migration: new ram_init_bitmaps()

Rearrange the bitmap initialization and the first sync.  Since at it,
make sure the locks are taken/released in correct order (I moved RCU
unlock upper - though it may not affect much).

Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

1 files changed, 30 insertions, 21 deletions

diff --git a/migration/ram.c b/migration/ram.c
index 60f9cfe..1b19a89 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -2110,30 +2110,15 @@ static int ram_state_init(RAMState **rsp)
     return 0;
 }
 
-static int ram_init_all(RAMState **rsp)
+static void ram_list_init_bitmaps(void)
 {
-    if (ram_state_init(rsp)) {
-        return -1;
-    }
-
-    if (xbzrle_init()) {
-        ram_state_cleanup(rsp);
-        return -1;
-    }
-
-    /* For memory_global_dirty_log_start below.  */
-    qemu_mutex_lock_iothread();
-
-    qemu_mutex_lock_ramlist();
-    rcu_read_lock();
+    RAMBlock *block;
+    unsigned long pages;
 
     /* Skip setting bitmap if there is no RAM */
     if (ram_bytes_total()) {
-        RAMBlock *block;
-
         QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
-            unsigned long pages = block->max_length >> TARGET_PAGE_BITS;
-
+            pages = block->max_length >> TARGET_PAGE_BITS;
             block->bmap = bitmap_new(pages);
             bitmap_set(block->bmap, 0, pages);
             if (migrate_postcopy_ram()) {
@@ -2142,12 +2127,36 @@ static int ram_init_all(RAMState **rsp)
             }
         }
     }
+}
+
+static void ram_init_bitmaps(RAMState *rs)
+{
+    /* For memory_global_dirty_log_start below.  */
+    qemu_mutex_lock_iothread();
+    qemu_mutex_lock_ramlist();
+    rcu_read_lock();
 
+    ram_list_init_bitmaps();
     memory_global_dirty_log_start();
-    migration_bitmap_sync(*rsp);
+    migration_bitmap_sync(rs);
+
+    rcu_read_unlock();
     qemu_mutex_unlock_ramlist();
     qemu_mutex_unlock_iothread();
-    rcu_read_unlock();
+}
+
+static int ram_init_all(RAMState **rsp)
+{
+    if (ram_state_init(rsp)) {
+        return -1;
+    }
+
+    if (xbzrle_init()) {
+        ram_state_cleanup(rsp);
+        return -1;
+    }
+
+    ram_init_bitmaps(*rsp);
 
     return 0;
 }