From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 88745C433F5 for ; Sun, 21 Nov 2021 13:32:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237991AbhKUNfP (ORCPT ); Sun, 21 Nov 2021 08:35:15 -0500 Received: from mout.kundenserver.de ([212.227.126.134]:55073 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233735AbhKUNfP (ORCPT ); Sun, 21 Nov 2021 08:35:15 -0500 Received: from mail-oi1-f169.google.com ([209.85.167.169]) by mrelayeu.kundenserver.de (mreue010 [213.165.67.97]) with ESMTPSA (Nemesis) id 1MTR6K-1nE32o3bzg-00Togb for ; Sun, 21 Nov 2021 14:32:07 +0100 Received: by mail-oi1-f169.google.com with SMTP id 7so32100548oip.12 for ; Sun, 21 Nov 2021 05:32:06 -0800 (PST) X-Gm-Message-State: AOAM530pQ2ksPz4gdC22WjE5jMvY6irKEEPxs6Rl4uTP/BiPR2X33st9 qrqCoX1GASi0ct/xhwNYmiWdu7JKNlVwFFWEvrA= X-Google-Smtp-Source: ABdhPJxyHs8jQYRTeBiFU+eq5P3zltew6Z+4qTqSrV5gRgP3Dvi6VV6vXAp+I7ZNArHgO4PgQip0GKQ6vpyfaInpxkg= X-Received: by 2002:aca:accd:: with SMTP id v196mr14710148oie.108.1637501525594; Sun, 21 Nov 2021 05:32:05 -0800 (PST) MIME-Version: 1.0 References: <20211119113644.1600-1-alx.manpages@gmail.com> <20211120130104.185699-1-alx.manpages@gmail.com> <20211120130104.185699-9-alx.manpages@gmail.com> In-Reply-To: <20211120130104.185699-9-alx.manpages@gmail.com> From: Arnd Bergmann Date: Sun, 21 Nov 2021 14:31:49 +0100 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v2 08/20] Implement container_of_safe() in terms of container_of() To: Alejandro Colomar Cc: LKML , Andy Shevchenko , Arnd Bergmann , Alexey Dobriyan , Jani Nikula , Rasmus Villemoes , Kees Cook , Joe Perches Content-Type: text/plain; charset="UTF-8" X-Provags-ID: V03:K1:01DceEpeobilPRWPnRYhgiWzugCf4ijy18SXwNyVTU+29RpNXUN p0c2EUjLtrf3KHEGLEpad/Nuj4mefyS6NV4FH4zBYqtzDCIiHELpo8RWjKErWlWRIWRJrGx ZzoSJ8BNm2DdzJ4J62tH346ePsf7qWaQZB6a5H7PKrPoULGquz5Gkzcyg2Tk0M88djmXomm ljaTf1xwiFFk9xB7ilp/w== X-UI-Out-Filterresults: notjunk:1;V03:K0:Y7434Wx7BFE=:xJYxJIuAKIxuZ6TwnOGTqR gukezLETeYtoetcxBuNP7fy1dT/G5UdorYhR6YR1oIyj/XLA4Kw1bIMOyP2kDCooFs4Kn8npi SxnMFabcI2wwUVdqWwbk+fZQeuCW59VwCSFF4hKjJfcMFai+/Vpz5auh0e3gKBF+w4a5LQ7q6 AarnQ1Qz2bOplihvhLAmutaSEIhwXQGhn9K7kbeGunTgd2XSEn/+y4OPNwOueJXPtc7bxqxLr n2kPIntOfGGpjbLrgDf9nFpWwXpplbCmQ41kDCh4DrXs7xwLACMAmQpt+tuFputNSoFhMHJRi tKiJYFjnce7AsT16EDSwqXiMGOw9gyqMmb8G9a659PMtxQ5t8H3SeXviZmB7IZnrtmju6TnDL 6z+r7KqcyiD6/5KwCd4807jUkXC5s6/RMRSDRPrDgehS2YkHDJGiJZPiTNoBfSkihIWM/dHEp UoHagQ+KyQK/t3p0Wfk1vTgkedarCTs1ovduOAqzyjN5y3KMtzwlUG0hFM0pBTtWhBuZFWlR9 izRnV/MC4JkJy++ZoTM/m8X02h0kFhYemWvt7aPrj8vwMpLQrJsc7XXTRWSSGkw5gwb0QvScj /J8lI1eEHFqSckkJ7OsW0TASk4xYWmK3cISTxncuIDsBxkGamdHyveqJ2dPOmXn0sUy6OLjg4 D5KxZfIN/gEhV4koE2UVra8U+vKT471QaAbGNVzwZav4c/uyfupWmb2IHg88lIlH2g2dfcVos C5jHei6AR5SB1ftQk1FmS7/rMcds45BYnARoegS2pDyVlumg7FrAsi3bbWtkVDaan20ML6f78 5xsy1GMBwo+5AA+sX5CNR+NxQzRTh0i1gDR3SM1mDHAXXhceY0= Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Nov 20, 2021 at 2:00 PM Alejandro Colomar wrote: > > There's no more a need for the temporary variable __mptr, > since now it's only passed to functions that accept a 'const void *', > and everything can convert automatically to it, > reducing the need for the cast too. The purpose of the temporary variable is to avoid evaluating the macro multiple times, this is still required. > * If IS_ERR_OR_NULL(ptr), ptr is returned unchanged. > */ > -#define container_of_safe(ptr, type, member) ({ \ > - void *__mptr = (void *)(ptr); \ > - static_assert(__same_type(*(ptr), ((type *)0)->member) || \ > - __same_type(*(ptr), void), \ > - "pointer type mismatch in container_of_safe()"); \ > - IS_ERR_OR_NULL(__mptr) ? ERR_CAST(__mptr) : \ > - ((type *)(__mptr - offsetof(type, member))); }) > +#define container_of_safe(ptr, type, member) \ > + (IS_ERR_OR_NULL(ptr) ? ERR_CAST(ptr) : container_of(type, member)) It's possible that you may find a way to improve this macro using __auto_type, as a way to reduce the macro expansion further. Arnd