[Qemu-devel] [PATCH v15 5/9] Change ram_save_block to return -1 if there are no more changes

[Orit Wasserman <owasserm@redhat.com>]

It will return 0 if the page is unmodifed.

Signed-off-by: Orit Wasserman <owasserm@redhat.com>
---
 arch_init.c |   11 +++++++----
 1 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/arch_init.c b/arch_init.c
index 9fd6346..e36899e 100644
--- a/arch_init.c
+++ b/arch_init.c
@@ -188,7 +188,7 @@ static int ram_save_block(QEMUFile *f)
 {
     RAMBlock *block = last_block;
     ram_addr_t offset = last_offset;
-    int bytes_sent = 0;
+    int bytes_sent = -1;
     MemoryRegion *mr;
 
     if (!block)
@@ -349,8 +349,11 @@ int ram_save_live(QEMUFile *f, int stage, void *opaque)
         int bytes_sent;
 
         bytes_sent = ram_save_block(f);
-        bytes_transferred += bytes_sent;
-        if (bytes_sent == 0) { /* no more blocks */
+        /* bytes_sent 0 represent unchanged page,
+           bytes_sent -1 represent no more blocks*/
+        if (bytes_sent > 0) {
+            bytes_transferred += bytes_sent;
+        } else if (bytes_sent == -1) { /* no more blocks */
             break;
         }
         /* we want to check in the 1st loop, just in case it was the 1st time
@@ -387,7 +390,7 @@ int ram_save_live(QEMUFile *f, int stage, void *opaque)
         int bytes_sent;
 
         /* flush all remaining blocks regardless of rate limiting */
-        while ((bytes_sent = ram_save_block(f)) != 0) {
+        while ((bytes_sent = ram_save_block(f)) != -1) {
             bytes_transferred += bytes_sent;
         }
         migration_end();
-- 
1.7.7.6