[PATCH v8 01/29] iommufd: Report unmapped bytes in the error path of iopt_unmap_iova_range

Nicolin Chen
2025-07-05T01:14:01Z

There are callers that read the unmapped bytes even when rc != 0. Thus, do
not forget to report it in the error path too.

Fixes: 8d40205f6093 ("iommufd: Add kAPI toward external drivers for kernel access")
Cc: stable@vger.kernel.org
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
drivers/iommu/iommufd/io_pagetable.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/iommufd/io_pagetable.c b/drivers/iommu/iommufd/io_pagetable.c
index 13d010f19ed1..22fc3a12109f 100644
--- a/drivers/iommu/iommufd/io_pagetable.c
+++ b/drivers/iommu/iommufd/io_pagetable.c
@@ -743,8 +743,10 @@ static int iopt_unmap_iova_range(struct io_pagetable *iopt, unsigned long start,
iommufd_access_notify_unmap(iopt, area_first, length);
/* Something is not responding to unmap requests. */
tries++;
- if (WARN_ON(tries > 100))
- return -EDEADLOCK;
+ if (WARN_ON(tries > 100)) {
+ rc = -EDEADLOCK;
+ goto out_unmapped;
+ }
goto again;
}

@@ -766,6 +768,7 @@ static int iopt_unmap_iova_range(struct io_pagetable *iopt, unsigned long start,
out_unlock_iova:
up_write(&iopt->iova_rwsem);
up_read(&iopt->domains_rwsem);
+out_unmapped:
if (unmapped)
*unmapped = unmapped_bytes;
return rc;
--
2.43.0