Re: [PATCH v6 05/10] iommufd: Derive iommufd_hwpt_paging from iommufd_hw_pagetable

On Tue, Oct 24, 2023 at 08:06:04AM -0700, Yi Liu wrote:

static int iommufd_group_do_replace_paging(struct iommufd_group *igroup,

• 			   struct iommufd_hw_pagetable *hwpt)
  

• 			   struct iommufd_hwpt_paging *hwpt_paging)
  

{ struct iommufd_hw_pagetable *old_hwpt = igroup->hwpt; struct iommufd_device *cur; @@ -441,22 +447,23 @@ static int iommufd_group_do_replace_paging(struct iommufd_group *igroup, lockdep_assert_held(&igroup->lock);

• if (hwpt_is_paging(old_hwpt) && hwpt->ioas != old_hwpt->ioas) {

• if (hwpt_is_paging(old_hwpt) &&

•    hwpt_paging->ioas != to_hwpt_paging(old_hwpt)->ioas) {
  

  list_for_each_entry(cur, &igroup->device_list, group_item) { rc = iopt_table_enforce_dev_resv_regions(

• 		&hwpt->ioas->iopt, cur->dev, NULL);
  

• 		&hwpt_paging->ioas->iopt, cur->dev, NULL);
  if (rc)
  	goto err_unresv;
  

  } }

• rc = iommufd_group_setup_msi(igroup, hwpt);

• rc = iommufd_group_setup_msi(igroup, hwpt_paging); if (rc) goto err_unresv; return 0;

err_unresv:

• iommufd_group_remove_reserved_iova(igroup, hwpt);

• iommufd_group_remove_reserved_iova(igroup, hwpt_paging); return rc;

} @@ -482,7 +489,8 @@ iommufd_device_do_replace(struct iommufd_device *idev, } if (hwpt_is_paging(hwpt)) {

• rc = iommufd_group_do_replace_paging(igroup, hwpt);
  

• rc = iommufd_group_do_replace_paging(igroup,
  

• 				     to_hwpt_paging(hwpt));
  

  if (rc) goto err_unlock; }

@@ -493,8 +501,10 @@ iommufd_device_do_replace(struct iommufd_device *idev, old_hwpt = igroup->hwpt; if (hwpt_is_paging(old_hwpt) &&

•    (!hwpt_is_paging(hwpt) || hwpt->ioas != old_hwpt->ioas))
  

• iommufd_group_remove_reserved_iova(igroup, old_hwpt);
  

•    (!hwpt_is_paging(hwpt) ||
  

•     to_hwpt_paging(hwpt)->ioas != to_hwpt_paging(old_hwpt)->ioas))
  

• iommufd_group_remove_reserved_iova(igroup,
  

• 				   to_hwpt_paging(old_hwpt));
  

igroup->hwpt = hwpt; @@ -513,7 +523,8 @@ iommufd_device_do_replace(struct iommufd_device *idev, return old_hwpt; err_unresv: if (hwpt_is_paging(hwpt))

• iommufd_group_remove_reserved_iova(igroup, hwpt);
  

• iommufd_group_remove_reserved_iova(igroup,
  

• 				   to_hwpt_paging(old_hwpt));
  

This gets a compiler warning:

../drivers/iommu/iommufd/device.c:527:25: warning: variable 'old_hwpt' is uninitialized when used here [-Wuninitialized] to_hwpt_paging(old_hwpt)); ^~~~~~~~ ../drivers/iommu/iommufd/device.c:475:39: note: initialize the variable 'old_hwpt' to silence this warning struct iommufd_hw_pagetable *old_hwpt; ^ = NULL

I fixed it with:

--- a/drivers/iommu/iommufd/device.c +++ b/drivers/iommu/iommufd/device.c @@ -488,6 +488,7 @@ iommufd_device_do_replace(struct iommufd_device *idev, return NULL; }

+ old_hwpt = igroup->hwpt; if (hwpt_is_paging(hwpt)) { rc = iommufd_group_do_replace_paging(igroup, to_hwpt_paging(hwpt)); @@ -499,7 +500,6 @@ iommufd_device_do_replace(struct iommufd_device *idev, if (rc) goto err_unresv;

- old_hwpt = igroup->hwpt; if (hwpt_is_paging(old_hwpt) && (!hwpt_is_paging(hwpt) || to_hwpt_paging(hwpt)->ioas != to_hwpt_paging(old_hwpt)->ioas))

Jason