From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx187.postini.com [74.125.245.187]) by kanga.kvack.org (Postfix) with SMTP id 8F6DF6B0083 for ; Tue, 22 May 2012 14:46:04 -0400 (EDT) Received: from /spool/local by e7.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 22 May 2012 14:46:03 -0400 Received: from d01relay06.pok.ibm.com (d01relay06.pok.ibm.com [9.56.227.116]) by d01dlp02.pok.ibm.com (Postfix) with ESMTP id BCC436E8062 for ; Tue, 22 May 2012 14:46:00 -0400 (EDT) Received: from d01av04.pok.ibm.com (d01av04.pok.ibm.com [9.56.224.64]) by d01relay06.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q4MIjoAR18743350 for ; Tue, 22 May 2012 14:45:52 -0400 Received: from d01av04.pok.ibm.com (loopback [127.0.0.1]) by d01av04.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id q4MIjmJU016995 for ; Tue, 22 May 2012 14:45:49 -0400 Message-ID: <4FBBDED6.7030600@linux.vnet.ibm.com> Date: Tue, 22 May 2012 13:45:42 -0500 From: Seth Jennings MIME-Version: 1.0 Subject: Re: [PATCH] zsmalloc: use unsigned long instead of void * References: <1337567013-4741-1-git-send-email-minchan@kernel.org> <4FBA4EE2.8050308@linux.vnet.ibm.com> <4FBB97B2.6050408@linux.vnet.ibm.com> <20120522183119.GA24107@phenom.dumpdata.com> In-Reply-To: <20120522183119.GA24107@phenom.dumpdata.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Konrad Rzeszutek Wilk Cc: Minchan Kim , Greg Kroah-Hartman , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , Dan Magenheimer , Nitin Gupta On 05/22/2012 01:31 PM, Konrad Rzeszutek Wilk wrote: > 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 ? Almost. I still need to know what the base is so I can apply the patchset and at least build it before I add my Ack. Thanks, Seth -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org