Re: [PATCH v2] nvmem: check invalid number of bytes in nvmem_{read,write}()

From: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
To: Biju Das <biju.das@bp.renesas.com>
Cc: Simon Horman <horms@verge.net.au>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Chris Paterson <Chris.Paterson2@renesas.com>,
	Alexandre Belloni <alexandre.belloni@bootlin.com>,
	Alessandro Zummo <a.zummo@towertech.it>,
	Fabrizio Castro <fabrizio.castro@bp.renesas.com>,
	"linux-rtc@vger.kernel.org" <linux-rtc@vger.kernel.org>,
	"linux-renesas-soc@vger.kernel.org" 
	<linux-renesas-soc@vger.kernel.org>
Subject: Re: [PATCH v2] nvmem: check invalid number of bytes in nvmem_{read,write}()
Date: Tue, 11 Dec 2018 09:31:10 +0000	[thread overview]
Message-ID: <ca6c023b-e8a2-09c8-6931-99f9d7b70afe@linaro.org> (raw)
In-Reply-To: <OSBPR01MB2103C137219528C37165A317B8A60@OSBPR01MB2103.jpnprd01.prod.outlook.com>

On 11/12/18 08:16, Biju Das wrote:
> Hi Srini,
> 
> Thanks for the feedback.
> 
>> Subject: Re: [PATCH v2] nvmem: check invalid number of bytes in
>> nvmem_{read,write}()
>>
>>
>>
>> On 10/12/18 15:28, Biju Das wrote:
>>> +/* Stop the user from writing */
>>> +if (offset >= nvmem->size)
>>> +return -ENOSPC;
>>> +
>> This should be "return -EFBIG" to make utilities like dd or sh happy.
>>
>> Look at 38b0774c0598c ("nvmem: core: return EFBIG on out-of-range
>> write") for more info.
> 
> return -ENOSPC also make dd or sh happy. Please let me know which is appropriate by the below results. Based on your feedback, If needed, I can send a patch with "return -EFBIG"
> 

Lets stay with -EFBIG for now! given the fact that it was already in the 
old code!

--srini

> With -ENOSPC
> ------------
> dd if=1.bin of=/sys/bus/nvmem/devices/pcf85x63-0/nvmem bs=1 count=2
> dd: writing '/sys/bus/nvmem/devices/pcf85x63-0/nvmem': No space left on device
> 2+0 records in
> 1+0 records out
> 
> echo "1234" > /sys/bus/nvmem/devices/pcf85x63-0/nvmem
> -sh: echo: write error: No space left on device
> 
> with -EFBIG
> ------------
> dd if=1.bin of=/sys/bus/nvmem/devices/pcf85x63-0/nvmem bs=1 count
> dd: writing '/sys/bus/nvmem/devices/pcf85x63-0/nvmem': File too large
> 2+0 records in
> 1+0 records out
> 
> echo "1234" > /sys/bus/nvmem/devices/pcf85x63-0/nvmem
> -sh: echo: write error: File too large
> 
> Regards,
> Biju
> 
> 
> 
> 
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