Re: [dpdk-dev] [PATCH 2/2] kni: fix rtnl deadlocks and race conditions v4

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 3/1/2021 4:38 PM, Stephen Hemminger wrote:
> On Mon, 1 Mar 2021 11:10:01 +0300
> Igor Ryzhov <iryzhov@nfware.com> wrote:
> 
>> Stephen,
>>
>> No, I don't have a better proposal, but I think it is not correct to change
>> the behavior of KNI (making link down without a real response).
>> Even though we know that communicating with userspace under rtnl_lock is a
>> bad idea, it works as it is for many years already.
>>
>> Elad,
>>
>> I agree with you that KNI should be removed from the main tree if it is not
>> possible to fix this __dev_close_many issue.
>> There were discussions about this multiple times already, but no one is
>> working on this AFAIK.
>> Last time the discussion was a month ago:
>> https://www.mail-archive.com/dev@dpdk.org/msg196033.html
>>
>> Igor
> 
> The better proposal would be to make DPDK virtio smarter.
> There already is virtio devices that must handle this (VDPA) etc.
> And when you can control link through virtio, then put a big warning
> in KNI that says "Don't use this"
> 

Hi Igor, Elad,

I think it is reasonable to do the ifdown as async to solve the problem,
still we can make sync default, and async with kernel parameter, to cover both case.

I will put more details on the patches.