RE: [PATCH iommufd] iommufd: Make vfio_compat's unmap succeed if the range is already empty

From: Jason Gunthorpe jgg@nvidia.com Sent: Wednesday, November 5, 2025 2:12 AM

sorry coming to this late, but why do we leave inconsistent behavior between unmapping all vs. unmapping a range:

int iopt_unmap_all(struct io_pagetable *iopt, unsigned long *unmapped) {

• int rc;
• rc = iopt_unmap_iova_range(iopt, 0, ULONG_MAX, unmapped); /* If the IOVAs are empty then unmap all succeeds */
• if (rc == -ENOENT)

• return 0;
  

• return rc;

• return iopt_unmap_iova_range(iopt, 0, ULONG_MAX, unmapped);

}

here empty IOVAs succeeds, while...

@@ -367,6 +367,10 @@ int iommufd_ioas_unmap(struct iommufd_ucmd *ucmd) &unmapped); if (rc) goto out_put;

• if (!unmapped) {
  

• 	rc = -ENOENT;
  

• 	goto out_put;
  

• }
  

  }

...here it's a failure.

from uAPI p.o.v. better the two scenarios are consistent?