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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 22DE8C4321D for ; Wed, 22 Aug 2018 11:11:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DC5EB214DA for ; Wed, 22 Aug 2018 11:11:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DC5EB214DA Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz 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 S1728850AbeHVOfe (ORCPT ); Wed, 22 Aug 2018 10:35:34 -0400 Received: from mx2.suse.de ([195.135.220.15]:57756 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728143AbeHVOfe (ORCPT ); Wed, 22 Aug 2018 10:35:34 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id C0866AFDF; Wed, 22 Aug 2018 11:11:04 +0000 (UTC) Subject: Re: [RFC v8 PATCH 3/5] mm: mmap: zap pages with read mmap_sem in munmap To: Yang Shi , mhocko@kernel.org, willy@infradead.org, ldufour@linux.vnet.ibm.com, kirill@shutemov.name, akpm@linux-foundation.org, peterz@infradead.org, mingo@redhat.com, acme@kernel.org, alexander.shishkin@linux.intel.com, jolsa@redhat.com, namhyung@kernel.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <1534358990-85530-1-git-send-email-yang.shi@linux.alibaba.com> <1534358990-85530-4-git-send-email-yang.shi@linux.alibaba.com> From: Vlastimil Babka Openpgp: preference=signencrypt Autocrypt: addr=vbabka@suse.cz; 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Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <1534358990-85530-4-git-send-email-yang.shi@linux.alibaba.com> Content-Type: text/plain; charset=utf-8 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 08/15/2018 08:49 PM, Yang Shi wrote: > + start_vma = munmap_lookup_vma(mm, start, end); > + if (!start_vma) > + goto out; > + if (IS_ERR(start_vma)) { > + ret = PTR_ERR(start_vma); > + goto out; > + } > + > + prev = start_vma->vm_prev; > + > + if (unlikely(uf)) { > + ret = userfaultfd_unmap_prep(start_vma, start, end, uf); > + if (ret) > + goto out; > + } > + You sure it's ok to redo this in case of goto regular path? The preparations have some side-effects... I would rather move this after the regular path check?