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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIMWL_WL_MED 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 A62EFC433F5 for ; Mon, 27 Aug 2018 14:28:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5F5D0208B9 for ; Mon, 27 Aug 2018 14:28:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=bgdev-pl.20150623.gappssmtp.com header.i=@bgdev-pl.20150623.gappssmtp.com header.b="TfmGIHmg" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5F5D0208B9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bgdev.pl Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727604AbeH0SPs (ORCPT ); Mon, 27 Aug 2018 14:15:48 -0400 Received: from mail-io0-f193.google.com ([209.85.223.193]:43660 "EHLO mail-io0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726953AbeH0SPs (ORCPT ); Mon, 27 Aug 2018 14:15:48 -0400 Received: by mail-io0-f193.google.com with SMTP id y10-v6so12943726ioa.10 for ; Mon, 27 Aug 2018 07:28:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bgdev-pl.20150623.gappssmtp.com; s=20150623; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=BaOFoQl6DHDzuOJu8LPfRCgtPPF12Rh6t1zSvya2qF8=; b=TfmGIHmgzXvPi7OSuDK83NSOLfijjq9+nKXjpyZu/fm29pFCa4BiXk//w2VhlieCbM HvOO18xsbJed9EyVxml4zhe4v6LLvxvzup858wwOQbVfwWSo4yiROSiM1ImD7gfre9EC YPWD0SlczB6TWBj3UJ+kElNi8U2WEEnv25bLVK0uZvK6D3JD5QPM4RcitUWzW8Us1GSb 3+yxBhLE8+iEPOj76x0FbCCFeB6wLMFA1F8WrLCK5VFenQShpogaavPT0/znJNDs98/c 0iKr6R9IxVa36aPkii/IvTWR5PbEMsHPkqVL9m4oIsKcg85u/YkFoxB0WwhM7LwezIyZ Mnag== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=BaOFoQl6DHDzuOJu8LPfRCgtPPF12Rh6t1zSvya2qF8=; b=uCm13COzXpOpWioY8VRjpnhuu+gj5/58TzWJNcPyhQK9wnK/hC2LjhHDPYdOum4W5v KDvGI9F6hb2L97CwOnwfOJ/V6ZTh5v8c/Sf/8luo4G9XVAuRAvGTfPt4Bu8IkPmCWCmX 6iBfBxeBobkWg5P25RA+rYZBuwzpYZBkqO9Vj3b5tvquDSUdmeYciEsEfoRnM28HjAeI W+0E/IwjtXalEYFAYZcEB4qHEtvOJwBCml5PFSRLO+QWCZFFw5rRmX4mBQMMxKASw+AS HzsvRqFJaVU5OBOlLR6K152db3q3v9l6l4iW6MG5JdLKc3ohQWfmVXC46oMpPRyRdJV+ qYng== X-Gm-Message-State: APzg51C8ak6gZE0N0VXbYamsK5eSksk/zxw816SqTNQa6gr0ndJXiUrT XuHvb7drBNovhNqhrVzpwIUfyRDhCMnhAnLBGNlXDg== X-Google-Smtp-Source: ANB0VdawUhwnbyDZyvLoQMtzwv8WAgW2PjbISF4bqsvt6C34tiMI8Azq+Gw8QUkWGno9uFXrJq9hizAVMt4UXFlc1es= X-Received: by 2002:a6b:9157:: with SMTP id t84-v6mr10349932iod.187.1535380136343; Mon, 27 Aug 2018 07:28:56 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:a5e:9402:0:0:0:0:0 with HTTP; Mon, 27 Aug 2018 07:28:55 -0700 (PDT) In-Reply-To: <20180827103353.GB13848@rapoport-lnx> References: <20180827082101.5036-1-brgl@bgdev.pl> <20180827103353.GB13848@rapoport-lnx> From: Bartosz Golaszewski Date: Mon, 27 Aug 2018 16:28:55 +0200 Message-ID: Subject: Re: [PATCH 1/2] devres: provide devm_kstrdup_const() To: Mike Rapoport Cc: Michael Turquette , Stephen Boyd , Greg Kroah-Hartman , "Rafael J . Wysocki" , Arend van Spriel , Ulf Hansson , Bjorn Helgaas , Vivek Gautam , Robin Murphy , Joe Perches , Heikki Krogerus , Andrew Morton , Michal Hocko , Al Viro , Jonathan Corbet , Roman Gushchin , Huang Ying , Kees Cook , Bjorn Andersson , linux-clk , Linux Kernel Mailing List , linux-mm@kvack.org Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2018-08-27 12:33 GMT+02:00 Mike Rapoport : > On Mon, Aug 27, 2018 at 10:21:00AM +0200, Bartosz Golaszewski wrote: >> Provide a resource managed version of kstrdup_const(). This variant >> internally calls devm_kstrdup() on pointers that are outside of >> .rodata section. Also provide a corresponding version of devm_kfree(). >> >> Signed-off-by: Bartosz Golaszewski >> --- >> include/linux/device.h | 2 ++ >> mm/util.c | 35 +++++++++++++++++++++++++++++++++++ >> 2 files changed, 37 insertions(+) >> >> diff --git a/include/linux/device.h b/include/linux/device.h >> index 8f882549edee..f8f5982d26b2 100644 >> --- a/include/linux/device.h >> +++ b/include/linux/device.h >> @@ -693,7 +693,9 @@ static inline void *devm_kcalloc(struct device *dev, >> return devm_kmalloc_array(dev, n, size, flags | __GFP_ZERO); >> } >> extern void devm_kfree(struct device *dev, void *p); >> +extern void devm_kfree_const(struct device *dev, void *p); >> extern char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp) __malloc; >> +extern char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t gfp); >> extern void *devm_kmemdup(struct device *dev, const void *src, size_t len, >> gfp_t gfp); >> >> diff --git a/mm/util.c b/mm/util.c >> index d2890a407332..6d1f41b5775e 100644 >> --- a/mm/util.c >> +++ b/mm/util.c >> @@ -39,6 +39,20 @@ void kfree_const(const void *x) >> } >> EXPORT_SYMBOL(kfree_const); >> >> +/** >> + * devm_kfree_const - Resource managed conditional kfree >> + * @dev: device this memory belongs to >> + * @p: memory to free >> + * >> + * Function calls devm_kfree only if @p is not in .rodata section. >> + */ >> +void devm_kfree_const(struct device *dev, void *p) >> +{ >> + if (!is_kernel_rodata((unsigned long)p)) >> + devm_kfree(dev, p); >> +} >> +EXPORT_SYMBOL(devm_kfree_const); >> + >> /** >> * kstrdup - allocate space for and copy an existing string >> * @s: the string to duplicate >> @@ -78,6 +92,27 @@ const char *kstrdup_const(const char *s, gfp_t gfp) >> } >> EXPORT_SYMBOL(kstrdup_const); >> >> +/** >> + * devm_kstrdup_const - resource managed conditional string duplication >> + * @dev: device for which to duplicate the string >> + * @s: the string to duplicate >> + * @gfp: the GFP mask used in the kmalloc() call when allocating memory >> + * >> + * Function returns source string if it is in .rodata section otherwise it >> + * fallbacks to devm_kstrdup. > > Please make it proper "Returns:" description and move to the end of the > comment. See Documentation/doc-guide/kernel-doc.rst. > Sure. >> + * Strings allocated by devm_kstrdup_const will be automatically freed when >> + * the associated device is detached. >> + */ >> +char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t gfp) >> +{ >> + if (is_kernel_rodata((unsigned long)s)) >> + return s; >> + >> + return devm_kstrdup(dev, s, gfp); >> +} >> +EXPORT_SYMBOL(devm_kstrdup_const); >> + > > The devm_ variants seem to belong to drivers/base/devres.c rather than > mm/util.c > Not all devm_ variants live in drivers/base/devres.c, many subsystems implement them locally. In this case we need to choose between exporting is_kernel_rodata() and putting devm_kstrdup_const() in mm/util.c. I chose the latter, since it's cleaner. Bart >> /** >> * kstrndup - allocate space for and copy an existing string >> * @s: the string to duplicate >> -- >> 2.18.0 >> > > -- > Sincerely yours, > Mike. >