Subject: Re: [PATCH v2] powerpc: support sizes greater than an unsigned long

From: Cristian Stoica <[email-masked]>
Date: Fri, 12 Jun 2015 10:53:25 +0300

On 06/12/2015 12:27 AM, Scott Wood wrote:
> Dropping the upper bits of the size harms the ability to detect error 
> scenarios where unmappably large -- but not power-of-two -- regions 
> are requested to be mapped.
> 
> However, this patch doesn't fix that.  It just postpones the loss of 
> the upper 32 bits until __ioremap_caller() calls get_vm_area_caller().
>
> There's also no error checking at all for the size of ioremap() done 
> during early boot (!slab_is_available()).

Thanks for the explanation. I'll have a another look at the code.

> Don't just blindly turn static analyzer reports into patches -- and 
> why didn't the analyzer complain about the call to 
> get_vm_area_caller() after this patch?

The analysis that lead to this patch was targeted to a specific driver - in hindsight this is probably not the best
approach.

Cristian S.