From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754379AbaEaH4c (ORCPT ); Sat, 31 May 2014 03:56:32 -0400 Received: from mail-ig0-f178.google.com ([209.85.213.178]:43917 "EHLO mail-ig0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751982AbaEaH4a (ORCPT ); Sat, 31 May 2014 03:56:30 -0400 MIME-Version: 1.0 In-Reply-To: <1401480116-1973111-2-git-send-email-arnd@arndb.de> References: <1401480116-1973111-1-git-send-email-arnd@arndb.de> <1401480116-1973111-2-git-send-email-arnd@arndb.de> Date: Sat, 31 May 2014 09:56:29 +0200 X-Google-Sender-Auth: VzjDMnvWK7DlZCe8yO4D_inpWtg Message-ID: Subject: Re: [RFC 01/32] fs: introduce new 'struct inode_time' From: Geert Uytterhoeven To: Arnd Bergmann Cc: "linux-kernel@vger.kernel.org" , Linux-Arch , "Joseph S. Myers" , John Stultz , Christoph Hellwig , Thomas Gleixner , Ley Foon Tan , "H. Peter Anvin" , Linux FS Devel Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Arnd, On Fri, May 30, 2014 at 10:01 PM, Arnd Bergmann wrote: > + * The variant using bit fields is less efficient to access, but > + * small and has a wider range as the 32-bit one, plus it keeps > + * the signedness of the original timespec. > + */ > +struct inode_time { > + long long tv_sec : 34; > + int tv_nsec : 30; > +}; Don't you need 31 bits for tv_nsec, to accommodate for the sign bit? I know you won't really store negative numbers there, but storing a large positive number will become negative on read out, won't it? Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds