Re: [PATCH] IB/core: Don't drain the receive queue for srq attached queue-pair

[Bart Van Assche <bart.vanassche-XdAiOPVOjttBDgjK7y7TUQ@public.gmane.org>]

On 04/26/2016 09:00 AM, Steve Wise wrote:
> On 4/26/2016 10:55 AM, Chuck Lever wrote:
>>> On Apr 26, 2016, at 11:43 AM, Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org> wrote:
>>>
>>> Just curious: what takes care of draining SRQs when we unregister them
>>> after all queues are gone?
>>
>> Conversely, I would think that a consumer that uses SRQ
>> would want a similar drain mechanism to guarantee there
>> are no more posted Receives for the associated QP, and
>> thus it is safe to destroy it.
> 
> I don't think there is anything now that handles draining an SRQ, nor 
> ensuring a QP's RQEs are completed/consumed from its SRQ when draining 
> the QP.  Sounds like work is needed here.
> 
> But are there any kernel SRQ consumers at this point?

I think the following two:

$ git grep -nHE '(ib|rdma)_create_srq' drivers/infiniband/ulp
drivers/infiniband/ulp/ipoib/ipoib_cm.c:1521:	priv->cm.srq = ib_create_srq(priv->pd, &srq_init_attr);
drivers/infiniband/ulp/srpt/ib_srpt.c:2723:	sdev->srq = ib_create_srq(sdev->pd, &srq_attr);

Bart.

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