From: Brian Norris Date: Fri, 22 Jun 2012 23:35:39 +0000 (-0700) Subject: mtd: check for max_bitflips in mtd_read_oob() X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=e47f68587b8255410e79166cbdecae290ca8a84e;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git mtd: check for max_bitflips in mtd_read_oob() mtd_read_oob() has some unexpected similarities to mtd_read(). For instance, when ops->datbuf != NULL, nand_base.c might return max_bitflips; however, when ops->datbuf == NULL, nand_base's code potentially could return -EUCLEAN (no in-tree drivers do this yet). In any case where the driver might return max_bitflips, we should translate this into an appropriate return code using the bitflip_threshold. Essentially, mtd_read_oob() duplicates the logic from mtd_read(). This prevents users of mtd_read_oob() from receiving a positive return value (i.e., from max_bitflips) and interpreting it as an unknown error. Artem: amend comments. Signed-off-by: Brian Norris Reviewed-by: Mike Dunn Reviewed-by: Shmulik Ladkani Signed-off-by: Artem Bityutskiy Signed-off-by: David Woodhouse --- diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c index fcfce24f87d1..ec794a72975d 100644 --- a/drivers/mtd/mtdcore.c +++ b/drivers/mtd/mtdcore.c @@ -860,10 +860,22 @@ EXPORT_SYMBOL_GPL(mtd_panic_write); int mtd_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops) { + int ret_code; ops->retlen = ops->oobretlen = 0; if (!mtd->_read_oob) return -EOPNOTSUPP; - return mtd->_read_oob(mtd, from, ops); + /* + * In cases where ops->datbuf != NULL, mtd->_read_oob() has semantics + * similar to mtd->_read(), returning a non-negative integer + * representing max bitflips. In other cases, mtd->_read_oob() may + * return -EUCLEAN. In all cases, perform similar logic to mtd_read(). + */ + ret_code = mtd->_read_oob(mtd, from, ops); + if (unlikely(ret_code < 0)) + return ret_code; + if (mtd->ecc_strength == 0) + return 0; /* device lacks ecc */ + return ret_code >= mtd->bitflip_threshold ? -EUCLEAN : 0; } EXPORT_SYMBOL_GPL(mtd_read_oob);