migration: pre_save return int

Modify the pre_save method on VMStateDescription to return an int
rather than void so that it potentially can fail.

Changed zillions of devices to make them return 0; the only
case I've made it return non-0 is hw/intc/s390_flic_kvm.c that already
had an error_report/return case.

Note: If you add an error exit in your pre_save you must emit
an error_report to say why.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20170925112917.21340-2-dgilbert@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/hw/usb/redirect.c b/hw/usb/redirect.c
index 5e42730449..ec174309db 100644
--- a/hw/usb/redirect.c
+++ b/hw/usb/redirect.c
@@ -2111,11 +2111,13 @@ static void usbredir_buffered_bulk_packet(void *priv, uint64_t id,
  * Migration code
  */
 
-static void usbredir_pre_save(void *priv)
+static int usbredir_pre_save(void *priv)
 {
     USBRedirDevice *dev = priv;
 
     usbredir_fill_already_in_flight(dev);
+
+    return 0;
 }
 
 static int usbredir_post_load(void *priv, int version_id)