linux-kernel - Re: [PATCH] mtd: spinand: fix error read return value

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Date:   Thu, 20 Jun 2019 08:40:19 +0800
From:   liaoweixiong <liaoweixiong@...winnertech.com>
To:     Boris Brezillon <boris.brezillon@...labora.com>,
        Schrempf Frieder <frieder.schrempf@...tron.de>
Cc:     Vignesh Raghavendra <vigneshr@...com>,
        Boris Brezillon <bbrezillon@...nel.org>,
        Richard Weinberger <richard@....at>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Chuanhong Guo <gch981213@...il.com>,
        Marek Vasut <marek.vasut@...il.com>,
        Frieder Schrempf <frieder.schrempf@...eet.de>,
        Clément Péron <peron.clem@...il.com>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        "linux-mtd@...ts.infradead.org" <linux-mtd@...ts.infradead.org>,
        Brian Norris <computersforpeace@...il.com>,
        David Woodhouse <dwmw2@...radead.org>,
        Peter Pan <peterpandong@...ron.com>
Subject: Re: [PATCH] mtd: spinand: fix error read return value

hi Boris Brezillon,

Sure, i will adjust the commit message and send again right now.

On 2019/6/20 AM12:18, Boris Brezillon wrote:
> On Wed, 19 Jun 2019 14:02:14 +0000
> Schrempf Frieder <frieder.schrempf@...tron.de> wrote:
> 
>> On 19.06.19 15:46, Boris Brezillon wrote:
>>> Hi liaoweixiong,
>>>
>>> On Wed, 19 Jun 2019 21:13:24 +0800
>>> liaoweixiong <liaoweixiong@...winnertech.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.  
>>
>> To me it looks like the patch description is somewhat incorrect, but the 
>> fix itself looks okay, unless I'm getting it wrong.
>>
>> In case of the last page containing bitflips (ret > 0), 
>> spinand_mtd_read() will return that number of bitflips for the last 
>> page. But to me it looks like it should instead return max_bitflips like 
>> it does when the last page read returns with 0.
> 
> Oh, you're right. liaoweixiong, can you adjust the commit message
> accordingly?
> 
>>
>>>>
>>>> Signed-off-by: liaoweixiong <liaoweixiong@...winnertech.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
>>>
>>> ______________________________________________________
>>> Linux MTD discussion mailing list
>>> http://lists.infradead.org/mailman/listinfo/linux-mtd/
>>>  

-- 
liaoweixiong

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