block migration: Allow compile time disable

Many users now prefer to use drive_mirror over NBD as an
alternative to the older migrate -b option; drive_mirror is
more complex to setup but gives you more options (e.g. only
migrating some of the disks if some of them are shared).

Allow the large chunk of block migration code to be compiled
out for those who don't use it.

Based on a downstream-patch we've had for a while by Jeff Cody.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>

--

- When compiled out, allow seting block only with false value (eric)

1 files changed, 23 insertions, 1 deletions

diff --git a/include/migration/block.h b/include/migration/block.h
index 5225af9d2b..28cff53a23 100644
--- a/include/migration/block.h
+++ b/include/migration/block.h
@@ -14,12 +14,34 @@
 #ifndef MIGRATION_BLOCK_H
 #define MIGRATION_BLOCK_H
 
+#ifdef CONFIG_LIVE_BLOCK_MIGRATION
 void blk_mig_init(void);
 int blk_mig_active(void);
 uint64_t blk_mig_bytes_transferred(void);
 uint64_t blk_mig_bytes_remaining(void);
 uint64_t blk_mig_bytes_total(void);
 
-void migrate_set_block_enabled(bool value, Error **errp);
+#else
+static inline void blk_mig_init(void) { }
+static inline int blk_mig_active(void)
+{
+    return false;
+}
+static inline uint64_t blk_mig_bytes_transferred(void)
+{
+    return 0;
+}
+
+static inline uint64_t blk_mig_bytes_remaining(void)
+{
+    return 0;
+}
 
+static inline uint64_t blk_mig_bytes_total(void)
+{
+    return 0;
+}
+#endif /* CONFIG_LIVE_BLOCK_MIGRATION */
+
+void migrate_set_block_enabled(bool value, Error **errp);
 #endif /* MIGRATION_BLOCK_H */