From: Leon Romanovsky <leon@kernel.org>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: YueHaibing <yuehaibing@huawei.com>,
liangwenpeng@huawei.com, liweihang@huawei.com,
dledford@redhat.com, chenglang@huawei.com,
linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH -next] RDMA/hns: Fix return in hns_roce_rereg_user_mr()
Date: Thu, 5 Aug 2021 15:30:15 +0300 [thread overview]
Message-ID: <YQvZ14oSAYEuSTA3@unreal> (raw)
In-Reply-To: <20210805122311.GJ543798@ziepe.ca>
On Thu, Aug 05, 2021 at 09:23:11AM -0300, Jason Gunthorpe wrote:
> On Thu, Aug 05, 2021 at 01:58:53PM +0300, Leon Romanovsky wrote:
>
> > > IMO, if ibv_rereg_mr failed, the mr is in undefined state, user
> > > needs to call ibv_dereg_mr in order to release it, so there no
> > > need to recover the original state.
> >
> > The thing is that it undefined state in the kernel. What will be if
> > user will change access_flags and try to use that "broken" MR
> > anyway? Will you catch it?
>
> rereg is not atomic, if the rereg fails in the middle the mr should be
> left in some safe state.
It is not the case in the hns flow, they leave such MR in limbo state.
>
> Jason
next prev parent reply other threads:[~2021-08-05 12:30 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-04 12:59 [PATCH -next] RDMA/hns: Fix return in hns_roce_rereg_user_mr() YueHaibing
2021-08-04 13:53 ` Leon Romanovsky
2021-08-05 2:36 ` YueHaibing
2021-08-05 3:40 ` Leon Romanovsky
2021-08-05 9:29 ` YueHaibing
2021-08-05 10:58 ` Leon Romanovsky
2021-08-05 12:23 ` Jason Gunthorpe
2021-08-05 12:30 ` Leon Romanovsky [this message]
2021-08-19 14:18 ` Jason Gunthorpe
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