From: Jason Gunthorpe <jgg@nvidia.com>
To: Tony Krowiak <akrowiak@linux.ibm.com>
Cc: linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
borntraeger@de.ibm.com, cohuck@redhat.com,
pasic@linux.vnet.ibm.com, jjherne@linux.ibm.com,
alex.williamson@redhat.com, kwankhede@nvidia.com,
frankja@linux.ibm.com, david@redhat.com, imbrenda@linux.ibm.com,
hca@linux.ibm.com
Subject: Re: [PATCH v4 2/2] s390/vfio-ap: control access to PQAP(AQIC) interception handler
Date: Tue, 25 May 2021 12:00:54 -0300 [thread overview]
Message-ID: <20210525150054.GA1002214@nvidia.com> (raw)
In-Reply-To: <ac5cfe4a-a61b-2226-58aa-a5ea761180be@linux.ibm.com>
On Tue, May 25, 2021 at 10:59:25AM -0400, Tony Krowiak wrote:
> > But this is alot of complicated and unused code to solve a lock
> > ordering problem..
>
> If you have a better solution, I'm all ears. I've been down this
> road a couple of times now and solving lock ordering for
> multiple asynchronous processes is not trivial. This seems like
> a reasonable solution and provides for flexibility for including
> additional hooks to handle interception of other AP instructions.
Lock ordering is very trivial. In this case you have to always hold
the hook lock before obtaining the matrix_dev lock. From what I
remember there was only one error on the set path where they were
ordered wrong
Jason
next prev parent reply other threads:[~2021-05-25 15:01 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-21 19:36 [PATCH v4 0/2] s390/vfio-ap: fix memory leak in mdev remove callback Tony Krowiak
2021-05-21 19:36 ` [PATCH v4 1/2] " Tony Krowiak
2021-05-25 13:03 ` Halil Pasic
2021-05-25 13:22 ` Tony Krowiak
2021-05-26 12:37 ` Tony Krowiak
2021-05-21 19:36 ` [PATCH v4 2/2] s390/vfio-ap: control access to PQAP(AQIC) interception handler Tony Krowiak
2021-05-23 22:57 ` Jason Gunthorpe
2021-05-25 14:59 ` Tony Krowiak
2021-05-25 15:00 ` Jason Gunthorpe [this message]
2021-05-24 14:37 ` Jason J. Herne
2021-05-25 13:16 ` Tony Krowiak
2021-05-25 13:19 ` Jason Gunthorpe
2021-05-25 15:08 ` Tony Krowiak
2021-05-25 15:11 ` Jason Gunthorpe
2021-05-25 15:56 ` Tony Krowiak
2021-05-25 16:29 ` Jason Gunthorpe
2021-05-27 2:28 ` Tony Krowiak
2021-05-27 11:24 ` Jason Gunthorpe
2021-05-25 13:24 ` Jason J. Herne
2021-05-25 13:26 ` Jason Gunthorpe
2021-05-25 14:07 ` Jason J. Herne
2021-05-25 14:16 ` Jason Gunthorpe
2021-06-14 7:51 ` [PATCH v4 0/2] s390/vfio-ap: fix memory leak in mdev remove callback Christian Borntraeger
2021-06-16 14:24 ` Tony Krowiak
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