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 X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AF9A3CA9EA0 for ; Tue, 22 Oct 2019 17:35:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 828462084B for ; Tue, 22 Oct 2019 17:35:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1571765733; bh=Jld/hYcxZXmjGFVuWBdEY4QI+QyPIanxZKbLtqBLGBc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=Rp8rF1W1EgCX620W795CHknX/e8Dyb117fRDD4F0BJvdjbW0i5FsA4dyFT3Etc/Kw I3HA/anMwUrlgoKUO/AfBzyOZlUza3bqlCF8BLpfY+QAsBuJRBrMmb0PrlzHQO5/d3 8mYRTRrNYTYVPIYsl2uawxPHYjSAovq87VE19uZ8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732296AbfJVRfc (ORCPT ); Tue, 22 Oct 2019 13:35:32 -0400 Received: from mail.kernel.org ([198.145.29.99]:35486 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725837AbfJVRfc (ORCPT ); Tue, 22 Oct 2019 13:35:32 -0400 Received: from localhost (mobile-166-172-186-56.mycingular.net [166.172.186.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B094320700; Tue, 22 Oct 2019 17:35:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1571765730; bh=Jld/hYcxZXmjGFVuWBdEY4QI+QyPIanxZKbLtqBLGBc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=KjIZP5hfgFgUn1+Ljz18nxHSEXDVd7I1a8ueHM1nX8sqKYwTPALZAdaZeymD9A5Xk AhqKSe2drZC6ffhxX2VDu2wyGx51R4WPVjG0f6K8p+Z2h7rwP81FZEar+clOopjyBk JWILQvQH0HfCGebHAWRAKurHRkWaeIRbs5Klfa/c= Date: Tue, 22 Oct 2019 13:35:27 -0400 From: Greg Kroah-Hartman To: Joe Perches Cc: Geert Uytterhoeven , Ludovic Desroches , Ulf Hansson , Nicolas Ferre , Alexandre Belloni , Jaehoon Chung , "David S . Miller" , "Rafael J . Wysocki" , Johannes Berg , Linux MMC List , Linux ARM , netdev , linux-wireless , Linux Kernel Mailing List Subject: Re: [PATCH 1/7] debugfs: Add debugfs_create_xul() for hexadecimal unsigned long Message-ID: <20191022173527.GD230934@kroah.com> References: <20191021143742.14487-1-geert+renesas@glider.be> <20191021143742.14487-2-geert+renesas@glider.be> <0f91839d858fcb03435ebc85e61ee4e75371ff37.camel@perches.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.12.2 (2019-09-21) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Oct 22, 2019 at 02:07:34AM -0700, Joe Perches wrote: > On Tue, 2019-10-22 at 10:03 +0200, Geert Uytterhoeven wrote: > > Hi Joe, > > Hey again Geert. > > > On Mon, Oct 21, 2019 at 5:37 PM Joe Perches wrote: > > > On Mon, 2019-10-21 at 16:37 +0200, Geert Uytterhoeven wrote: > > > > The existing debugfs_create_ulong() function supports objects of > > > > type "unsigned long", which are 32-bit or 64-bit depending on the > > > > platform, in decimal form. To format objects in hexadecimal, various > > > > debugfs_create_x*() functions exist, but all of them take fixed-size > > > > types. > > > > > > > > Add a debugfs helper for "unsigned long" objects in hexadecimal format. > > > > This avoids the need for users to open-code the same, or introduce > > > > bugs when casting the value pointer to "u32 *" or "u64 *" to call > > > > debugfs_create_x{32,64}(). > > > [] > > > > diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h > > > [] > > > > @@ -356,4 +356,14 @@ static inline ssize_t debugfs_write_file_bool(struct file *file, > > > > > > > > #endif > > > > > > > > +static inline void debugfs_create_xul(const char *name, umode_t mode, > > > > + struct dentry *parent, > > > > + unsigned long *value) > > > > +{ > > > > + if (sizeof(*value) == sizeof(u32)) > > > > + debugfs_create_x32(name, mode, parent, (u32 *)value); > > > > + else > > > > + debugfs_create_x64(name, mode, parent, (u64 *)value); > > > > > > trivia: the casts are unnecessary. > > > > They are necessary, in both calls (so using #ifdef as suggested below > > won't help): > > Silly thinko, (I somehow thought the compiler would > eliminate the code after the branch not taken, but > of course it has to compile it first... oops) > though the #ifdef should work. > > > > This might be more sensible using #ifdef > > > > > > static inline void debugfs_create_xul(const char *name, umode_t mode, > > > struct dentry *parent, > > > unsigned long *value) > > > { > > > #if BITS_PER_LONG == 64 > > > debugfs_create_x64(name, mode, parent, value); > > > #else > > > debugfs_create_x32(name, mode, parent, value); > > > #endif > > > } > > > > ... at the expense of the compiler checking only one branch. > > > > Just like "if (IS_ENABLED(CONFIG_)" (when possible) is preferred > > over "#ifdef CONFIG_" because of compile-coverage, I think using > > "if" here is better than using "#if". > > True if all compilers will always eliminate the unused branch. Good ones will, we don't care about bad ones :)