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From: Jason Gunthorpe <jgg@nvidia.com>
To: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Matthew Rosato <mjrosato@linux.ibm.com>,
	iommu@lists.linux.dev, Joerg Roedel <joro@8bytes.org>,
	Will Deacon <will@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Gerd Bayer <gbayer@linux.ibm.com>,
	Pierre Morel <pmorel@linux.ibm.com>,
	linux-s390@vger.kernel.org, borntraeger@linux.ibm.com,
	hca@linux.ibm.com, gor@linux.ibm.com,
	gerald.schaefer@linux.ibm.com, agordeev@linux.ibm.com,
	svens@linux.ibm.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/5] iommu/s390: Use RCU to allow concurrent domain_list iteration
Date: Thu, 20 Oct 2022 08:05:20 -0300	[thread overview]
Message-ID: <Y1ErcEe82yjJI+ET@nvidia.com> (raw)
In-Reply-To: <f3551bb461b3ef3cfc1a0c644093816be1835b3f.camel@linux.ibm.com>

On Thu, Oct 20, 2022 at 10:51:10AM +0200, Niklas Schnelle wrote:

> Ok that makes sense thanks for the explanation. So yes my assessment is
> still that in this situation the IOTLB flush is architected to return
> an error that we can ignore. Not the most elegant I admit but at least
> it's simple. Alternatively I guess we could use call_rcu() to do the
> zpci_unregister_ioat() but I'm not sure how to then make sure that a
> subsequent zpci_register_ioat() only happens after that without adding
> too much more logic.

This won't work either as the domain could have been freed before the
call_rcu() happens, the domain needs to be detached synchronously

Jason

  reply	other threads:[~2022-10-20 11:05 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-18 14:51 [PATCH 0/5] iommu/s390: Further improvements Niklas Schnelle
2022-10-18 14:51 ` [PATCH 1/5] iommu/s390: Make attach succeed even if the device is in error state Niklas Schnelle
2022-10-28 15:55   ` Matthew Rosato
2022-10-18 14:51 ` [PATCH 2/5] iommu/s390: Add I/O TLB ops Niklas Schnelle
2022-10-28 16:03   ` Matthew Rosato
2022-10-31 16:11     ` Robin Murphy
2022-11-02 10:51       ` Niklas Schnelle
2022-10-18 14:51 ` [PATCH 3/5] iommu/s390: Use RCU to allow concurrent domain_list iteration Niklas Schnelle
2022-10-18 15:18   ` Jason Gunthorpe
2022-10-19  8:31     ` Niklas Schnelle
2022-10-19 11:53       ` Jason Gunthorpe
2022-10-20  8:51         ` Niklas Schnelle
2022-10-20 11:05           ` Jason Gunthorpe [this message]
2022-10-21 12:08             ` Niklas Schnelle
2022-10-21 13:36               ` Jason Gunthorpe
2022-10-21 15:01                 ` Niklas Schnelle
2022-10-21 15:04                   ` Jason Gunthorpe
2022-10-24 15:22                     ` Niklas Schnelle
2022-10-24 16:26                       ` Jason Gunthorpe
2022-10-27 12:44                         ` Niklas Schnelle
2022-10-27 12:56                           ` Jason Gunthorpe
2022-10-27 13:35                             ` Niklas Schnelle
2022-10-27 14:03                               ` Jason Gunthorpe
2022-10-28  9:29                                 ` Niklas Schnelle
2022-10-28 11:28                                   ` Jason Gunthorpe
2022-10-21 15:05                   ` Niklas Schnelle
2022-10-18 14:51 ` [PATCH 4/5] iommu/s390: Optimize IOMMU table walking Niklas Schnelle
2022-10-18 14:51 ` [PATCH 5/5] s390/pci: use lock-free I/O translation updates Niklas Schnelle

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