Now memory_region_register_iommu_notifier() is allowed to fail,
let's handle the returned value in vfio_listener_region_add().

This will allow to remove the error handling (exit) in the
IOMMUs that implement a notify_flag_changed() that sometimes
cannot accept the MAP flag.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
---
 hw/vfio/common.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 3e03c495d8..d57d72cfb9 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -630,9 +630,13 @@ static void vfio_listener_region_add(MemoryListener *listener,
                             section->offset_within_region,
                             int128_get64(llend),
                             iommu_idx);
-        QLIST_INSERT_HEAD(&container->giommu_list, giommu, giommu_next);
 
-        memory_region_register_iommu_notifier(section->mr, &giommu->n);
+        ret = memory_region_register_iommu_notifier(section->mr, &giommu->n);
+        if (ret) {
+            g_free(giommu);
+            goto fail;
+        }
+        QLIST_INSERT_HEAD(&container->giommu_list, giommu, giommu_next);
         memory_region_iommu_replay(giommu->iommu, &giommu->n);
 
         return;
-- 
2.20.1