Thread (9 messages) 9 messages, 5 authors, 2012-05-23

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

From: Konrad Rzeszutek Wilk <hidden>
Date: 2012-05-22 18:38:00
Also in: lkml

On Tue, May 22, 2012 at 08:42:10AM -0500, Seth Jennings wrote:
On 05/21/2012 09:19 AM, Seth Jennings wrote:
quoted
On 05/20/2012 09:23 PM, Minchan Kim wrote:
quoted
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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