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/i2c/core.c b/hw/i2c/core.c
index 2c1234c..59068f1 100644
--- a/hw/i2c/core.c
+++ b/hw/i2c/core.c
@@ -41,7 +41,7 @@ static const TypeInfo i2c_bus_info = {
     .instance_size = sizeof(I2CBus),
 };
 
-static void i2c_bus_pre_save(void *opaque)
+static int i2c_bus_pre_save(void *opaque)
 {
     I2CBus *bus = opaque;
 
@@ -53,6 +53,8 @@ static void i2c_bus_pre_save(void *opaque)
             bus->saved_address = I2C_BROADCAST;
         }
     }
+
+    return 0;
 }
 
 static const VMStateDescription vmstate_i2c_bus = {