[PULL 2/3] vfio: don't ignore return value of migrate_add_blocker

[Alex Williamson <alex.williamson@redhat.com>]

From: Jens Freimann <jfreimann@redhat.com>

When an error occurs in migrate_add_blocker() it sets a
negative return value and uses error pointer we pass in.
Instead of just looking at the error pointer check for a negative return
value and avoid a coverity error because the return value is
set but never used. This fixes CID 1407219.

Reported-by: Coverity (CID 1407219)
Fixes: f045a0104c8c ("vfio: unplug failover primary device before migration")
Signed-off-by: Jens Freimann <jfreimann@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
 hw/vfio/pci.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 9c165995df32..0c55883bba77 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -2737,7 +2737,7 @@ static void vfio_realize(PCIDevice *pdev, Error **errp)
         error_setg(&vdev->migration_blocker,
                 "VFIO device doesn't support migration");
         ret = migrate_add_blocker(vdev->migration_blocker, &err);
-        if (err) {
+        if (ret) {
             error_propagate(errp, err);
             error_free(vdev->migration_blocker);
             vdev->migration_blocker = NULL;