[PATCH RESEND 5/7] migration/ram: Move xbzrle zero page handling into save_zero_page

[Fabiano Rosas <farosas@suse.de>]

It makes a bit more sense to have the zero page handling of xbzrle
right where we save the zero page.

Also invert the exit condition to remove one level of indentation
which makes the next patch easier to grasp.

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
---
 migration/ram.c | 35 ++++++++++++++++++++---------------
 1 file changed, 20 insertions(+), 15 deletions(-)

diff --git a/migration/ram.c b/migration/ram.c
index c8474f6fd8..1177563523 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -1167,21 +1167,34 @@ static int save_zero_page_to_file(PageSearchStatus *pss, RAMBlock *block,
  *
  * Returns the number of pages written.
  *
+ * @rs: current RAM state
  * @pss: current PSS channel
  * @block: block that contains the page we want to send
  * @offset: offset inside the block for the page
  */
-static int save_zero_page(PageSearchStatus *pss, RAMBlock *block,
+static int save_zero_page(RAMState *rs, PageSearchStatus *pss, RAMBlock *block,
                           ram_addr_t offset)
 {
     int len = save_zero_page_to_file(pss, block, offset);
 
-    if (len) {
-        stat64_add(&mig_stats.zero_pages, 1);
-        ram_transferred_add(len);
-        return 1;
+    if (!len) {
+        return -1;
     }
-    return -1;
+
+    stat64_add(&mig_stats.zero_pages, 1);
+    ram_transferred_add(len);
+
+    /*
+     * Must let xbzrle know, otherwise a previous (now 0'd) cached
+     * page would be stale.
+     */
+    if (rs->xbzrle_started) {
+        XBZRLE_cache_lock();
+        xbzrle_cache_zero_page(block->offset + offset);
+        XBZRLE_cache_unlock();
+    }
+
+    return 1;
 }
 
 /*
@@ -2137,16 +2150,8 @@ static int ram_save_target_page_legacy(RAMState *rs, PageSearchStatus *pss)
         return 1;
     }
 
-    res = save_zero_page(pss, block, offset);
+    res = save_zero_page(rs, pss, block, offset);
     if (res > 0) {
-        /* Must let xbzrle know, otherwise a previous (now 0'd) cached
-         * page would be stale
-         */
-        if (rs->xbzrle_started) {
-            XBZRLE_cache_lock();
-            xbzrle_cache_zero_page(block->offset + offset);
-            XBZRLE_cache_unlock();
-        }
         return res;
     }
 
-- 
2.35.3