Re: [PATCH] spi: atmel: Fix test unsigned var < 0

[Axel Lin <axel.lin@xxxxxxxxxx>]

2014-03-27 9:13 GMT+08:00 Yang, Wenyou <Wenyou.Yang@xxxxxxxxx>:
>
>> -----Original Message-----
>> From: Axel Lin [mailto:axel.lin@xxxxxxxxxx]
>> Sent: Thursday, March 27, 2014 8:46 AM
>> To: Mark Brown
>> Cc: Yang, Wenyou; linux-spi
>> Subject: Re: [PATCH] spi: atmel: Fix test unsigned var < 0
>>
>> 2014-03-27 0:51 GMT+08:00 Mark Brown <broonie@xxxxxxxxxx>:
>> > On Sat, Mar 22, 2014 at 10:33:29PM +0800, Axel Lin wrote:
>> >> current_remaining_bytes is an unsigned long and cannot be below 0.
>> >
>> >> -     if (xfer->bits_per_word > 8) {
>> >> +
>> >> +     if (xfer->bits_per_word > 8)
>> >>               as->current_remaining_bytes -= 2;
>> >> -             if (as->current_remaining_bytes < 0)
>> >> -                     as->current_remaining_bytes = 0;
>> >> -     } else {
>> >> +     else
>> >>               as->current_remaining_bytes--;
>> >> -     }
>> >
>> > This removes an error check in the case that we set the remaining
>> > bytes to -1.  The length validation the core does should ensure that
>> > never happens but it seems wrong to just ignore that - we should at
>> > least note in the changelog that the analysis has been done.
>> I thought it never happen and there is no bug report for this so it's
>> safe with this patch.
>>
>> >
>> > Are you sure that the best fix isn't to just use an int here?
>> Wenyou,
>>   Any comments for this?
>
> Like Mark said, It seems it is more reasonable using a signed int, instead of unsigned int.
OK. I'm sending a formal patch with your Signed-off-by now.

Regards,
Axel
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