From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-5.5 required=5.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham autolearn_force=no version=3.4.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id 1E9BB7D089 for ; Sun, 21 Oct 2018 22:28:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726950AbeJVGn6 (ORCPT ); Mon, 22 Oct 2018 02:43:58 -0400 Received: from imap.thunk.org ([74.207.234.97]:42716 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725882AbeJVGn6 (ORCPT ); Mon, 22 Oct 2018 02:43:58 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=thunk.org; s=ef5046eb; h=In-Reply-To:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Sender:Reply-To:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=Q9DiCbOolCu5PlQf1Y2Xqjbnd867NZevsa7QdTdTq4E=; b=W6ELe0HQ09UxmJVqo7ReN4Tcky 9ngw5qg4E0faHfsWaJ3MhYrM3sAL2ipM1oL2BTycRLE/j/b9ICVSE8Zz8CRfp+G1FlKgRUZpTJBAQ N9uC+b00yjam0o+A6lVO0LNO3wFDTBmUOJI/zMtbZX6QwfP8QIcJEtVK1cQPOLf/fCec=; Received: from root (helo=callcc.thunk.org) by imap.thunk.org with local-esmtp (Exim 4.89) (envelope-from ) id 1gEMBm-00026d-Qi; Sun, 21 Oct 2018 22:27:14 +0000 Received: by callcc.thunk.org (Postfix, from userid 15806) id 0527B7A2F4E; Sun, 21 Oct 2018 18:27:13 -0400 (EDT) Date: Sun, 21 Oct 2018 18:27:12 -0400 From: "Theodore Y. Ts'o" To: Miguel Ojeda Cc: Greg Kroah-Hartman , linux-kernel@vger.kernel.org, Dan Carpenter , Andreas Dilger , Masahiro Yamada , Michal Marek , Steven Rostedt , Mauro Carvalho Chehab , Olof Johansson , Konstantin Ryabitsev , "David S . Miller" , Andrey Ryabinin , Kees Cook , Thomas Gleixner , Ingo Molnar , Paul Lawrence , Sandipan Das , Andrey Konovalov , David Woodhouse , Will Deacon , Philippe Ombredanne , Paul Burton , David Rientjes , Willy Tarreau , Martin Sebor , Christopher Li , Jonathan Corbet , Geert Uytterhoeven , Rasmus Villemoes , Joe Perches , Arnd Bergmann , Dominique Martinet , Stefan Agner , Luc Van Oostenryck , Nick Desaulniers , Andrew Morton , Linus Torvalds , linux-doc@vger.kernel.org, linux-ext4@vger.kernel.org, linux-sparse@vger.kernel.org, linux-kbuild@vger.kernel.org Subject: Re: [PATCH 1/2] Compiler Attributes: add support for __fallthrough (gcc >= 7.1) Message-ID: <20181021222712.GI1617@thunk.org> Mail-Followup-To: "Theodore Y. Ts'o" , Miguel Ojeda , Greg Kroah-Hartman , linux-kernel@vger.kernel.org, Dan Carpenter , Andreas Dilger , Masahiro Yamada , Michal Marek , Steven Rostedt , Mauro Carvalho Chehab , Olof Johansson , Konstantin Ryabitsev , "David S . Miller" , Andrey Ryabinin , Kees Cook , Thomas Gleixner , Ingo Molnar , Paul Lawrence , Sandipan Das , Andrey Konovalov , David Woodhouse , Will Deacon , Philippe Ombredanne , Paul Burton , David Rientjes , Willy Tarreau , Martin Sebor , Christopher Li , Jonathan Corbet , Geert Uytterhoeven , Rasmus Villemoes , Joe Perches , Arnd Bergmann , Dominique Martinet , Stefan Agner , Luc Van Oostenryck , Nick Desaulniers , Andrew Morton , Linus Torvalds , linux-doc@vger.kernel.org, linux-ext4@vger.kernel.org, linux-sparse@vger.kernel.org, linux-kbuild@vger.kernel.org References: <20181021171414.22674-1-miguel.ojeda.sandonis@gmail.com> <20181021171414.22674-2-miguel.ojeda.sandonis@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181021171414.22674-2-miguel.ojeda.sandonis@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: tytso@thunk.org X-SA-Exim-Scanned: No (on imap.thunk.org); SAEximRunCond expanded to false Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Sun, Oct 21, 2018 at 07:14:13PM +0200, Miguel Ojeda wrote: > From the GCC manual: > > fallthrough > > The fallthrough attribute with a null statement serves as a > fallthrough statement. It hints to the compiler that a statement > that falls through to another case label, or user-defined label > in a switch statement is intentional and thus the -Wimplicit-fallthrough > warning must not trigger. The fallthrough attribute may appear > at most once in each attribute list, and may not be mixed with > other attributes. It can only be used in a switch statement > (the compiler will issue an error otherwise), after a preceding > statement and before a logically succeeding case label, > or user-defined label. > > https://gcc.gnu.org/onlinedocs/gcc/Statement-Attributes.html Do we know if coverity understands the fallthrough attribute? One of the reasons why I started using /* fallthrough */ is because it kept Coverity happy. If the conversion from /* fallthrough */ to the __fallthrough__ attribute means that we start gethting a lot of Coverity warnings, that would be unfortunate. OTOH, if this is getting standardized, maybe we can get Coverity to understand this attribute? - Ted