From patchwork Fri Aug 20 02:04:05 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 12448223 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=-15.8 required=3.0 tests=BAYES_00,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 69D99C432BE for ; Fri, 20 Aug 2021 02:04:09 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id F14BB610FF for ; Fri, 20 Aug 2021 02:04:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org F14BB610FF Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 780E6900002; Thu, 19 Aug 2021 22:04:08 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 730C86B0072; Thu, 19 Aug 2021 22:04:08 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 646F9900002; Thu, 19 Aug 2021 22:04:08 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0095.hostedemail.com [216.40.44.95]) by kanga.kvack.org (Postfix) with ESMTP id 49F816B0071 for ; Thu, 19 Aug 2021 22:04:08 -0400 (EDT) Received: from smtpin09.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id D352A80AEBFD for ; Fri, 20 Aug 2021 02:04:07 +0000 (UTC) X-FDA: 78493813734.09.B087A01 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf24.hostedemail.com (Postfix) with ESMTP id 91273B0000A2 for ; Fri, 20 Aug 2021 02:04:07 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 3DE9E610F9; Fri, 20 Aug 2021 02:04:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1629425046; bh=PWdV/TbRsGAPneOvUthjB3oRGQkw80mr2U70HDbRc1g=; h=Date:From:To:Subject:In-Reply-To:From; b=uFt0Hp0FX/hYIZTV7rMPH0HCaRU9ulNtRS7NmhjvFkNZXBgeBILnqC34OeISi25ht sV4a6qCH4WXGk5eilch6aLV8dt0GXv0x52DxsGTadTmEc9DFfKKqov23a/VzcguZSJ 7bWyhnnJ4HDYu4XQj5BqeS3SMvSEVKAC3ARzSUvo= Date: Thu, 19 Aug 2021 19:04:05 -0700 From: Andrew Morton To: akpm@linux-foundation.org, david@redhat.com, hannes@cmpxchg.org, hughd@google.com, iamjoonsoo.kim@lge.com, linmiaohe@huawei.com, linux-mm@kvack.org, mhocko@suse.com, minchan@kernel.org, mm-commits@vger.kernel.org, shy828301@gmail.com, torvalds@linux-foundation.org, willy@infradead.org, ying.huang@intel.com Subject: [patch 01/10] Revert "mm/shmem: fix shmem_swapin() race with swapoff" Message-ID: <20210820020405.w2NSFTd1-%akpm@linux-foundation.org> In-Reply-To: <20210819190327.14fc4e97102e1af7929e30af@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Rspamd-Queue-Id: 91273B0000A2 Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=uFt0Hp0F; dmarc=none; spf=pass (imf24.hostedemail.com: domain of akpm@linux-foundation.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org X-Rspamd-Server: rspam04 X-Stat-Signature: b1zdkbpdcb4t5g6xrq77oubu6fqbuwo7 X-HE-Tag: 1629425047-870817 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: From: Yang Shi Subject: Revert "mm/shmem: fix shmem_swapin() race with swapoff" Due to the change about how block layer detects congestion the justification of commit 8fd2e0b505d1 ("mm: swap: check if swap backing device is congested or not") doesn't stand anymore, so the commit could be just reverted in order to solve the race reported by commit 2efa33fc7f6e ("mm/shmem: fix shmem_swapin() race with swapoff"), so the fix commit could be just reverted as well. And that fix is also kind of buggy as discussed by [1] and [2]. [1] https://lore.kernel.org/linux-mm/24187e5e-069-9f3f-cefe-39ac70783753@google.com/ [2] https://lore.kernel.org/linux-mm/e82380b9-3ad4-4a52-be50-6d45c7f2b5da@google.com/ Link: https://lkml.kernel.org/r/20210810202936.2672-2-shy828301@gmail.com Signed-off-by: Yang Shi Suggested-by: Hugh Dickins Acked-by: Hugh Dickins Cc: "Huang, Ying" Cc: Miaohe Lin Cc: David Hildenbrand Cc: Johannes Weiner Cc: Joonsoo Kim Cc: Matthew Wilcox (Oracle) Cc: Michal Hocko Cc: Minchan Kim Signed-off-by: Andrew Morton --- mm/shmem.c | 14 +------------- 1 file changed, 1 insertion(+), 13 deletions(-) --- a/mm/shmem.c~revert-mm-shmem-fix-shmem_swapin-race-with-swapoff +++ a/mm/shmem.c @@ -1696,8 +1696,7 @@ static int shmem_swapin_page(struct inod struct address_space *mapping = inode->i_mapping; struct shmem_inode_info *info = SHMEM_I(inode); struct mm_struct *charge_mm = vma ? vma->vm_mm : NULL; - struct swap_info_struct *si; - struct page *page = NULL; + struct page *page; swp_entry_t swap; int error; @@ -1705,12 +1704,6 @@ static int shmem_swapin_page(struct inod swap = radix_to_swp_entry(*pagep); *pagep = NULL; - /* Prevent swapoff from happening to us. */ - si = get_swap_device(swap); - if (!si) { - error = EINVAL; - goto failed; - } /* Look it up and read it in.. */ page = lookup_swap_cache(swap, NULL, 0); if (!page) { @@ -1772,8 +1765,6 @@ static int shmem_swapin_page(struct inod swap_free(swap); *pagep = page; - if (si) - put_swap_device(si); return 0; failed: if (!shmem_confirm_swap(mapping, index, swap)) @@ -1784,9 +1775,6 @@ unlock: put_page(page); } - if (si) - put_swap_device(si); - return error; }