[PATCH v3 1/4] net/macb: fix truncate warnings

Joachim Eastwood manabian at gmail.com
Tue Oct 23 13:20:26 EDT 2012


On Tue, Oct 23, 2012 at 2:00 PM, Lothar Waßmann <LW at karo-electronics.de> wrote:
> Hi,
>
> David Miller writes:
>> From: "David Laight" <David.Laight at ACULAB.COM>
>> Date: Tue, 23 Oct 2012 09:21:11 +0100
>>
>> >> When building macb on x86_64 the following warnings show up:
>> >>   drivers/net/ethernet/cadence/macb.c: In function macb_interrupt:
>> >>   drivers/net/ethernet/cadence/macb.c:556:4: warning: large integer implicitly truncated to unsigned type [-Woverflow]
>> > ...
>> >> -                  macb_writel(bp, IDR, ~0UL);
>> >> +                  macb_writel(bp, IDR, -1);
>> >
>> > Seems wrong to fix an error with an unsigned value
>> > by using -1.
>>
>> -1 is equally an unsigned value of all 1's and completely legitimate.
>> The correction being made here is one of size not signedness.
>>
> You could use '~0' (without the 'UL').

The reason for choosing '-1', as noted in patch description, is that
it already appears in a couple of other places in the driver. So I
though it would nice to be consistent.

regards
Joachim Eastwood



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