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=-16.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=unavailable 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 7442AC433E0 for ; Fri, 12 Feb 2021 07:53:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1FFDB64E13 for ; Fri, 12 Feb 2021 07:53:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229958AbhBLHxU (ORCPT ); Fri, 12 Feb 2021 02:53:20 -0500 Received: from mail.kernel.org ([198.145.29.99]:46808 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229497AbhBLHxQ (ORCPT ); Fri, 12 Feb 2021 02:53:16 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id E732F64E13; Fri, 12 Feb 2021 07:52:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1613116356; bh=HpQHk0OqD+sZW6SvknIg2+jOr/x2orf6nVRPBzChn2A=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=mNRabWq6nE7HhAVGwLKpYDNptcxDLgLj4LcBHF2ySyfcVBC8SY4bF6fb2cMF7Ury+ z0HyrfWtG2HIDvcoIXstx5x/JRW2J9TjvrywenHeLsZWipcH6AKgSknfaWwwDl8VhG rnWLcHYucyQOsIl/Pxd3fNu7MwAeYyskImDcN67w= Date: Fri, 12 Feb 2021 08:52:33 +0100 From: Greg Kroah-Hartman To: shuo.a.liu@intel.com Cc: linux-next@vger.kernel.org, Stephen Rothwell , Randy Dunlap , linux-kernel@vger.kernel.org Subject: Re: [PATCH] virt: acrn: Fix vCPU removing code build error Message-ID: References: <20210212045724.77846-1-shuo.a.liu@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20210212045724.77846-1-shuo.a.liu@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Feb 12, 2021 at 12:57:24PM +0800, shuo.a.liu@intel.com wrote: > From: Shuo Liu > > vCPU removing code depends on CONFIG_HOTPLUG_CPU as it uses remove_cpu() > and add_cpu(). Make the vCPU removing interface building with > CONFIG_HOTPLUG_CPU. > > ../drivers/virt/acrn/hsm.c: In function ‘remove_cpu_store’: > ../drivers/virt/acrn/hsm.c:389:3: error: implicit declaration of function ‘remove_cpu’; [-Werror=implicit-function-declaration] > remove_cpu(cpu); > > ../drivers/virt/acrn/hsm.c:402:2: error: implicit declaration of function ‘add_cpu’; [-Werror=implicit-function-declaration] > add_cpu(cpu); > > Fixes: 279dcf693ac7 ("virt: acrn: Introduce an interface for Service VM to control vCPU") > Reported-by: Randy Dunlap > Acked-by: Randy Dunlap # build-tested > Signed-off-by: Shuo Liu > --- > drivers/virt/acrn/hsm.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/virt/acrn/hsm.c b/drivers/virt/acrn/hsm.c > index 1f6b7c54a1a4..e340788aacdf 100644 > --- a/drivers/virt/acrn/hsm.c > +++ b/drivers/virt/acrn/hsm.c > @@ -372,6 +372,7 @@ static int acrn_dev_release(struct inode *inode, struct file *filp) > return 0; > } > > +#ifdef CONFIG_HOTPLUG_CPU > static ssize_t remove_cpu_store(struct device *dev, > struct device_attribute *attr, > const char *buf, size_t count) > @@ -403,9 +404,12 @@ static ssize_t remove_cpu_store(struct device *dev, > return ret; > } > static DEVICE_ATTR_WO(remove_cpu); > +#endif > > static struct attribute *acrn_attrs[] = { > +#ifdef CONFIG_HOTPLUG_CPU > &dev_attr_remove_cpu.attr, > +#endif > NULL > }; > > Shouldn't the real solution for this be that remove_cpu() and add_cpu() have function prototypes for when this is not enabled in the kernel build? Putting #ifdef in .c files like this is not a good idea at all. Then, at runtime, you can determine if you need to create this sysfs file or not, as you do not want to expose it to userspace if the kernel can not handle it, right? thanks, greg k-h