From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751463AbdFHR5J (ORCPT ); Thu, 8 Jun 2017 13:57:09 -0400 Received: from mail-qt0-f178.google.com ([209.85.216.178]:34887 "EHLO mail-qt0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750822AbdFHR5H (ORCPT ); Thu, 8 Jun 2017 13:57:07 -0400 MIME-Version: 1.0 In-Reply-To: <20170608150540.rek7a4akuxm3k36l@piout.net> References: <20170608134811.60786-1-andriy.shevchenko@linux.intel.com> <20170608134811.60786-5-andriy.shevchenko@linux.intel.com> <20170608150540.rek7a4akuxm3k36l@piout.net> From: Andy Shevchenko Date: Thu, 8 Jun 2017 20:57:05 +0300 Message-ID: Subject: Re: [PATCH v1 04/25] lib/vsprintf: Print time and date in human readable format via %pt To: Alexandre Belloni Cc: Arnd Bergmann , Andy Shevchenko , Rasmus Villemoes , Greg Kroah-Hartman , Andrew Morton , Linux Kernel Mailing List , Alessandro Zummo , linux-rtc@vger.kernel.org, Bartlomiej Zolnierkiewicz , Dmitry Torokhov , Geert Uytterhoeven , Guan Xuetao , Ingo Molnar , Jason Wessel , Jonathan Corbet , Jonathan Hunter , Krzysztof Kozlowski , "Rafael J. Wysocki" , Thierry Reding Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 8, 2017 at 6:05 PM, Alexandre Belloni wrote: > On 08/06/2017 at 17:55:12 +0300, Andy Shevchenko wrote: >> On Thu, Jun 8, 2017 at 5:49 PM, Arnd Bergmann wrote: >> > On Thu, Jun 8, 2017 at 3:47 PM, Andy Shevchenko >> > wrote: >> >> There are users which print time and date represented by content of >> >> struct rtc_time in human readable format. >> >> >> >> Instead of open coding that each time introduce %pt[dt][rv] specifier. >> > >> > I really like the idea, and the implementation seems fine for this use case, but >> > before we reserve %pt for rtc_time, could we discuss whether we want >> > that for printing struct tm, struct timespec64, time64_t or ktime_t instead? >> >> How many users? For struct tm it's somelike 4 (which want to print its content). >> >> > I can see good reasons for pretty-printing any of them, but the namespace for >> > format strings is rather limited. >> > >> > struct rtc_time is almost the same as struct tm (the former has one extra >> > member), so maybe we can actually define them to be the same and >> > use one format string for both? >> >> The reason I decide to drop struct tm for now due to they are not >> compatible and I have got an interesting bugs. >> Verify tm_year member carefully. >> > > I understand this may not fit your debugging needs but what about pretty > printing time64_t and using rtc_tm_to_time64? There are two downsides as I can see: 1) conversion to and from just for that; 2) if you look closer to the patches rtc-* you may find cases where wday is also printed so, struct rtc_time still will be in use. So, I would go not to convert if there is no strong reason to do. -- With Best Regards, Andy Shevchenko