From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm1-f69.google.com (mail-wm1-f69.google.com [209.85.128.69]) by kanga.kvack.org (Postfix) with ESMTP id 3DBD18E0002 for ; Wed, 16 Jan 2019 15:38:36 -0500 (EST) Received: by mail-wm1-f69.google.com with SMTP id f193so1781246wme.8 for ; Wed, 16 Jan 2019 12:38:36 -0800 (PST) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id n203sor15950886wma.16.2019.01.16.12.38.34 for (Google Transport Security); Wed, 16 Jan 2019 12:38:34 -0800 (PST) MIME-Version: 1.0 References: <20190116181859.D1504459@viggo.jf.intel.com> <20190116181901.CAF85066@viggo.jf.intel.com> In-Reply-To: <20190116181901.CAF85066@viggo.jf.intel.com> From: Bjorn Helgaas Date: Wed, 16 Jan 2019 14:38:21 -0600 Message-ID: Subject: Re: [PATCH 1/4] mm/resource: return real error codes from walk failures Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-mm@kvack.org List-ID: To: Dave Hansen Cc: dave@sr71.net, Dan Williams , Dave Jiang , zwisler@kernel.org, vishal.l.verma@intel.com, thomas.lendacky@amd.com, Andrew Morton , mhocko@suse.com, linux-nvdimm@lists.01.org, Linux Kernel Mailing List , linux-mm@kvack.org, Huang Ying , Wu Fengguang , Borislav Petkov , baiyaowei@cmss.chinamobile.com, Takashi Iwai On Wed, Jan 16, 2019 at 12:25 PM Dave Hansen wrote: > > > From: Dave Hansen > > walk_system_ram_range() can return an error code either becuase *it* > failed, or because the 'func' that it calls returned an error. The > memory hotplug does the following: > > ret = walk_system_ram_range(..., func); > if (ret) > return ret; > > and 'ret' makes it out to userspace, eventually. The problem is, > walk_system_ram_range() failues that result from *it* failing (as > opposed to 'func') return -1. That leads to a very odd -EPERM (-1) > return code out to userspace. > > Make walk_system_ram_range() return -EINVAL for internal failures to > keep userspace less confused. > > This return code is compatible with all the callers that I audited. > > Cc: Dan Williams > Cc: Dave Jiang > Cc: Ross Zwisler > Cc: Vishal Verma > Cc: Tom Lendacky > Cc: Andrew Morton > Cc: Michal Hocko > Cc: linux-nvdimm@lists.01.org > Cc: linux-kernel@vger.kernel.org > Cc: linux-mm@kvack.org > Cc: Huang Ying > Cc: Fengguang Wu > > > Signed-off-by: Dave Hansen > --- > > b/kernel/resource.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff -puN kernel/resource.c~memory-hotplug-walk_system_ram_range-returns-neg-1 kernel/resource.c > --- a/kernel/resource.c~memory-hotplug-walk_system_ram_range-returns-neg-1 2018-12-20 11:48:41.810771934 -0800 > +++ b/kernel/resource.c 2018-12-20 11:48:41.814771934 -0800 > @@ -375,7 +375,7 @@ static int __walk_iomem_res_desc(resourc > int (*func)(struct resource *, void *)) > { > struct resource res; > - int ret = -1; > + int ret = -EINVAL; > > while (start < end && > !find_next_iomem_res(start, end, flags, desc, first_lvl, &res)) { > @@ -453,7 +453,7 @@ int walk_system_ram_range(unsigned long > unsigned long flags; > struct resource res; > unsigned long pfn, end_pfn; > - int ret = -1; > + int ret = -EINVAL; Don't you want a similar change in the powerpc version in arch/powerpc/mm/mem.c? > > start = (u64) start_pfn << PAGE_SHIFT; > end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1; > _ 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=-11.6 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,USER_IN_DEF_DKIM_WL 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 5BBC0C43387 for ; Wed, 16 Jan 2019 20:38:37 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 19CB6206C2 for ; Wed, 16 Jan 2019 20:38:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="JCWldirx" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 19CB6206C2 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id A951B8E0003; Wed, 16 Jan 2019 15:38:36 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id A45A08E0002; Wed, 16 Jan 2019 15:38:36 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 932FE8E0003; Wed, 16 Jan 2019 15:38:36 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from mail-wm1-f69.google.com (mail-wm1-f69.google.com [209.85.128.69]) by kanga.kvack.org (Postfix) with ESMTP id 3DBD18E0002 for ; Wed, 16 Jan 2019 15:38:36 -0500 (EST) Received: by mail-wm1-f69.google.com with SMTP id f193so1781246wme.8 for ; Wed, 16 Jan 2019 12:38:36 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:dkim-signature:mime-version:references :in-reply-to:from:date:message-id:subject:to:cc; bh=EXENUcZQeQc4GpVOepu2JqCrBL5FekqSojjxZTgabJE=; b=qAVPc8AMP88ruGa1j7mkRS2W1qyggvLPEN7g4u5l+R6UDM95Aa0QCMee35nsyHsXzb aNSogiMiD9IojpUi6UgsJ9pH38yO5P6YVhKWRjngFNa0Kami410k+EJHhw6cUH7fGTWc 3eCT8oEw4AySHU1a9kOb33QxCEoilHlMPvz7SqNsh+nQhlceP7kT+5tB8bQv3a09GbcY TBg6O8whRUy5PvUkQhJterdlu7GkLES1YI18xBayFFMs9TXt8rw0SWpYjgw5eoDH/cxo xsOILAcdhdp7s1/LLOvobagYRsZf+7iF678rz5BqN8lQYcXbl6SK4h+z5+dBjUk3LuJN 9u6w== X-Gm-Message-State: AJcUuketcSkOGAnEo+hQEKvO90snhbQlet1+DmGiw3WACNBI4joUOpXF c7CGfmDh7cYucYuyrcKUVMDQ4r/Rw3td0GsQgDArV8E/xdHzj5B/Fy7rp/l3nG0RQDqTMd8xoL0 gwwicWfdwS6XlQFnwUyPKDA1v7evZZcs+QlneJUsh/npgcvrKe9kNkWljJ0MHVLrSNs2DyEy4LV A3rx01XqA53BUZJHWcAx0h/Idc9JDT4sgQml2XhV4KZlR+k8zNxZ9vfdjuxofQ/7vcdyP9Iynsm ZZv2mrdyqI93DpMn9elw9jRorMI5ni0X/8smrHhQ4OMXN3Mlb4ANrFc813MXhs3A1XBnMyAkyk6 TXky9IIAtMA1peQOezua1/OQR9x3Jz2t1iphHjNEmPQMvfIT/PlT0JxB1KledAxGJhx4Eb99G0U P X-Received: by 2002:a1c:c181:: with SMTP id r123mr8984826wmf.8.1547671115723; Wed, 16 Jan 2019 12:38:35 -0800 (PST) X-Received: by 2002:a1c:c181:: with SMTP id r123mr8984790wmf.8.1547671114741; Wed, 16 Jan 2019 12:38:34 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1547671114; cv=none; d=google.com; s=arc-20160816; b=DFvo/5VKKyuQQQ6rQhRY4cvjrClfsWfHQR4XL5moG8kw6ktFfddgXi+mU/47BdZFP9 Crgluw+vEBkguzcdsr9D9aGmFUr1pbD1ATFPiA9tuiN+2YlQ+URWuxjXATzl61GNaxBv jGAsdLkh1wQj3vCgyR63zS5QX5bQGZL4e7cBxS3TSYwa/jiARIlUDpLWzKuj5vcSEYAf FKeufDeL3/Mg1QRcRZGOeR588B/77nYQPW4F+RxKi644P2aI9UZdWtxrEIV7asyuPGuw 0QOYgvStxdM1ZI1ubLlDTjc01wpRBuYApoju4IXHKgKVQurqd9S56gJacX1f9yYxbz2n xk+w== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:dkim-signature; bh=EXENUcZQeQc4GpVOepu2JqCrBL5FekqSojjxZTgabJE=; b=RbBWKj8kCq5p++QHSUH8PNOA9ITzSM+k8DR3nWHLmEnHG7/QMuwRfgH2NfO7Swabrz iWB6K3AD+JjOJcA4dLqRdFUSkkLCSqhvU0lmRUNTqrgBZwVQh9mHpfAIp+X2wSA4wfyX k2g2J/G+o9OX8fXf3QMnchKzwsw0r1QRrGQ8TulSHiakMdzF5ngGg3mBSgylTVicGf5L NxIiOmL9fiNEvqnQz9gGRgM9TUEQsuCRcSumdk5k1F10E2ELvXDgdzEmuSj6DTeNtrGt Cn6BLOju3JgkjE6unbAO4t7GK0DGGh/a/L0AW6a7uvN72Crsv2CvU9JCspIhaVCbS7eB IQsQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=JCWldirx; spf=pass (google.com: domain of bhelgaas@google.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=bhelgaas@google.com; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id n203sor15950886wma.16.2019.01.16.12.38.34 for (Google Transport Security); Wed, 16 Jan 2019 12:38:34 -0800 (PST) Received-SPF: pass (google.com: domain of bhelgaas@google.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=JCWldirx; spf=pass (google.com: domain of bhelgaas@google.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=bhelgaas@google.com; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=EXENUcZQeQc4GpVOepu2JqCrBL5FekqSojjxZTgabJE=; b=JCWldirxMg//hUX4ioKgbonPMZuWXWN6HEC9HdxBMzSAWVFoVoWJFm2Y1KiskwlPZW itiYT++UShcarFg/zFJy8KfTI6HqbRYAx+Evx7qIm3jOSs5MIbE4O0B4BNrPyARXDOuh KYtUN/4omxn44KaN83fCPBSMxtFKU26Cpa7PSMnCyXCyFIvYoGWRLqWdhqFnCvNYz6R2 bhyLV3sWl+Ry+Iavnwp1Y9cl8CTO0T6Yyf7rx7fXds+A3Q63fKpeqMH4+NiVCakFGIEa ukB4vm2Kzt9V0x/tHozpZDaq1KyFXdiu+LTze5Kf7P66vr1MMeZPfYZh+5FLzMfPMuRF ulJw== X-Google-Smtp-Source: ALg8bN7gpC1zQUf/Ur28gfRRSuGlQu5VnHpLdE4eoVuPZp4DpLFxmDk6C1d/4OcIeclkzK7A6gnxawWFV23BB9YbhG8= X-Received: by 2002:a1c:8d53:: with SMTP id p80mr9476229wmd.68.1547671114168; Wed, 16 Jan 2019 12:38:34 -0800 (PST) MIME-Version: 1.0 References: <20190116181859.D1504459@viggo.jf.intel.com> <20190116181901.CAF85066@viggo.jf.intel.com> In-Reply-To: <20190116181901.CAF85066@viggo.jf.intel.com> From: Bjorn Helgaas Date: Wed, 16 Jan 2019 14:38:21 -0600 Message-ID: Subject: Re: [PATCH 1/4] mm/resource: return real error codes from walk failures To: Dave Hansen Cc: dave@sr71.net, Dan Williams , Dave Jiang , zwisler@kernel.org, vishal.l.verma@intel.com, thomas.lendacky@amd.com, Andrew Morton , mhocko@suse.com, linux-nvdimm@lists.01.org, Linux Kernel Mailing List , linux-mm@kvack.org, Huang Ying , Wu Fengguang , Borislav Petkov , baiyaowei@cmss.chinamobile.com, Takashi Iwai Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Message-ID: <20190116203821.eC4AUN97WX1ThdkLeu6uzcczXPe8eXdKGtKisNB49Ns@z> On Wed, Jan 16, 2019 at 12:25 PM Dave Hansen wrote: > > > From: Dave Hansen > > walk_system_ram_range() can return an error code either becuase *it* > failed, or because the 'func' that it calls returned an error. The > memory hotplug does the following: > > ret = walk_system_ram_range(..., func); > if (ret) > return ret; > > and 'ret' makes it out to userspace, eventually. The problem is, > walk_system_ram_range() failues that result from *it* failing (as > opposed to 'func') return -1. That leads to a very odd -EPERM (-1) > return code out to userspace. > > Make walk_system_ram_range() return -EINVAL for internal failures to > keep userspace less confused. > > This return code is compatible with all the callers that I audited. > > Cc: Dan Williams > Cc: Dave Jiang > Cc: Ross Zwisler > Cc: Vishal Verma > Cc: Tom Lendacky > Cc: Andrew Morton > Cc: Michal Hocko > Cc: linux-nvdimm@lists.01.org > Cc: linux-kernel@vger.kernel.org > Cc: linux-mm@kvack.org > Cc: Huang Ying > Cc: Fengguang Wu > > > Signed-off-by: Dave Hansen > --- > > b/kernel/resource.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff -puN kernel/resource.c~memory-hotplug-walk_system_ram_range-returns-neg-1 kernel/resource.c > --- a/kernel/resource.c~memory-hotplug-walk_system_ram_range-returns-neg-1 2018-12-20 11:48:41.810771934 -0800 > +++ b/kernel/resource.c 2018-12-20 11:48:41.814771934 -0800 > @@ -375,7 +375,7 @@ static int __walk_iomem_res_desc(resourc > int (*func)(struct resource *, void *)) > { > struct resource res; > - int ret = -1; > + int ret = -EINVAL; > > while (start < end && > !find_next_iomem_res(start, end, flags, desc, first_lvl, &res)) { > @@ -453,7 +453,7 @@ int walk_system_ram_range(unsigned long > unsigned long flags; > struct resource res; > unsigned long pfn, end_pfn; > - int ret = -1; > + int ret = -EINVAL; Don't you want a similar change in the powerpc version in arch/powerpc/mm/mem.c? > > start = (u64) start_pfn << PAGE_SHIFT; > end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1; > _