Re: [PATCH] mtdchar: fix usage of mtd_ooblayout_ecc()

From: Boris Brezillon
Date: Mon Mar 05 2018 - 10:32:43 EST


Hi OuYang,

On Mon, 5 Mar 2018 22:53:46 +0800
OuYang ZhiZhong <oyzhizhong@xxxxxxxxx> wrote:

> Section was not properly computed. The value of OOB region definition is
> always ECC section 0 information in the OOB area, but we want to get all
> the ECC bytes information, so we should call
> mtd_ooblayout_ecc(mtd, section++, &oobregion) until it returns -ERANGE.

Oops, indeed.

>
> This is fixed by using i instead of section.
>

Fixes: c2b78452a9db ("mtd: use mtd_ooblayout_xxx() helpers where appropriate")
Cc: <stable@xxxxxxxxxxxxxxx>


> Signed-off-by: OuYang ZhiZhong <oyzhizhong@xxxxxxxxx>
> ---
> drivers/mtd/mtdchar.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c
> index de8c902..0cc929e 100644
> --- a/drivers/mtd/mtdchar.c
> +++ b/drivers/mtd/mtdchar.c
> @@ -468,7 +468,7 @@ static int shrink_ecclayout(struct mtd_info *mtd,
> struct nand_ecclayout_user *to)
> {
> struct mtd_oob_region oobregion;
> - int i, section = 0, ret;
> + int i, ret;
>
> if (!mtd || !to)
> return -EINVAL;
> @@ -479,7 +479,7 @@ static int shrink_ecclayout(struct mtd_info *mtd,
> for (i = 0; i < MTD_MAX_ECCPOS_ENTRIES;) {
> u32 eccpos;
>
> - ret = mtd_ooblayout_ecc(mtd, section, &oobregion);
> + ret = mtd_ooblayout_ecc(mtd, i, &oobregion);

Nope, you're not fixing the problem with that: i is encoding the
->eccpos index, not the OOB section. You should really do section++,
either here, or in the for statement.

> if (ret < 0) {
> if (ret != -ERANGE)
> return ret;
> @@ -515,7 +515,7 @@ static int shrink_ecclayout(struct mtd_info *mtd,
> static int get_oobinfo(struct mtd_info *mtd, struct nand_oobinfo *to)
> {
> struct mtd_oob_region oobregion;
> - int i, section = 0, ret;
> + int i, ret;
>
> if (!mtd || !to)
> return -EINVAL;
> @@ -526,7 +526,7 @@ static int get_oobinfo(struct mtd_info *mtd, struct nand_oobinfo *to)
> for (i = 0; i < ARRAY_SIZE(to->eccpos);) {
> u32 eccpos;
>
> - ret = mtd_ooblayout_ecc(mtd, section, &oobregion);
> + ret = mtd_ooblayout_ecc(mtd, i, &oobregion);

Ditto.

> if (ret < 0) {
> if (ret != -ERANGE)
> return ret;

Thanks,

Boris

--
Boris Brezillon, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com