block/dirty-bitmap: add bdrv_dirty_bitmap_next()

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-id: 20170628120530.31251-19-vsementsov@virtuozzo.com
Signed-off-by: Max Reitz <mreitz@redhat.com>

block/dirty-bitmap.c

@@ -718,3 +718,10 @@ bool bdrv_has_changed_persistent_bitmaps(BlockDriverState *bs)
 
     return false;
 }
+
+BdrvDirtyBitmap *bdrv_dirty_bitmap_next(BlockDriverState *bs,
+                                        BdrvDirtyBitmap *bitmap)
+{
+    return bitmap == NULL ? QLIST_FIRST(&bs->dirty_bitmaps) :
+                            QLIST_NEXT(bitmap, list);
+}

include/block/dirty-bitmap.h

@@ -95,5 +95,7 @@ bool bdrv_has_readonly_bitmaps(BlockDriverState *bs);
 bool bdrv_dirty_bitmap_get_autoload(const BdrvDirtyBitmap *bitmap);
 bool bdrv_dirty_bitmap_get_persistance(BdrvDirtyBitmap *bitmap);
 bool bdrv_has_changed_persistent_bitmaps(BlockDriverState *bs);
+BdrvDirtyBitmap *bdrv_dirty_bitmap_next(BlockDriverState *bs,
+                                        BdrvDirtyBitmap *bitmap);
 
 #endif