linux-kernel - Re: [PATCH v2] mtdchar: fix usage of mtd_ooblayout

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Date:   Tue, 6 Mar 2018 09:26:18 +0100
From:   Boris Brezillon <boris.brezillon@...tlin.com>
To:     欧阳志忠 <oyzhizhong@...il.com>
Cc:     David Woodhouse <dwmw2@...radead.org>,
        Brian Norris <computersforpeace@...il.com>,
        boris.brezillon@...e-electrons.com,
        Marek Vašut <marek.vasut@...il.com>,
        richard@....at, vdavydov.dev@...il.com, cyrille.pitchen@...ev4u.fr,
        linux-mtd@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] mtdchar: fix usage of mtd_ooblayout_ecc()

On Tue, 6 Mar 2018 11:13:25 +0800
欧阳志忠 <oyzhizhong@...il.com> 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.
> 

You still miss the Fixes and Cc-stable tags:

Fixes: c2b78452a9db ("mtd: use mtd_ooblayout_xxx() helpers where appropriate")
Cc: <stable@...r.kernel.org>

Looks good otherwise.

I'm just curious, how did you find the problem? Do you have a userspace
tool that queries the OOB/ECC layout?

> Signed-off-by: OuYang ZhiZhong <oyzhizhong@...il.com>
> ---
>  drivers/mtd/mtdchar.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c
> index de8c902..7d80a8b 100644
> --- a/drivers/mtd/mtdchar.c
> +++ b/drivers/mtd/mtdchar.c
> @@ -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, section++, &oobregion);
>   if (ret < 0) {
>   if (ret != -ERANGE)
>   return ret;
> @@ -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, section++, &oobregion);
>   if (ret < 0) {
>   if (ret != -ERANGE)
>   return ret;



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