migration: Export ram_load_postcopy()

Will be reused in postcopy fast load thread.

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20220331150857.74406-6-peterx@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

migration/ram.c

@@ -3645,7 +3645,7 @@ int ram_postcopy_incoming_init(MigrationIncomingState *mis)
  *
  * @f: QEMUFile where to send the data
  */
-static int ram_load_postcopy(QEMUFile *f)
+int ram_load_postcopy(QEMUFile *f)
 {
     int flags = 0, ret = 0;
     bool place_needed = false;

migration/ram.h

@@ -61,6 +61,7 @@ void ram_postcopy_send_discard_bitmap(MigrationState *ms);
 /* For incoming postcopy discard */
 int ram_discard_range(const char *block_name, uint64_t start, size_t length);
 int ram_postcopy_incoming_init(MigrationIncomingState *mis);
+int ram_load_postcopy(QEMUFile *f);
 
 void ram_handle_compressed(void *host, uint8_t ch, uint64_t size);