On Wed, Aug 01, 2012 at 12:08:08AM +0800, Axel Lin wrote:
> 於 二，2012-07-31 於 16:41 +0100，Mark Brown 提到：
> > So the above cast probably isn't right... you shouldn't need a double
> > cast here.
> The issue of original warning is: ( I compile the kernel on x86_64 )
> warning: cast to pointer from integer of different size
> What this patch does is:
> cast best_val to uintptr_t, which is an unsigned integer large enough to
> hold a void* pointer.
> And then cast it to (void *).
> Thus I did (void *)(uintptr_t)best_val.
Perhaps we need a temporary variable here. The double cast just looks
too horrible.
2012/8/3 Mark Brown <[email protected]>:
> On Wed, Aug 01, 2012 at 12:08:08AM +0800, Axel Lin wrote:
>> ?? ?G?A2012-07-31 ?? 16:41 +0100?AMark Brown ?????G
>
>> > So the above cast probably isn't right... you shouldn't need a double
>> > cast here.
>
>> The issue of original warning is: ( I compile the kernel on x86_64 )
>> warning: cast to pointer from integer of different size
>
>> What this patch does is:
>> cast best_val to uintptr_t, which is an unsigned integer large enough to
>> hold a void* pointer.
>
>> And then cast it to (void *).
>
>> Thus I did (void *)(uintptr_t)best_val.
>
> Perhaps we need a temporary variable here. The double cast just looks
> too horrible.
Either is ok to me.
But the double case looks better to me because the intention is clear.
It seems uintptr_t is less commonly used in drivers code.
Maybe just use (void *)(unsigned long)best_val is better in readability.
On Mon, Aug 06, 2012 at 12:10:33AM +0800, Axel Lin wrote:
> Either is ok to me.
> But the double case looks better to me because the intention is clear.
> It seems uintptr_t is less commonly used in drivers code.
> Maybe just use (void *)(unsigned long)best_val is better in readability.
Two casts just looks terrible to me to be honest, it'll set off alarm
bells any time I glance at the code just from the visual pattern.