return 0;
if (ofs > mtd->size) return -EINVAL;  return onenand_block_checkbad(mtd, ofs, 1, 0);
static int onenand_block_isbad(struct mtd_info *mtd, loff_t ofs){	/*	 * TODO 	 * 1. Bad block table (BBT)	 *   -> using NAND BBT to support JFFS2	 * 2. Bad block management (BBM)	 *   -> bad block replace scheme	 *	 * Currently we do nothing	 */	return 0;}