INVALID_BDEV_BLOCK
unsigned long blk_idx = INVALID_BDEV_BLOCK;
if (blk_idx == INVALID_BDEV_BLOCK) {
if (blk_idx == INVALID_BDEV_BLOCK) {
blk_idx = INVALID_BDEV_BLOCK;
if (blk_idx != INVALID_BDEV_BLOCK)
return INVALID_BDEV_BLOCK;