virtio_net_handle_migration_primary() returns early when it can't
ensure n->primary_dev is non-null.  Checking it again right after that
early return is redundant.  Drop.

If n->primary_dev is null on entering failover_replug_primary(), @pdev
will become null, and pdev->partially_hotplugged will crash.  Checking
n->primary_dev later is useless.  It can't actually be null, because
its caller virtio_net_handle_migration_primary() ensures it isn't.
Drop the useless check.

Cc: Jens Freimann <jfreimann@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 hw/net/virtio-net.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 3c31471026..87088ba374 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -2810,11 +2810,6 @@ static bool failover_replug_primary(VirtIONet *n, Error **errp)
             goto out;
         }
     }
-    if (!n->primary_dev) {
-            error_setg(errp, "virtio_net: couldn't find primary device");
-            goto out;
-    }
-
     n->primary_bus = n->primary_dev->parent_bus;
     if (!n->primary_bus) {
         error_setg(errp, "virtio_net: couldn't find primary bus");
@@ -2849,8 +2844,7 @@ static void virtio_net_handle_migration_primary(VirtIONet *n,
         }
     }
 
-    if (migration_in_setup(s) && !should_be_hidden &&
-        n->primary_dev) {
+    if (migration_in_setup(s) && !should_be_hidden) {
         if (failover_unplug_primary(n)) {
             vmstate_unregister(n->primary_dev, qdev_get_vmsd(n->primary_dev),
                     n->primary_dev);
-- 
2.21.0

On Sat, Nov 30, 2019 at 08:42:20PM +0100, Markus Armbruster wrote:
>virtio_net_handle_migration_primary() returns early when it can't
>ensure n->primary_dev is non-null.  Checking it again right after that
>early return is redundant.  Drop.
>
>If n->primary_dev is null on entering failover_replug_primary(), @pdev
>will become null, and pdev->partially_hotplugged will crash.  Checking
>n->primary_dev later is useless.  It can't actually be null, because
>its caller virtio_net_handle_migration_primary() ensures it isn't.
>Drop the useless check.
>
>Cc: Jens Freimann <jfreimann@redhat.com>
>Cc: Michael S. Tsirkin <mst@redhat.com>
>Signed-off-by: Markus Armbruster <armbru@redhat.com>
>---
> hw/net/virtio-net.c | 8 +-------
> 1 file changed, 1 insertion(+), 7 deletions(-)
>

Thanks Markus!

Reviewed-by: Jens Freimann <jfreimann@redhat.com>

regards
Jens