[PATCH 2/5] migration: We only need last_stage in two places

[Juan Quintela <quintela@redhat.com>]

And we are passing it all around.  Just add a field to RAMState that
passes it.

Signed-off-by: Juan Quintela <quintela@redhat.com>
---
 migration/ram.c | 41 ++++++++++++++++++-----------------------
 1 file changed, 18 insertions(+), 23 deletions(-)

diff --git a/migration/ram.c b/migration/ram.c
index 57efa67f20..7223b0d8ca 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -325,7 +325,8 @@ struct RAMState {
     uint64_t xbzrle_bytes_prev;
     /* Start using XBZRLE (e.g., after the first round). */
     bool xbzrle_enabled;
-
+    /* Are we on the last stage of migration */
+    bool last_stage;
     /* compression statistics since the beginning of the period */
     /* amount of count that no free thread to compress data */
     uint64_t compress_thread_busy_prev;
@@ -683,11 +684,10 @@ static void xbzrle_cache_zero_page(RAMState *rs, ram_addr_t current_addr)
  * @current_addr: addr of the page
  * @block: block that contains the page we want to send
  * @offset: offset inside the block for the page
- * @last_stage: if we are at the completion stage
  */
 static int save_xbzrle_page(RAMState *rs, uint8_t **current_data,
                             ram_addr_t current_addr, RAMBlock *block,
-                            ram_addr_t offset, bool last_stage)
+                            ram_addr_t offset)
 {
     int encoded_len = 0, bytes_xbzrle;
     uint8_t *prev_cached_page;
@@ -695,7 +695,7 @@ static int save_xbzrle_page(RAMState *rs, uint8_t **current_data,
     if (!cache_is_cached(XBZRLE.cache, current_addr,
                          ram_counters.dirty_sync_count)) {
         xbzrle_counters.cache_miss++;
-        if (!last_stage) {
+        if (!rs->last_stage) {
             if (cache_insert(XBZRLE.cache, current_addr, *current_data,
                              ram_counters.dirty_sync_count) == -1) {
                 return -1;
@@ -734,7 +734,7 @@ static int save_xbzrle_page(RAMState *rs, uint8_t **current_data,
      * Update the cache contents, so that it corresponds to the data
      * sent, in all cases except where we skip the page.
      */
-    if (!last_stage && encoded_len != 0) {
+    if (!rs->last_stage && encoded_len != 0) {
         memcpy(prev_cached_page, XBZRLE.current_buf, TARGET_PAGE_SIZE);
         /*
          * In the case where we couldn't compress, ensure that the caller
@@ -1290,9 +1290,8 @@ static int save_normal_page(RAMState *rs, RAMBlock *block, ram_addr_t offset,
  * @rs: current RAM state
  * @block: block that contains the page we want to send
  * @offset: offset inside the block for the page
- * @last_stage: if we are at the completion stage
  */
-static int ram_save_page(RAMState *rs, PageSearchStatus *pss, bool last_stage)
+static int ram_save_page(RAMState *rs, PageSearchStatus *pss)
 {
     int pages = -1;
     uint8_t *p;
@@ -1307,8 +1306,8 @@ static int ram_save_page(RAMState *rs, PageSearchStatus *pss, bool last_stage)
     XBZRLE_cache_lock();
     if (rs->xbzrle_enabled && !migration_in_postcopy()) {
         pages = save_xbzrle_page(rs, &p, current_addr, block,
-                                 offset, last_stage);
-        if (!last_stage) {
+                                 offset);
+        if (!rs->last_stage) {
             /* Can't send this cached data async, since the cache page
              * might get updated before it gets to the wire
              */
@@ -2129,10 +2128,8 @@ static bool save_compress_page(RAMState *rs, RAMBlock *block, ram_addr_t offset)
  *
  * @rs: current RAM state
  * @pss: data about the page we want to send
- * @last_stage: if we are at the completion stage
  */
-static int ram_save_target_page(RAMState *rs, PageSearchStatus *pss,
-                                bool last_stage)
+static int ram_save_target_page(RAMState *rs, PageSearchStatus *pss)
 {
     RAMBlock *block = pss->block;
     ram_addr_t offset = ((ram_addr_t)pss->page) << TARGET_PAGE_BITS;
@@ -2171,7 +2168,7 @@ static int ram_save_target_page(RAMState *rs, PageSearchStatus *pss,
         return ram_save_multifd_page(rs, block, offset);
     }
 
-    return ram_save_page(rs, pss, last_stage);
+    return ram_save_page(rs, pss);
 }
 
 /**
@@ -2190,10 +2187,8 @@ static int ram_save_target_page(RAMState *rs, PageSearchStatus *pss,
  * @rs: current RAM state
  * @ms: current migration state
  * @pss: data about the page we want to send
- * @last_stage: if we are at the completion stage
  */
-static int ram_save_host_page(RAMState *rs, PageSearchStatus *pss,
-                              bool last_stage)
+static int ram_save_host_page(RAMState *rs, PageSearchStatus *pss)
 {
     int tmppages, pages = 0;
     size_t pagesize_bits =
@@ -2211,7 +2206,7 @@ static int ram_save_host_page(RAMState *rs, PageSearchStatus *pss,
     do {
         /* Check the pages is dirty and if it is send it */
         if (migration_bitmap_clear_dirty(rs, pss->block, pss->page)) {
-            tmppages = ram_save_target_page(rs, pss, last_stage);
+            tmppages = ram_save_target_page(rs, pss);
             if (tmppages < 0) {
                 return tmppages;
             }
@@ -2245,13 +2240,11 @@ static int ram_save_host_page(RAMState *rs, PageSearchStatus *pss,
  * or negative on error
  *
  * @rs: current RAM state
- * @last_stage: if we are at the completion stage
  *
  * On systems where host-page-size > target-page-size it will send all the
  * pages in a host page that are dirty.
  */
-
-static int ram_find_and_save_block(RAMState *rs, bool last_stage)
+static int ram_find_and_save_block(RAMState *rs)
 {
     PageSearchStatus pss;
     int pages = 0;
@@ -2280,7 +2273,7 @@ static int ram_find_and_save_block(RAMState *rs, bool last_stage)
         }
 
         if (found) {
-            pages = ram_save_host_page(rs, &pss, last_stage);
+            pages = ram_save_host_page(rs, &pss);
         }
     } while (!pages && again);
 
@@ -3080,7 +3073,7 @@ static int ram_save_iterate(QEMUFile *f, void *opaque)
                 break;
             }
 
-            pages = ram_find_and_save_block(rs, false);
+            pages = ram_find_and_save_block(rs);
             /* no more pages to sent */
             if (pages == 0) {
                 done = 1;
@@ -3160,6 +3153,8 @@ static int ram_save_complete(QEMUFile *f, void *opaque)
     RAMState *rs = *temp;
     int ret = 0;
 
+    rs->last_stage = !migration_in_colo_state();
+
     WITH_RCU_READ_LOCK_GUARD() {
         if (!migration_in_postcopy()) {
             migration_bitmap_sync_precopy(rs);
@@ -3173,7 +3168,7 @@ static int ram_save_complete(QEMUFile *f, void *opaque)
         while (true) {
             int pages;
 
-            pages = ram_find_and_save_block(rs, !migration_in_colo_state());
+            pages = ram_find_and_save_block(rs);
             /* no more blocks to sent */
             if (pages == 0) {
                 break;
-- 
2.33.1