Re: [PATCH 09/14] iommufd: Add iommufd_device_replace()

On 2/27/23 9:58 PM, Jason Gunthorpe wrote:

On Sun, Feb 26, 2023 at 11:01:59AM +0800, Baolu Lu wrote:

...

On 2/25/23 8:27 AM, Jason Gunthorpe wrote:

...

@@ -437,25 +517,77 @@ int iommufd_device_attach(struct iommufd_device *idev, u32 *pt_id) struct iommufd_ioas *ioas = container_of(pt_obj, struct iommufd_ioas, obj);

• rc = iommufd_device_auto_get_domain(idev, ioas, pt_id);
  

• if (rc)
  

• destroy_hwpt = iommufd_device_auto_get_domain(idev, ioas, pt_id,
  

• 					      do_attach);
  

• if (IS_ERR(destroy_hwpt))
  	goto out_put_pt_obj;
  break;
  

  } default:

• rc = -EINVAL;
  

• destroy_hwpt = ERR_PTR(-EINVAL);
  goto out_put_pt_obj;
  

  }
• iommufd_put_object(pt_obj);

• refcount_inc(&idev->obj.users);
• rc = 0;

• /* This destruction has to be after we unlock everything */
• if (destroy_hwpt)

Should this be

if (!IS_ERR_OR_NULL(destroy_hwpt))

?

Never use IS_ERR_OR_NULL ..

Can you please elaborate a bit on this? I can still see a lot of use of it in the tree.

What am I missing? all the flows that could possibly have err_ptr here do goto_out_put_pt_obj ?

Oh yes! You are right. All err_ptr's have gone to an error handling path.

Best regards, baolu