From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752230AbeC0KDX (ORCPT ); Tue, 27 Mar 2018 06:03:23 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:40814 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750978AbeC0KDV (ORCPT ); Tue, 27 Mar 2018 06:03:21 -0400 Date: Tue, 27 Mar 2018 12:03:18 +0200 From: Cornelia Huck To: Dong Jia Shi Cc: linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org, borntraeger@de.ibm.com, pasic@linux.vnet.ibm.com, pmorel@linux.vnet.ibm.com Subject: Re: [PATCH 3/4] vfio: ccw: set ccw->cda to NULL defensively Message-ID: <20180327120318.3fad36bc.cohuck@redhat.com> In-Reply-To: <20180327030809.GJ12194@bjsdjshi@linux.vnet.ibm.com> References: <20180321020822.86255-1-bjsdjshi@linux.vnet.ibm.com> <20180321020822.86255-4-bjsdjshi@linux.vnet.ibm.com> <20180326154753.327503ba.cohuck@redhat.com> <20180327030809.GJ12194@bjsdjshi@linux.vnet.ibm.com> Organization: Red Hat GmbH MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 27 Mar 2018 11:08:09 +0800 Dong Jia Shi wrote: > * Cornelia Huck [2018-03-26 15:47:53 +0200]: > > > On Wed, 21 Mar 2018 03:08:21 +0100 > > Dong Jia Shi wrote: > > > > > Let's avoid free on ccw->cda that points to a guest address > > > or a already freed memory area by setting it to NULL if memory > > > allocation didn't happen or failed. > > > > Does not hurt, I guess. > > > > > > > > Signed-off-by: Dong Jia Shi > > > --- > > > drivers/s390/cio/vfio_ccw_cp.c | 28 +++++++++++++++++++--------- > > > 1 file changed, 19 insertions(+), 9 deletions(-) > > > > > > diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c > > > index 3abc9770910a..5958c35ab343 100644 > > > --- a/drivers/s390/cio/vfio_ccw_cp.c > > > +++ b/drivers/s390/cio/vfio_ccw_cp.c > > > @@ -491,7 +491,7 @@ static int ccwchain_fetch_direct(struct ccwchain *chain, > > > struct ccw1 *ccw; > > > struct pfn_array_table *pat; > > > unsigned long *idaws; > > > - int idaw_nr; > > > + int idaw_nr, ret; > > > > > > ccw = chain->ch_ccw + idx; > > > > > > @@ -511,18 +511,20 @@ static int ccwchain_fetch_direct(struct ccwchain *chain, > > > * needed when translating a direct ccw to a idal ccw. > > > */ > > > pat = chain->ch_pat + idx; > > > - if (pfn_array_table_init(pat, 1)) > > > - return -ENOMEM; > > > - idaw_nr = pfn_array_alloc_pin(pat->pat_pa, cp->mdev, > > > + ret = pfn_array_table_init(pat, 1); > > > + if (ret) > > > + goto out_init; > > > + > > > + idaw_nr = ret = pfn_array_alloc_pin(pat->pat_pa, cp->mdev, > > > > Ugh, I don't like setting both at the same time... only set idaw_nr for > > ret > 0? (personal preference) > > > Ah, we don't need idaw_nr anymore. I think I should just replace it with > ret. Let's do that. > > > > ccw->cda, ccw->count); > > > - if (idaw_nr < 0) > > > - return idaw_nr; > > > + if (ret < 0) > > > + goto out_init; > > >