RE: [PATCH v3 12/17] iommufd: Add iommufd_device_replace()

From: Jason Gunthorpe jgg@nvidia.com Sent: Wednesday, March 22, 2023 3:15 AM

• mutex_lock(&idev->igroup->lock);
• if (igroup->hwpt == NULL) {

• rc = -EINVAL;
  

• goto err_unlock;
  

• }
• if (hwpt == igroup->hwpt) {

• mutex_unlock(&idev->igroup->lock);
  

• return NULL;
  

• }

goto err_unlock;

• /* Move the refcounts held by the device_list to the new hwpt */
• refcount_add(num_devices, &hwpt->obj.users);
• if (num_devices > 1)

• WARN_ON(refcount_sub_and_test(num_devices - 1,
  

• 			      &old_hwpt->obj.users));
  

A comment is welcomed to match "caller must destroy old_hwpt".

Otherwise looks good.

Reviewed-by: Kevin Tian kevin.tian@intel.com