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Date:   Wed, 19 Jun 2019 15:46:11 +0200
From:   Boris Brezillon <boris.brezillon@collabora.com>
To:     liaoweixiong <liaoweixiong@allwinnertech.com>
Cc:     Miquel Raynal <miquel.raynal@bootlin.com>,
        Richard Weinberger <richard@nod.at>,
        David Woodhouse <dwmw2@infradead.org>,
        Brian Norris <computersforpeace@gmail.com>,
        Marek Vasut <marek.vasut@gmail.com>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        Boris Brezillon <bbrezillon@kernel.org>,
        Frieder Schrempf <frieder.schrempf@exceet.de>,
        Peter Pan <peterpandong@micron.com>,
        =?UTF-8?B?Q2zDqW1lbnQgUMOpcm9u?= <peron.clem@gmail.com>,
        Chuanhong Guo <gch981213@gmail.com>,
        linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mtd: spinand: fix error read return value
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Hi liaoweixiong,

On Wed, 19 Jun 2019 21:13:24 +0800
liaoweixiong <liaoweixiong@allwinnertech.com> wrote:

> In function spinand_mtd_read, if the last page to read occurs bitflip,
> this function will return error value because veriable ret not equal to 0.

Actually, that's exactly what the MTD core expects (see [1]), so you're
the one introducing a regression here.

Regards,

Boris

> 
> Signed-off-by: liaoweixiong <liaoweixiong@allwinnertech.com>
> ---
>  drivers/mtd/nand/spi/core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/mtd/nand/spi/core.c b/drivers/mtd/nand/spi/core.c
> index 556bfdb..6b9388d 100644
> --- a/drivers/mtd/nand/spi/core.c
> +++ b/drivers/mtd/nand/spi/core.c
> @@ -511,12 +511,12 @@ static int spinand_mtd_read(struct mtd_info *mtd, loff_t from,
>  		if (ret == -EBADMSG) {
>  			ecc_failed = true;
>  			mtd->ecc_stats.failed++;
> -			ret = 0;
>  		} else {
>  			mtd->ecc_stats.corrected += ret;
>  			max_bitflips = max_t(unsigned int, max_bitflips, ret);
>  		}
>  
> +		ret = 0;
>  		ops->retlen += iter.req.datalen;
>  		ops->oobretlen += iter.req.ooblen;
>  	}

[1]https://elixir.bootlin.com/linux/latest/source/drivers/mtd/mtdcore.c#L1209