedbak Ian !
>>
>> Karl --
> 
> That would be a good thing - although: Neither the patch to disable TSO
> altogether nor the one that fixes the underlying problem actually made
> it to the official kernel source tree, so it is still present in all
> kernels > 3.16 - I just stumbled over this in the current 4.0.4 version.
> 
> The fixes in the thread
> http://marc.info/?l=linux-netdev&m=141517941900547&w=2 are not
> applicable any more to the current driver from the 4.0 kernel, as the
> whole respective logic seems to have been changed meanwhile, sadly
> without fixing the problem. Disabling TSO completely still works, though.
> 
> Can someone in the know please suggest a working fix to the kernel
> maintainers, preferably one that does not resort to disable TSO?
> 

Hello Uwe,

Thanks for reporting. There wasn't any patch left behind. The above fix
was merged (and applied to the stable tree) as this commit:

commit 2c2a9cbd64387d6b70ac5db013e9bfe9412c7354
Author: Karl Beldan <karl.beldan at rivierawaves.com>
Date:   Wed Nov 5 15:32:59 2014 +0100

    net: mv643xx_eth: reclaim TX skbs only when released by the HW

Can you explain in detail what sort of problem are you running into,
which kernel version are you using, etc.?
-- 
Ezequiel Garcia, VanguardiaSur
www.vanguardiasur.com.ar