iommufd: Do not add the same hwpt to the ioas->hwpt_list twice

The hwpt is added to the hwpt_list only during its creation, it is never
added again. This hunk is some missed leftover from rework. Adding it
twice will corrupt the linked list in some cases.

It effects HWPT specific attachment, which is something the test suite
cannot cover until we can create a legitimate struct device with a
non-system iommu "driver" (ie we need the bus removed from the iommu code)

Cc: stable@vger.kernel.org
Fixes: e8d57210035b ("iommufd: Add kAPI toward external drivers for physical devices")
Link: https://lore.kernel.org/r/1-v1-4336b5cb2fe4+1d7-iommufd_hwpt_jgg@nvidia.com
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reported-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index 9f3b9674d72e81adea762147535f928766058ac9..a0c66f47a65ada7639fb9c0bc6e6dffecd32102f 100644 (file)
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -344,10 +344,6 @@ int iommufd_device_attach(struct iommufd_device *idev, u32 *pt_id)
                rc = iommufd_device_do_attach(idev, hwpt);
                if (rc)
                        goto out_put_pt_obj;
-
-               mutex_lock(&hwpt->ioas->mutex);
-               list_add_tail(&hwpt->hwpt_item, &hwpt->ioas->hwpt_list);
-               mutex_unlock(&hwpt->ioas->mutex);
                break;
        }
        case IOMMUFD_OBJ_IOAS: {