On 2024/5/8 8:11, Jason Gunthorpe wrote:
On Tue, Apr 30, 2024 at 10:57:06PM +0800, Lu Baolu wrote:diff --git a/drivers/iommu/iommu-priv.h b/drivers/iommu/iommu-priv.h index ae65e0b85d69..1a0450a83bd0 100644 --- a/drivers/iommu/iommu-priv.h +++ b/drivers/iommu/iommu-priv.h @@ -36,6 +36,10 @@ struct iommu_attach_handle { struct device *dev; refcount_t users; }; + /* attach data for IOMMUFD */ + struct { + void *idev; + };We can use a proper type here, just forward declare it. But this sequence in the other patch: + ret = iommu_attach_group(hwpt->domain, idev->igroup->group); + if (ret) { + iommufd_fault_iopf_disable(idev); + return ret; + } + + handle = iommu_attach_handle_get(idev->igroup->group, IOMMU_NO_PASID, 0); + handle->idev = idev; Is why I was imagining the caller would allocate, because now we have the issue that a fault capable domain was installed into the IOMMU before it's handle could be fully setup, so we have a race where a fault could come in right between those things. Then what happens? I suppose we can retry the fault and by the time it comes back the race should resolve. A bit ugly I suppose.
You are right. It makes more sense if the attached data is allocated and managed by the caller. I will go in this direction and update my series. I will also consider other review comments you have given in other places. Best regards, baolu
