From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 278331A0205 for ; Wed, 13 May 2015 22:51:50 +1000 (AEST) Date: Wed, 13 May 2015 14:51:36 +0200 From: Thomas Huth To: Alexey Kardashevskiy Subject: Re: [PATCH kernel v10 05/34] powerpc/iommu: Always release iommu_table in iommu_free_table() Message-ID: <20150513145136.1a85f536@thh440s> In-Reply-To: <5552EF78.6020301@ozlabs.ru> References: <1431358763-24371-1-git-send-email-aik@ozlabs.ru> <1431358763-24371-6-git-send-email-aik@ozlabs.ru> <20150513053337.GA479@gwshan> <5552EF78.6020301@ozlabs.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Cc: Wei Yang , Gavin Shan , linux-kernel@vger.kernel.org, Alex Williamson , Paul Mackerras , linuxppc-dev@lists.ozlabs.org, David Gibson List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, 13 May 2015 16:30:16 +1000 Alexey Kardashevskiy wrote: > On 05/13/2015 03:33 PM, Gavin Shan wrote: > > On Tue, May 12, 2015 at 01:38:54AM +1000, Alexey Kardashevskiy wrote: > >> At the moment iommu_free_table() only releases memory if > >> the table was initialized for the platform code use, i.e. it had > >> it_map initialized (which purpose is to track DMA memory space use). > >> > >> With dynamic DMA windows, we will need to be able to release > >> iommu_table even if it was used for VFIO in which case it_map is NULL > >> so does the patch. > >> > >> Signed-off-by: Alexey Kardashevskiy > > > > Reviewed-by: Gavin Shan > > > >> --- > >> arch/powerpc/kernel/iommu.c | 3 +-- > >> 1 file changed, 1 insertion(+), 2 deletions(-) > >> > >> diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c > >> index 3d47eb3..2c02d4c 100644 > >> --- a/arch/powerpc/kernel/iommu.c > >> +++ b/arch/powerpc/kernel/iommu.c > >> @@ -714,8 +714,7 @@ void iommu_free_table(struct iommu_table *tbl, const char *node_name) > >> unsigned int order; > >> > >> if (!tbl || !tbl->it_map) { > >> - printk(KERN_ERR "%s: expected TCE map for %s\n", __func__, > >> - node_name); > >> + kfree(tbl); > > > > I'm not sure if the "tbl" needs to be checked against NULL as kfree() already > > has the check. But it looks a bit strange to free NULL "tbl" from the code > > itself. > > Yeah, looks a bit weird, agree, I'll change but in general kfree/vfree/... > - they all check the passed pointer for NULL. But if tbl is NULL, the tbl->it_map check will fail, won't it? So in this case, I think you have to keep it. Thomas