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Date:   Mon, 7 Jun 2021 14:03:16 +0300
From:   Leon Romanovsky <leon@kernel.org>
To:     Zhu Yanjun <zyjzyj2000@gmail.com>
Cc:     Bob Pearson <rpearsonhpe@gmail.com>,
        Jason Gunthorpe <jgg@nvidia.com>,
        RDMA mailing list <linux-rdma@vger.kernel.org>
Subject: Re: [PATCH for-next] RDMA/rxe: Fix qp reference counting for atomic
 ops
Message-ID: <YL389Dqd8+akhb1i@unreal>
References: <20210604230558.4812-1-rpearsonhpe@gmail.com>
 <CAD=hENcwwjS8X2R24+cFRyyrA5_k=F5LuC4bx1tzCVW969uvuQ@mail.gmail.com>
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On Mon, Jun 07, 2021 at 04:16:37PM +0800, Zhu Yanjun wrote:
> On Sat, Jun 5, 2021 at 7:07 AM Bob Pearson <rpearsonhpe@gmail.com> wrote:
> >
> > Currently the rdma_rxe driver attempts to protect atomic responder
> > resources by taking a reference to the qp which is only freed when the
> > resource is recycled for a new read or atomic operation. This means that
> > in normal circumstances there is almost always an extra qp reference
> > once an atomic operation has been executed which prevents cleaning up
> > the qp and associated pd and cqs when the qp is destroyed.
> >
> > This patch removes the call to rxe_add_ref() in send_atomic_ack() and the
> > call to rxe_drop_ref() in free_rd_atomic_resource(). If the qp is
> 
> Not sure if it is a good way to fix this problem by removing the call
> to rxe_add_ref.
> Because taking a reference to the qp is to protect atomic responder resources.
> 
> Removing rxe_add_ref is to decrease the protection of the atomic
> responder resources.

All those rxe_add_ref/rxe_drop_ref in RXE are horrid. It will be good to delete them all.

Thanks