APPLIED: ACK Lucid SRU: UBUNTU: SAUCE: igb: Protect stats update

[Tim Gardner]

On 09/23/2011 06:36 AM, Stefan Bader wrote:
> On 21.09.2011 16:56, Tim Gardner wrote:
>> On 09/21/2011 08:48 AM, Stefan Bader wrote:
>>> On 21.09.2011 16:43, Tim Gardner wrote:
>>>> On 09/21/2011 08:29 AM, Stefan Bader wrote:
>>>>> On 21.09.2011 15:43, Tim Gardner wrote:
>>>>>> This patch is a partial backport of upstream
>>>>>> 12dcd86b75d571772512676ab301279952efc0b0. Its purpose is twofold; 1) Protect
>>>>>> simultaneous readers and writers, 2) refresh statistics when read from
>>>>>> ethtool.
>>>>>>
>>>>>> rtg
>>>>>>
>>>>> Wondering whether there is any chance of a running user task holding the
>>>>> spinlock by that watchdog work...
>>>>>
>>>>
>>>> If by 'running user task' you mean the ethtool interface, then yes the lock
>>>> _should_ be held whilst the statistics update is in progress.
>>>>
>>> Yeah, no (if that makes any sense). I was more wondering whether the lock may be
>>> tried to be taken from the watchdog task (scheduled_work) while a user-space
>>> process does something like ethtool on the same cpu...
>>>
>>
>> That could only happen if CONFIG_PREEMPT=y, in which case the spin lock logic
>> should do the right thing.
>>
>> rtg
>
> With this mornigns discussion I' ack it as well. Just seems already applied
>

It got applied by accident. Now reapplied with proper acknowledgements.
-- 
Tim Gardner tim.gardner at canonical.com