From: Jason Gunthorpe jgg@nvidia.com Sent: Friday, February 24, 2023 8:58 AM
On Wed, Feb 22, 2023 at 02:11:39AM +0000, Tian, Kevin wrote:
There was an attempt [1] to fix error unwind in iommu_attach_group(),
by
temporarily set group->domain to NULL before calling set_domain().
Jason, I wonder why this recovering cannot be done in __iommu_group_set_domain() directly, e.g.:
ret = __iommu_group_for_each_dev(group, new_domain, iommu_group_do_attach_device); if (ret) { __iommu_group_for_each_dev(group, group->domain, iommu_group_do_attach_device); return ret; } group->domain = new_domain;
We talked about this already, some times this is not the correct recovery case, eg if we are going to a blocking domain we need to drop all references to the prior domain, not put them back.
Failures are WARN_ON events not error recovery.
OK, I remember that. Then here looks we also need temporarily set group->domain to NULL before calling set_domain() to recover, as [1] does.
Sigh, this is too much.
I made a series to clean up all the domain attach logic so the error handling is all in one place and all the same.
What do you think?
Yeah, that sounds a right cleanup at a glance.