Re: [PATCH v3 12/15] iommufd: Add kAPI toward external drivers for physical devices

On 2022/10/26 2:12, Jason Gunthorpe wrote:

+/*

• • When automatically managing the domains we search for a compatible domain in
• • the iopt and if one is found use it, otherwise create a new domain.
• • Automatic domain selection will never pick a manually created domain.
• */

+static int iommufd_device_auto_get_domain(struct iommufd_device *idev,

• 			  struct iommufd_ioas *ioas,
  

• 			  unsigned int flags)
  

+{

• struct iommufd_hw_pagetable *hwpt;
• int rc;
• /*

• * There is no differentiation when domains are allocated, so any domain
  

• * that is willing to attach to the device is interchangeable with any
  

• * other.
  

• */
  

• mutex_lock(&ioas->mutex);
• list_for_each_entry(hwpt, &ioas->hwpt_list, hwpt_item) {

• if (!hwpt->auto_domain ||
  

•     !refcount_inc_not_zero(&hwpt->obj.users))
  

• 	continue;
  

• rc = iommufd_device_do_attach(idev, hwpt, flags);
  

• refcount_dec(&hwpt->obj.users);
  

• if (rc) {
  

• 	/*
  

• 	 * FIXME: Requires the series to return EINVAL for
  

• 	 * incompatible domain attaches.
  

• 	 */
  

• 	if (rc == -EINVAL)
  

• 		continue;
  

• 	goto out_unlock;
  

• }
  

• goto out_unlock;
  

Can the above code be simplified as:

if (rc == -EINVAL) continue; goto out_unlock; ?

• }
• hwpt = iommufd_hw_pagetable_alloc(idev->ictx, ioas, idev->dev);
• if (IS_ERR(hwpt)) {

• rc = PTR_ERR(hwpt);
  

• goto out_unlock;
  

• }
• hwpt->auto_domain = true;
• rc = iommufd_device_do_attach(idev, hwpt, flags);
• if (rc)

• goto out_abort;
  

• list_add_tail(&hwpt->hwpt_item, &ioas->hwpt_list);
• mutex_unlock(&ioas->mutex);
• iommufd_object_finalize(idev->ictx, &hwpt->obj);
• return 0;

+out_abort:

• iommufd_object_abort_and_destroy(idev->ictx, &hwpt->obj);

+out_unlock:

• mutex_unlock(&ioas->mutex);
• return rc;

+}

Best regards, baolu