migration/ram: Merge save_zero_page functions

We don't need to do this in two pieces. One single function makes it
easier to grasp, specially since it removes the indirection on the
return value handling.

Signed-off-by: Fabiano Rosas <farosas@suse.de>

migration/ram.c

@@ -561,7 +561,6 @@ void mig_throttle_counter_reset(void)
 /**
  * xbzrle_cache_zero_page: insert a zero page in the XBZRLE cache
  *
- * @rs: current RAM state
  * @current_addr: address for the zero page
  *
  * Update the xbzrle cache to reflect a page that's been sent as all 0.
@@ -570,7 +569,7 @@ void mig_throttle_counter_reset(void)
  * As a bonus, if the page wasn't in the cache it gets added so that
  * when a small write is made into the 0'd page it gets XBZRLE sent.
  */
-static void xbzrle_cache_zero_page(RAMState *rs, ram_addr_t current_addr)
+static void xbzrle_cache_zero_page(ram_addr_t current_addr)
 {
     /* We don't care if this fails to allocate a new cache page
      * as long as it updated an old one */
@@ -1129,51 +1128,46 @@ void ram_release_page(const char *rbname, uint64_t offset)
     ram_discard_range(rbname, offset, TARGET_PAGE_SIZE);
 }
 
-/**
- * save_zero_page_to_file: send the zero page to the file
- *
- * Returns the size of data written to the file, 0 means the page is not
- * a zero page
- *
- * @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_to_file(PageSearchStatus *pss, QEMUFile *file,
-                                  RAMBlock *block, ram_addr_t offset)
-{
-    uint8_t *p = block->host + offset;
-    int len = 0;
-
-    if (buffer_is_zero(p, TARGET_PAGE_SIZE)) {
-        len += save_page_header(pss, file, block, offset | RAM_SAVE_FLAG_ZERO);
-        qemu_put_byte(file, 0);
-        len += 1;
-        ram_release_page(block->idstr, offset);
-    }
-    return len;
-}
-
 /**
  * save_zero_page: send the zero page to the stream
  *
  * 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, QEMUFile *f, 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, f, block, offset);
+    uint8_t *p = block->host + offset;
+    QEMUFile *file = pss->pss_channel;
+    int len = 0;
 
-    if (len) {
-        stat64_add(&mig_stats.zero_pages, 1);
-        ram_transferred_add(len);
-        return 1;
+    if (!buffer_is_zero(p, TARGET_PAGE_SIZE)) {
+        return 0;
     }
-    return -1;
+
+    len += save_page_header(pss, file, block, offset | RAM_SAVE_FLAG_ZERO);
+    qemu_put_byte(file, 0);
+    len += 1;
+    ram_release_page(block->idstr, offset);
+
+    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 len;
 }
 
 /*
@@ -2141,17 +2135,8 @@ static int ram_save_target_page_legacy(RAMState *rs, PageSearchStatus *pss)
         return 1;
     }
 
-    res = save_zero_page(pss, pss->pss_channel, 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(rs, block->offset + offset);
-            XBZRLE_cache_unlock();
-        }
-        return res;
+    if (save_zero_page(rs, pss, block, offset)) {
+        return 1;
     }
 
     /*