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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 00127C06511 for ; Wed, 3 Jul 2019 17:32:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CF40E218A4 for ; Wed, 3 Jul 2019 17:32:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="jFQPczeo" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727011AbfGCRcn (ORCPT ); Wed, 3 Jul 2019 13:32:43 -0400 Received: from hqemgate16.nvidia.com ([216.228.121.65]:11351 "EHLO hqemgate16.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726490AbfGCRcn (ORCPT ); Wed, 3 Jul 2019 13:32:43 -0400 Received: from hqpgpgate102.nvidia.com (Not Verified[216.228.121.13]) by hqemgate16.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Wed, 03 Jul 2019 10:32:41 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate102.nvidia.com (PGP Universal service); Wed, 03 Jul 2019 10:32:42 -0700 X-PGP-Universal: processed; by hqpgpgate102.nvidia.com on Wed, 03 Jul 2019 10:32:42 -0700 Received: from rcampbell-dev.nvidia.com (172.20.13.39) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Wed, 3 Jul 2019 17:32:40 +0000 Subject: Re: [PATCH 19/22] mm: always return EBUSY for invalid ranges in hmm_range_{fault,snapshot} To: Christoph Hellwig , Dan Williams , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Jason Gunthorpe , Ben Skeggs CC: Ira Weiny , , , , , , References: <20190701062020.19239-1-hch@lst.de> <20190701062020.19239-20-hch@lst.de> X-Nvconfidentiality: public From: Ralph Campbell Message-ID: <85c88d71-2c25-38ff-a4a3-bfd66fff72b7@nvidia.com> Date: Wed, 3 Jul 2019 10:32:39 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <20190701062020.19239-20-hch@lst.de> X-Originating-IP: [172.20.13.39] X-ClientProxiedBy: HQMAIL107.nvidia.com (172.20.187.13) To HQMAIL107.nvidia.com (172.20.187.13) Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1562175161; bh=h5APIAGCLtc3sbvDunYYsjAxWo0bLP7WU/0gBEeeI0w=; h=X-PGP-Universal:Subject:To:CC:References:X-Nvconfidentiality:From: Message-ID:Date:User-Agent:MIME-Version:In-Reply-To: X-Originating-IP:X-ClientProxiedBy:Content-Type:Content-Language: Content-Transfer-Encoding; b=jFQPczeoa9GgO31iCc1i+leEDWlzjjir863TTILBB/y92fjmJ/f1sRLtX+VAJ+7kT w92vvah6B8huA4GwU+UVeQT0gcXzN2h0pOn1OhPiqQgIiYhz+alEB4KdiyBILqdNjF iPKpJwcfB8ejE/ycfI+hpo2hU5HhQCvtjkyBzaQyOAlSWgEb0SBv3a75TxnJ6bQu96 N0rQy1PEp6S5xBst7hP92U8L+tvob0E2tubrjAKpvUgVgwpry+THodovSht9UYcLga YagJXvoKcVLlFOE7Nc+UP4wF3Mu6pxJqPDNSCJG6taQO+xhoGrUVb+lnZnXTS7ATQt SJRIeqmOivyvQ== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/30/19 11:20 PM, Christoph Hellwig wrote: > We should not have two different error codes for the same condition. In > addition this really complicates the code due to the special handling of > EAGAIN that drops the mmap_sem due to the FAULT_FLAG_ALLOW_RETRY logic > in the core vm. > > Signed-off-by: Christoph Hellwig Reviewed-by: Ralph Campbell Probably should update the "Return:" comment above hmm_range_snapshot() too. > --- > mm/hmm.c | 8 +++----- > 1 file changed, 3 insertions(+), 5 deletions(-) > > diff --git a/mm/hmm.c b/mm/hmm.c > index c85ed7d4e2ce..d125df698e2b 100644 > --- a/mm/hmm.c > +++ b/mm/hmm.c > @@ -974,7 +974,7 @@ long hmm_range_snapshot(struct hmm_range *range) > do { > /* If range is no longer valid force retry. */ > if (!range->valid) > - return -EAGAIN; > + return -EBUSY; > > vma = find_vma(hmm->mm, start); > if (vma == NULL || (vma->vm_flags & device_vma)) > @@ -1069,10 +1069,8 @@ long hmm_range_fault(struct hmm_range *range, bool block) > > do { > /* If range is no longer valid force retry. */ > - if (!range->valid) { > - up_read(&hmm->mm->mmap_sem); > - return -EAGAIN; > - } > + if (!range->valid) > + return -EBUSY; > > vma = find_vma(hmm->mm, start); > if (vma == NULL || (vma->vm_flags & device_vma)) >