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Date:   Mon, 9 Jan 2023 08:17:07 -0400
From:   Jason Gunthorpe <jgg@nvidia.com>
To:     Baolu Lu <baolu.lu@linux.intel.com>
Cc:     Joerg Roedel <joro@8bytes.org>,
        Christoph Hellwig <hch@infradead.org>,
        Kevin Tian <kevin.tian@intel.com>,
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        Jean-Philippe Brucker <jean-philippe@linaro.org>,
        Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
        Hector Martin <marcan@marcan.st>,
        Sven Peter <sven@svenpeter.dev>,
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        Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
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        Chen-Yu Tsai <wens@csie.org>,
        Thierry Reding <thierry.reding@gmail.com>,
        iommu@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 10/19] iommu: Add set_platform_dma_ops iommu ops
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On Sat, Jan 07, 2023 at 10:48:31AM +0800, Baolu Lu wrote:
> On 1/6/2023 10:26 PM, Jason Gunthorpe wrote:
> > On Fri, Jan 06, 2023 at 02:07:32PM +0800, Baolu Lu wrote:
> > 
> > > Above looks good to me. Thanks! I have updated this part of code like
> > > below:
> > > 
> > > @@ -2177,10 +2188,20 @@ static int __iommu_group_set_domain(struct
> > > iommu_group *group,
> > >           * platform specific behavior.
> > >           */
> > >          if (!new_domain) {
> > > -               if (WARN_ON(!group->domain->ops->detach_dev))
> > > -                       return -EINVAL;
> > > -               __iommu_group_for_each_dev(group, group->domain,
> > > -                                          iommu_group_do_detach_device);
> > > +               struct group_device *grp_dev;
> > > +
> > > +               grp_dev = list_first_entry(&group->devices,
> > > +                                          struct group_device, list);
> > It seems OK - I hope we naturally can't ever get in a situation where
> > a group has disjoint iommu drivers.
> 
> The final code after cleanup looks like below. We will WARN_ON the lack
> of callback in the iommu_group_do_set_platform_dma() helper.

Yeah OK

Jason