From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e23smtp07.au.ibm.com (e23smtp07.au.ibm.com [202.81.31.140]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id EAE371A000D for ; Wed, 25 Jun 2014 19:19:04 +1000 (EST) Received: from /spool/local by e23smtp07.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 25 Jun 2014 19:19:04 +1000 Received: from d23relay04.au.ibm.com (d23relay04.au.ibm.com [9.190.234.120]) by d23dlp02.au.ibm.com (Postfix) with ESMTP id 467472BB0054 for ; Wed, 25 Jun 2014 19:19:00 +1000 (EST) Received: from d23av01.au.ibm.com (d23av01.au.ibm.com [9.190.234.96]) by d23relay04.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id s5P92cCr34734102 for ; Wed, 25 Jun 2014 19:02:38 +1000 Received: from d23av01.au.ibm.com (localhost [127.0.0.1]) by d23av01.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s5P9Ixpo017456 for ; Wed, 25 Jun 2014 19:18:59 +1000 Date: Wed, 25 Jun 2014 17:18:57 +0800 From: Wei Yang To: Benjamin Herrenschmidt Subject: Re: [RFC PATCH V3 06/17] ppc/pnv: allocate pe->iommu_table dynamically Message-ID: <20140625091857.GB5573@richard> 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> <1403682997.4587.208.camel@pasglop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1403682997.4587.208.camel@pasglop> Cc: Wei Yang , Alexey Kardashevskiy , linux-pci@vger.kernel.org, gwshan@linux.vnet.ibm.com, yan@linux.vnet.ibm.com, bhelgaas@google.com, qiudayu@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org Reply-To: Wei Yang List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, Jun 25, 2014 at 05:56:37PM +1000, Benjamin Herrenschmidt wrote: >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. > Yes, this is another option. Move the kfree() outside could keep some logic in current code, like in pnv_pci_ioda_tce_invalidate(). We could get the tbl from a PE structure directly, instead of adding a field in tbl to point to the PE structure. >Cheers, >Ben. > > > -- Richard Yang Help you, Help me