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From: Jason Gunthorpe <jgg@nvidia.com>
To: Bob Pearson <rpearsonhpe@gmail.com>
Cc: Leon Romanovsky <leon@kernel.org>, <zyjzyj2000@gmail.com>,
	<linux-rdma@vger.kernel.org>, Frank Zago <frank.zago@hpe.com>
Subject: Re: [PATCH for-next] RDMA/rxe: Fix ib_device reference counting (again)
Date: Mon, 1 Mar 2021 13:35:40 -0400	[thread overview]
Message-ID: <20210301173540.GN4247@nvidia.com> (raw)
In-Reply-To: <b1fec0dc-6b4a-8364-2b90-a4ef5cd839c6@gmail.com>

On Mon, Mar 01, 2021 at 10:54:21AM -0600, Bob Pearson wrote:

> I agree that ib_device_get/put is attempting to solve a problem that it not
> really very critical since ib_device is very unlikely to be shut down in the
> middle of a data transfer. The driver never worried about this for years.
> But now that it's been put on the table it should be done right. A data packet
> arriving is completely independent of the verbs API which *could* delete all the
> QPs and shut down the HCA while it was wondering around the universe or worse
> yet while the packet is being processed.

If driver shutdown can guarentee that all pointers involved in
multicast are revoked before shutdown can finish then you don't need
this refcounting.

It was only brought up because the API that returns the ib_device from
the netdev requires the refcounts as it is general purpose

Jason

  reply	other threads:[~2021-03-01 17:46 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-14 22:26 [PATCH for-next] RDMA/rxe: Fix ib_device reference counting (again) Bob Pearson
2021-02-15  3:46 ` Zhu Yanjun
2021-02-15  5:59 ` Leon Romanovsky
2021-02-26 23:28 ` Bob Pearson
2021-02-26 23:33   ` Jason Gunthorpe
2021-02-27  0:02     ` Bob Pearson
2021-02-27  8:43       ` Leon Romanovsky
2021-02-28 17:04         ` Bob Pearson
2021-03-01  7:24           ` Leon Romanovsky
2021-03-01 16:54             ` Bob Pearson
2021-03-01 17:35               ` Jason Gunthorpe [this message]
2021-03-01 18:20                 ` Pearson, Robert B
2021-03-01 18:27                   ` Jason Gunthorpe
2021-03-02  8:11                     ` Leon Romanovsky
2021-03-01  7:42           ` Zhu Yanjun
2021-03-02  5:19 ` Zhu Yanjun
2021-03-02  7:26   ` Robert Pearson

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