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=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,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 E1788C433FE for ; Thu, 23 Sep 2021 23:17:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CD6C660E94 for ; Thu, 23 Sep 2021 23:17:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243576AbhIWXTO (ORCPT ); Thu, 23 Sep 2021 19:19:14 -0400 Received: from mail.kernel.org ([198.145.29.99]:48648 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243572AbhIWXTM (ORCPT ); Thu, 23 Sep 2021 19:19:12 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3A9A160E94; Thu, 23 Sep 2021 23:17:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1632439059; bh=aovSY1+j/p4VcwH3XgkVFJ6AKhHLQs9U16f85Ij55u4=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=HreHvNj6W8lCJitqQAcOFJ/XWQr05sDs5HuQ7X66Vdf3gsUyHKgag3fA4dbfRUa3P VzD1idLDZbHhW7AIY659g+7nJvtfq7baXXVHZ3F2rXF4VVoOwIm9kOkrCPRfqi+/zi vPKY14Gxk0h1tlB+Ejl//3om6d2xMbyc1vVDQHS8= Date: Thu, 23 Sep 2021 16:17:38 -0700 From: Andrew Morton To: Qi Zheng Cc: naoya.horiguchi@nec.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, songmuchun@bytedance.com Subject: Re: [PATCH] mm/memory_failure: Fix the missing pte_unmap() call Message-Id: <20210923161738.990b61933c96df78bc1bf96d@linux-foundation.org> In-Reply-To: <20210923122642.4999-1-zhengqi.arch@bytedance.com> References: <20210923122642.4999-1-zhengqi.arch@bytedance.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 23 Sep 2021 20:26:42 +0800 Qi Zheng wrote: > The paired pte_unmap() call is missing before the > dev_pagemap_mapping_shift() returns. So fix it. > > ... > > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -306,6 +306,7 @@ static unsigned long dev_pagemap_mapping_shift(struct page *page, > struct vm_area_struct *vma) > { > unsigned long address = vma_address(page, vma); > + unsigned long ret = 0; > pgd_t *pgd; > p4d_t *p4d; > pud_t *pud; > @@ -330,10 +331,12 @@ static unsigned long dev_pagemap_mapping_shift(struct page *page, > return PMD_SHIFT; > pte = pte_offset_map(pmd, address); > if (!pte_present(*pte)) > - return 0; > + goto unmap; > if (pte_devmap(*pte)) > - return PAGE_SHIFT; > - return 0; > + ret = PAGE_SHIFT; > +unmap: > + pte_unmap(pte); > + return ret; > } > This is neater? +++ a/mm/memory-failure.c @@ -330,11 +330,8 @@ static unsigned long dev_pagemap_mapping if (pmd_devmap(*pmd)) return PMD_SHIFT; pte = pte_offset_map(pmd, address); - if (!pte_present(*pte)) - goto unmap; - if (pte_devmap(*pte)) + if (pte_present(*pte) && pte_devmap(*pte)) ret = PAGE_SHIFT; -unmap: pte_unmap(pte); return ret; } _