Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751242Ab0HUCP7 (ORCPT ); Fri, 20 Aug 2010 22:15:59 -0400 Received: from mx4-phx2.redhat.com ([209.132.183.25]:41063 "EHLO mx02.colomx.prod.int.phx2.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751027Ab0HUCP4 convert rfc822-to-8bit (ORCPT ); Fri, 20 Aug 2010 22:15:56 -0400 Date: Fri, 20 Aug 2010 22:15:41 -0400 (EDT) From: Miloslav Trmac To: Stefan Richter Cc: Herbert Xu , linux-crypto@vger.kernel.org, Nikos Mavrogiannopoulos , Neil Horman , linux-kernel@vger.kernel.org Message-ID: <1833173750.1044971282356941800.JavaMail.root@zmail07.collab.prod.int.phx2.redhat.com> In-Reply-To: <4C6E7C1A.1070203@s5r6.in-berlin.de> Subject: Re: [PATCH 06/19] Add ioctl() argument and attribute handling utils MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT X-Originating-IP: [10.5.5.71] X-Mailer: Zimbra 5.0.21_GA_3150.RHEL4_64 (ZimbraWebClient - FF3.0 (Linux)/5.0.21_GA_3150.RHEL4_64) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1388 Lines: 32 ----- "Stefan Richter" wrote: > Miloslav Trmač wrote: > > --- /dev/null > > +++ b/crypto/userspace/utils.c > [...] > > +#ifdef CONFIG_COMPAT > > +/* max() is too clever for compile-time constants */ > > +#define CONST_MAX(A, B) ((A) > (B) ? (A) : (B)) > > + > > +#define MAX_SESSION_INPUT_DATA_SIZE \ > > + (CONST_MAX(sizeof(struct ncr_session_input_data), \ > > + sizeof(struct compat_ncr_session_input_data))) > > +#define MAX_SESSION_OUTPUT_BUFFER_SIZE \ > > + (CONST_MAX(sizeof(struct ncr_session_output_buffer), \ > > + sizeof(struct compat_ncr_session_output_buffer))) > > + > > +#else /* !CONFIG_COMPAT */ > > + > > +#define MAX_SESSION_INPUT_DATA_SIZE (sizeof(struct ncr_session_input_data)) > > +#define MAX_SESSION_OUTPUT_BUFFER_SIZE \ > > + (sizeof(struct ncr_session_output_buffer)) > > + > > +#endif /* !CONFIG_COMPAT */ > > struct compat_xyz cannot be bigger than struct xyz, can it? Perhaps not, but the code has been written and it's easier to keep it than to speculate :) It also helps document the fact that the data format depends on properties of the userspace. Mirek -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/