netdev - Re: [PATCH net] mscan: zero accidentally copied register content

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Message-ID: <4E8D528D.8020607@hartkopp.net>
Date:	Thu, 06 Oct 2011 09:02:37 +0200
From:	Oliver Hartkopp <socketcan@...tkopp.net>
To:	Wolfram Sang <w.sang@...gutronix.de>
CC:	Wolfgang Grandegger <wg@...ndegger.com>,
	Linux Netdev List <netdev@...r.kernel.org>,
	Andre Naujoks <nautsch@...il.com>
Subject: Re: [PATCH net] mscan: zero accidentally copied register content

On 10/05/11 18:10, Oliver Hartkopp wrote:

> On 10/05/11 17:51, Wolfram Sang wrote:

>>> +		/* zero accidentally copied register content at odd DLCs */
>>> +		if (frame->can_dlc & 1)
>>> +			frame->data[frame->can_dlc] = 0;
>>>  	}
>>>  
>>>  	out_8(&regs->canrflg, MSCAN_RXF);
>>
>> Nice catch, but wouldn't it be more elegant to never have an invalid byte
>> in the first place?
>>
>> if (can_dlc & 1)
>> 	*payload = in_be16() & mask;
>>
> 
> 
> Hm, then i would rather think about changing the for() statement and to read
> byte-by-byte instead of the current in_be16() usage with the 16bit access
> drawbacks ...
> 


I think if one would like to rework the 16bit register access (which is used
in the rx path /and/ in the tx path also) this should go via net-next after
some discussion and testing.

IMHO this fix is small and clear and especially not risky. I wonder if
reworking the 16 bit register access is worth the effort?

Regards,
Oliver
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