diff --git a/block.c b/block.c
index b26817495bba015a386520f8eedeacda09c334c7..b8df11d647caeb50964c3babe77d4ab3df1fe306 100644
--- a/block.c
+++ b/block.c
@@ -5575,8 +5575,7 @@ BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs)
         BlockDirtyInfo *info = g_new0(BlockDirtyInfo, 1);
         BlockDirtyInfoList *entry = g_new0(BlockDirtyInfoList, 1);
         info->count = bdrv_get_dirty_count(bs, bm);
-        info->granularity =
-            ((uint32_t) BDRV_SECTOR_SIZE << hbitmap_granularity(bm->bitmap));
+        info->granularity = bdrv_dirty_bitmap_granularity(bm);
         info->has_name = !!bm->name;
         info->name = g_strdup(bm->name);
         entry->value = info;
@@ -5616,6 +5615,11 @@ uint32_t bdrv_get_default_bitmap_granularity(BlockDriverState *bs)
     return granularity;
 }
 
+uint32_t bdrv_dirty_bitmap_granularity(BdrvDirtyBitmap *bitmap)
+{
+    return BDRV_SECTOR_SIZE << hbitmap_granularity(bitmap->bitmap);
+}
+
 void bdrv_dirty_iter_init(BlockDriverState *bs,
                           BdrvDirtyBitmap *bitmap, HBitmapIter *hbi)
 {
diff --git a/include/block/block.h b/include/block/block.h
index 283117ff89744c53ddeadac61f7ff5ef87b0e846..0c0dd6d8b77c4c214e198b0d7210103b3ea62d76 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -460,6 +460,7 @@ void bdrv_dirty_bitmap_make_anon(BlockDriverState *bs, BdrvDirtyBitmap *bitmap);
 void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap);
 BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs);
 uint32_t bdrv_get_default_bitmap_granularity(BlockDriverState *bs);
+uint32_t bdrv_dirty_bitmap_granularity(BdrvDirtyBitmap *bitmap);
 int bdrv_get_dirty(BlockDriverState *bs, BdrvDirtyBitmap *bitmap, int64_t sector);
 void bdrv_set_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap,
                            int64_t cur_sector, int nr_sectors);