IDA_SIZE_SHIFT
nr_ptrs = (size + IDA_BLOCK_SIZE - 1) >> IDA_SIZE_SHIFT;
nr_chunks = (PAGE_SIZE << page_order) >> IDA_SIZE_SHIFT;
nr_ptrs = (ib->size + IDA_BLOCK_SIZE - 1) >> IDA_SIZE_SHIFT;
nr_chunks = (PAGE_SIZE << ib->page_order) >> IDA_SIZE_SHIFT;
#define IDA_BLOCK_SIZE (1UL << IDA_SIZE_SHIFT)
cidaw >>= IDA_SIZE_SHIFT;