Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754822AbdGJVXe (ORCPT ); Mon, 10 Jul 2017 17:23:34 -0400 Received: from vmicros1.altlinux.org ([194.107.17.57]:42378 "EHLO vmicros1.altlinux.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754503AbdGJVXd (ORCPT ); Mon, 10 Jul 2017 17:23:33 -0400 Date: Tue, 11 Jul 2017 00:23:21 +0300 From: Gleb Fotengauer-Malinovskiy To: Christian Borntraeger Cc: Paolo Bonzini , Radim =?utf-8?B?S3LEjW3DocWZ?= , Claudio Imbrenda , "Dmitry V. Levin" , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] KVM: s390: Fix KVM_S390_GET_CMMA_BITS ioctl definition Message-ID: <20170710212321.GB2703@glebfm.cloud.tilaa.com> References: <20170710144410.GA10359@glebfm.cloud.tilaa.com> <09c0760e-729d-548a-c3c4-b3afd9e67225@de.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <09c0760e-729d-548a-c3c4-b3afd9e67225@de.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 773 Lines: 22 On Mon, Jul 10, 2017 at 08:43:12PM +0200, Christian Borntraeger wrote: > On 07/10/2017 04:44 PM, Gleb Fotengauer-Malinovskiy wrote: > > This ioctl actually writes to parameter too. > > Maybe rephrase that to: > The kernel does not only read struct kvm_s390_cmma_log for KVM_S390_GET_CMMA_BITS, > it also writes back a return value making this _IOWR instead of _IOW. Ok, see v2. > > Fixes: 4036e387 ("KVM: s390: ioctls to get and set guest storage attributes") > > Signed-off-by: Gleb Fotengauer-Malinovskiy > Acked-by: Christian Borntraeger > > > Out of curiosity, how did you notice that? I regenerated strace's ioctl lists. It was obvious from the diff that *GET* and *SET* could not be both _IOC_WRITE. -- glebfm