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

From: liaoweixiong <liaoweixiong@allwinnertech.com>
To: Boris Brezillon <boris.brezillon@collabora.com>,
	Schrempf Frieder <frieder.schrempf@kontron.de>
Cc: "Vignesh Raghavendra" <vigneshr@ti.com>,
	"Boris Brezillon" <bbrezillon@kernel.org>,
	"Richard Weinberger" <richard@nod.at>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"Marek Vasut" <marek.vasut@gmail.com>,
	"Frieder Schrempf" <frieder.schrempf@exceet.de>,
	"Clément Péron" <peron.clem@gmail.com>,
	"Miquel Raynal" <miquel.raynal@bootlin.com>,
	"linux-mtd@lists.infradead.org" <linux-mtd@lists.infradead.org>,
	"Brian Norris" <computersforpeace@gmail.com>,
	"Chuanhong Guo" <gch981213@gmail.com>,
	"David Woodhouse" <dwmw2@infradead.org>,
	"Peter Pan" <peterpandong@micron.com>
Subject: Re: [PATCH] mtd: spinand: fix error read return value
Date: Thu, 20 Jun 2019 08:40:19 +0800	[thread overview]
Message-ID: <4e8296fb-ff61-9319-99b5-aaa80025ccc6@allwinnertech.com> (raw)
In-Reply-To: <20190619181832.6f467279@collabora.com>

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@kontron.de> wrote:
> 
>> On 19.06.19 15:46, Boris Brezillon wrote:
>>> 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.  
>>
>> 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@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
>>>
>>> ______________________________________________________
>>> Linux MTD discussion mailing list
>>> http://lists.infradead.org/mailman/listinfo/linux-mtd/
>>>  

-- 
liaoweixiong

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