[PATCH v2 1/2] migration: dirty-bitmap: Convert alias map inner members to a struct

[Peter Krempa]

Currently the alias mapping hash stores just strings of the target
objects internally. In further patches we'll be adding another member
which will need to be stored in the map so convert the members to a
struct.

Signed-off-by: Peter Krempa <pkre...@redhat.com>
Reviewed-by: Eric Blake <ebl...@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com>
---

v2:
 - NULL-check in freeing function (Eric)
 - style problems (Vladimir)

 migration/block-dirty-bitmap.c | 43 +++++++++++++++++++++++++++-------
 1 file changed, 35 insertions(+), 8 deletions(-)

diff --git a/migration/block-dirty-bitmap.c b/migration/block-dirty-bitmap.c
index c61d382be8..0169f672df 100644
--- a/migration/block-dirty-bitmap.c
+++ b/migration/block-dirty-bitmap.c
@@ -169,6 +169,22 @@ typedef struct DBMState {

 static DBMState dbm_state;

+typedef struct AliasMapInnerBitmap {
+    char *string;
+} AliasMapInnerBitmap;
+
+static void free_alias_map_inner_bitmap(void *amin_ptr)
+{
+    AliasMapInnerBitmap *amin = amin_ptr;
+
+    if (!amin_ptr) {
+        return;
+    }
+
+    g_free(amin->string);
+    g_free(amin);
+}
+
 /* For hash tables that map node/bitmap names to aliases */
 typedef struct AliasMapInnerNode {
     char *string;
@@ -263,8 +279,8 @@ static GHashTable *construct_alias_map(const 
BitmapMigrationNodeAliasList *bbm,
             node_map_to = bmna->node_name;
         }

-        bitmaps_map = g_hash_table_new_full(g_str_hash, g_str_equal,
-                                            g_free, g_free);
+        bitmaps_map = g_hash_table_new_full(g_str_hash, g_str_equal, g_free,
+                                            free_alias_map_inner_bitmap);

         amin = g_new(AliasMapInnerNode, 1);
         *amin = (AliasMapInnerNode){
@@ -277,6 +293,7 @@ static GHashTable *construct_alias_map(const 
BitmapMigrationNodeAliasList *bbm,
         for (bmbal = bmna->bitmaps; bmbal; bmbal = bmbal->next) {
             const BitmapMigrationBitmapAlias *bmba = bmbal->value;
             const char *bmap_map_from, *bmap_map_to;
+            AliasMapInnerBitmap *bmap_inner;

             if (strlen(bmba->alias) > UINT8_MAX) {
                 error_setg(errp,
@@ -311,8 +328,11 @@ static GHashTable *construct_alias_map(const 
BitmapMigrationNodeAliasList *bbm,
                 }
             }

+            bmap_inner = g_new0(AliasMapInnerBitmap, 1);
+            bmap_inner->string = g_strdup(bmap_map_to);
+
             g_hash_table_insert(bitmaps_map,
-                                g_strdup(bmap_map_from), 
g_strdup(bmap_map_to));
+                                g_strdup(bmap_map_from), bmap_inner);
         }
     }

@@ -538,11 +558,15 @@ static int add_bitmaps_to_list(DBMSaveState *s, 
BlockDriverState *bs,
         }

         if (bitmap_aliases) {
-            bitmap_alias = g_hash_table_lookup(bitmap_aliases, bitmap_name);
-            if (!bitmap_alias) {
+            AliasMapInnerBitmap *bmap_inner;
+
+            bmap_inner = g_hash_table_lookup(bitmap_aliases, bitmap_name);
+            if (!bmap_inner) {
                 /* Skip bitmaps with no alias */
                 continue;
             }
+
+            bitmap_alias = bmap_inner->string;
         } else {
             if (strlen(bitmap_name) > UINT8_MAX) {
                 error_report("Cannot migrate bitmap '%s' on node '%s': "
@@ -1074,14 +1098,17 @@ static int dirty_bitmap_load_header(QEMUFile *f, 
DBMLoadState *s,

         bitmap_name = s->bitmap_alias;
         if (!s->cancelled && bitmap_alias_map) {
-            bitmap_name = g_hash_table_lookup(bitmap_alias_map,
-                                              s->bitmap_alias);
-            if (!bitmap_name) {
+            AliasMapInnerBitmap *bmap_inner;
+
+            bmap_inner = g_hash_table_lookup(bitmap_alias_map, 
s->bitmap_alias);
+            if (!bmap_inner) {
                 error_report("Error: Unknown bitmap alias '%s' on node "
                              "'%s' (alias '%s')", s->bitmap_alias,
                              s->bs->node_name, s->node_alias);
                 cancel_incoming_locked(s);
             }
+
+            bitmap_name = bmap_inner->string;
         }

         if (!s->cancelled) {
-- 
2.29.2