Re: [PATCH] zsmalloc: use unsigned long instead of void *

From: Konrad Rzeszutek Wilk
Date: Tue May 22 2012 - 14:37:59 EST


On Tue, May 22, 2012 at 08:42:10AM -0500, Seth Jennings wrote:
> On 05/21/2012 09:19 AM, Seth Jennings wrote:
>
> > On 05/20/2012 09:23 PM, Minchan Kim wrote:
> >
> >> We should use unsigned long as handle instead of void * to avoid any
> >> confusion. Without this, users may just treat zs_malloc return value as
> >> a pointer and try to deference it.
> >
> >
> > I wouldn't have agreed with you about the need for this change as people
> > should understand a void * to be the address of some data with unknown
> > structure.
> >
> > However, I recently discussed with Dan regarding his RAMster project
> > where he assumed that the void * would be an address, and as such,
> > 4-byte aligned. So he has masked two bits into the two LSBs of the
> > handle for RAMster, which doesn't work with zsmalloc since the handle is
> > not an address.
> >
> > So really we do need to convey as explicitly as possible to the user
> > that the handle is an _opaque_ value about which no assumption can be made.
>
>
> Wasn't really clear here. All that to say, I think we do need this patch.

That sounds like an Acked-by ?

>
> Thanks,
> Seth
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