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=-7.0 required=3.0 tests=INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 93AE2C43387 for ; Thu, 20 Dec 2018 13:43:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6C47621852 for ; Thu, 20 Dec 2018 13:43:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732883AbeLTNnB (ORCPT ); Thu, 20 Dec 2018 08:43:01 -0500 Received: from mail-pf1-f195.google.com ([209.85.210.195]:36222 "EHLO mail-pf1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729096AbeLTNnA (ORCPT ); Thu, 20 Dec 2018 08:43:00 -0500 Received: by mail-pf1-f195.google.com with SMTP id b85so961315pfc.3 for ; Thu, 20 Dec 2018 05:43:00 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=uvXH82qG+vk0v23eTDrf0/ym40QVLBTETdMdA9Hq7ag=; b=koy6Jp6EotatIOuqe00+FGp14lmTFMwS9d+Dx67QcLWYmMbfDawhJVfxPMvj2Lj//z y1v3fc/vK/tMeong7FH3ON+NX14q6jN4QPhVWIYso7i38ZYcSuM/+da7+y/IQVpTlieC Po1T8Pmp58Shw9vR1YHEmgMJLnzcG/4WQLqKQ0LFxvny6YuOW2tQgJFNxJWMXM1C3mAg iOV87M8ns7mMmn86WBQ1Dc99vdv3Vg2zvbf/LNvRpwbuSrSrRIcgNaJi+QiLK8arAvsu Mcs2ICuP2LODsc7vd5SMEt/IJsU44mHIjNQzHCl/cTn/gxEvB5ytVjtARPShLCej0fan YlTg== X-Gm-Message-State: AA+aEWaP3z81NZKtSOrZtu4Q4loJmGbMG6QOH2yRw8N08WzPmRyGoOVT vDapHzoGn9ntN8xjVjd28WTjyg== X-Google-Smtp-Source: AFSGD/WnUzFMtUCzXQ/tnrH2+kto/438gwgSp1dSOUg68XKivku7uGPC7D4XfyoYrto2vNdk+XL57Q== X-Received: by 2002:a62:2044:: with SMTP id g65mr24260734pfg.127.1545313379591; Thu, 20 Dec 2018 05:42:59 -0800 (PST) Received: from bsingh.kernel.org ([125.16.97.118]) by smtp.gmail.com with ESMTPSA id l5sm32489776pgu.86.2018.12.20.05.42.56 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 20 Dec 2018 05:42:58 -0800 (PST) Subject: Re: [PATCH v2] hpet: Fix missing '=' character in the __setup() code of hpet_mmap_enable To: Greg KH Cc: clemens@ladisch.de, arnd@arndb.de, linux-kernel@vger.kernel.org, stable@vger.kernel.org References: <20181220120524.30732-1-bsingh@redhat.com> <20181220122932.GB17138@kroah.com> From: Buland Singh Message-ID: Date: Thu, 20 Dec 2018 19:12:55 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.0 MIME-Version: 1.0 In-Reply-To: <20181220122932.GB17138@kroah.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/20/18 5:59 PM, Greg KH wrote: > On Thu, Dec 20, 2018 at 05:35:24PM +0530, Buland Singh wrote: >> Commit '3d035f580699 ("drivers/char/hpet.c: allow user controlled mmap for >> user processes")' introduced a new kernel command line parameter hpet_mmap, >> that is required to expose the memory map of the HPET registers to >> user-space. Unfortunately the kernel command line parameter 'hpet_mmap' is >> broken and never takes effect due to missing '=' character in the __setup() >> code of hpet_mmap_enable. >> >> Before this patch: >> >> dmesg output with the kernel command line parameter hpet_mmap=1 >> >> [ 0.204152] HPET mmap disabled >> >> dmesg output with the kernel command line parameter hpet_mmap=0 >> >> [ 0.204192] HPET mmap disabled >> >> After this patch: >> >> dmesg output with the kernel command line parameter hpet_mmap=1 >> >> [ 0.203945] HPET mmap enabled >> >> dmesg output with the kernel command line parameter hpet_mmap=0 >> >> [ 0.204652] HPET mmap disabled >> >> Fixes: 3d035f580699 ("drivers/char/hpet.c: allow user controlled mmap for user processes") >> Signed-off-by: Buland Singh >> --- >> drivers/char/hpet.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c >> index 4a22b4b41aef..9bffcd37cc7b 100644 >> --- a/drivers/char/hpet.c >> +++ b/drivers/char/hpet.c >> @@ -377,7 +377,7 @@ static __init int hpet_mmap_enable(char *str) >> pr_info("HPET mmap %s\n", hpet_mmap_enabled ? "enabled" : "disabled"); >> return 1; >> } >> -__setup("hpet_mmap", hpet_mmap_enable); >> +__setup("hpet_mmap=", hpet_mmap_enable); Hello Greag, > This has _never_ worked? Since 3.13? Yes, that's true :) > Why not just remove the thing as it is obvious no one actually has ever used it. > That would make the code even simpler :) Data Plane Development Kit (DPDK)[1] provides API that requires the CONFIG_HPET_MMAP kernel configuration option to be enabled[2]. Some end users might want to use the HPET MMAP functionality within the application. Regards, Buland Singh [1] https://www.dpdk.org [2] https://doc.dpdk.org/guides-18.08/linux_gsg/enable_func.html