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SubjectRE: [EXTERNAL] Re: [Patch v7 5/5] RDMA/mana_ib: Send event to qp
Date

> -----Original Message-----
> From: Jason Gunthorpe <jgg@ziepe.ca>
> Sent: Monday, October 23, 2023 11:24 AM
> To: sharmaajay@linuxonhyperv.com
> Cc: Long Li <longli@microsoft.com>; Leon Romanovsky <leon@kernel.org>;
> Dexuan Cui <decui@microsoft.com>; Wei Liu <wei.liu@kernel.org>; David S.
> Miller <davem@davemloft.net>; Eric Dumazet <edumazet@google.com>;
> Jakub Kicinski <kuba@kernel.org>; Paolo Abeni <pabeni@redhat.com>; linux-
> rdma@vger.kernel.org; linux-hyperv@vger.kernel.org;
> netdev@vger.kernel.org; linux-kernel@vger.kernel.org; Ajay Sharma
> <sharmaajay@microsoft.com>
> Subject: [EXTERNAL] Re: [Patch v7 5/5] RDMA/mana_ib: Send event to qp
>
> On Mon, Oct 16, 2023 at 03:12:02PM -0700,
> sharmaajay@linuxonhyperv.com wrote:
>
> > diff --git a/drivers/infiniband/hw/mana/qp.c
> > b/drivers/infiniband/hw/mana/qp.c index ef3275ac92a0..19fae28985c3
> > 100644
> > --- a/drivers/infiniband/hw/mana/qp.c
> > +++ b/drivers/infiniband/hw/mana/qp.c
> > @@ -210,6 +210,8 @@ static int mana_ib_create_qp_rss(struct ib_qp
> *ibqp, struct ib_pd *pd,
> > wq->id = wq_spec.queue_index;
> > cq->id = cq_spec.queue_index;
> >
> > + xa_store(&mib_dev->rq_to_qp_lookup_table, wq->id, qp,
> GFP_KERNEL);
> > +
>
> A store with no erase?
>
> A load with no locking?
>
> This can't be right
>
> Jason

This wq->id is assigned from the HW and is guaranteed to be unique. May be I am not following why do we need a lock here. Can you please explain ?
Ajay

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