From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e23smtp03.au.ibm.com ([202.81.31.145]:60370 "EHLO e23smtp03.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752963AbaFYH4x (ORCPT ); Wed, 25 Jun 2014 03:56:53 -0400 Received: from /spool/local by e23smtp03.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 25 Jun 2014 17:56:49 +1000 Received: from d23relay05.au.ibm.com (d23relay05.au.ibm.com [9.190.235.152]) by d23dlp02.au.ibm.com (Postfix) with ESMTP id E73D32BB0040 for ; Wed, 25 Jun 2014 17:56:45 +1000 (EST) Received: from d23av04.au.ibm.com (d23av04.au.ibm.com [9.190.235.139]) by d23relay05.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id s5P7YRnC11206944 for ; Wed, 25 Jun 2014 17:34:27 +1000 Received: from d23av04.au.ibm.com (localhost [127.0.0.1]) by d23av04.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s5P7uitK011270 for ; Wed, 25 Jun 2014 17:56:45 +1000 Message-ID: <1403682997.4587.208.camel@pasglop> Subject: Re: [RFC PATCH V3 06/17] ppc/pnv: allocate pe->iommu_table dynamically From: Benjamin Herrenschmidt To: Alexey Kardashevskiy Cc: Wei Yang , linuxppc-dev@lists.ozlabs.org, bhelgaas@google.com, linux-pci@vger.kernel.org, gwshan@linux.vnet.ibm.com, yan@linux.vnet.ibm.com, qiudayu@linux.vnet.ibm.com Date: Wed, 25 Jun 2014 17:56:37 +1000 In-Reply-To: <53AA7F30.40504@ozlabs.ru> References: <1402365399-5121-1-git-send-email-weiyang@linux.vnet.ibm.com> <1402365399-5121-7-git-send-email-weiyang@linux.vnet.ibm.com> <53A94DA8.6020206@ozlabs.ru> <20140625011211.GA5785@richard> <53AA4C32.7060004@ozlabs.ru> <20140625052758.GA8873@richard> <53AA7F30.40504@ozlabs.ru> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Sender: linux-pci-owner@vger.kernel.org List-ID: On Wed, 2014-06-25 at 17:50 +1000, Alexey Kardashevskiy wrote: > > Yes, iommu_talbe's life time equals to PE lifetime, so when releasing a PE we > > need to release the iommu table. Currently, there is one function to release > > the iommu table, iommu_free_table() which takes a pointer of the iommu_table > > and release it. > > > > If the iommu table in PE is just a part of PE, it will have some problem to > > release it with iommu_free_table(). That's why I make it a pointer in PE > > structure. > > So you are saying that you want to release PE by one kfree() and release > iommu_table by another kfree (embedded into iommu_free_table()). For me > that means that PE and iommu_table have different lifetime. > > And I cannot find the exact place in this patchset where you call > iommu_free_table(), what do I miss? He has a point though... iommu_free_table() does a whole bunch of things in addition to kfree at the end. This is a discrepancy in the iommu.c code, we don't allocate the table, it's allocated by our callers, but we do free it in iommu_free_table(). My gut feeling is that we should fix that in the core by moving the kfree() out of iommu_free_table() and back into vio.c and pseries/iommu.c, the only two callers, otherwise we can't wrap the table structure inside another object if we are going to ever free it. Cheers, Ben.