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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 081C7C43334 for ; Wed, 15 Jun 2022 11:22:41 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5FE3A6B0071; Wed, 15 Jun 2022 07:22:41 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 586E16B0072; Wed, 15 Jun 2022 07:22:41 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 426F56B0073; Wed, 15 Jun 2022 07:22:41 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 300536B0071 for ; Wed, 15 Jun 2022 07:22:41 -0400 (EDT) Received: from smtpin02.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id EBFC434E62 for ; Wed, 15 Jun 2022 11:22:40 +0000 (UTC) X-FDA: 79580232480.02.1B8CE42 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf01.hostedemail.com (Postfix) with ESMTP id 2C0C540007 for ; Wed, 15 Jun 2022 11:22:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Transfer-Encoding :Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=FVOq6VwUFB6uFGq2mjk/V+n5h8ZD55Qbyk92hCokle4=; b=x516N7q+S0IoRntqx03R881c4L aUG+uFkvQ2ZlReI5wNvc3O80OwY0bHH/Osdpk+MWHqf7L63nQRiXo2EB1VMhezaoXeiTgFhHWNt3l yXaJIiZxCiccJ2PMKZxsADdC98aBEj9YWBXFPZlVhenBNO1bd/bYR+0KSgRznX/okKIfkjpW4MF/7 glQ64v59zGHQI2ESvlEk8pPQI4RRfnhRl+ExqjqgtKeaDDVcyWDmBXt/ta8YxblMZuthaANolD81f jIZJiqrZdO0GdFNG68XLUjEfeykpZLcoFEtdcO1rsQzWa6AwI6Z9Gduqytf26S9XofgafjQXlpBoE xTElzBnw==; Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1o1R6Y-00E9Kf-OK; Wed, 15 Jun 2022 11:22:34 +0000 Date: Wed, 15 Jun 2022 04:22:34 -0700 From: Christoph Hellwig To: liubo Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, ying.huang@intel.com, willy@infradead.org, vbabka@suse.cz, surenb@google.com, peterx@redhat.com, neilb@suse.de, naoya.horiguchi@nec.com, minchan@kernel.org, linmiaohe@huawei.com, louhongxiang@huawei.com, linfeilong@huawei.com Subject: Re: [PATCH v2 2/2] mm/swapfile: release swap info when swap device is unpluged Message-ID: References: <20220615070228.2858170-1-liubo254@huawei.com> <20220615070228.2858170-3-liubo254@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20220615070228.2858170-3-liubo254@huawei.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1655292160; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=FVOq6VwUFB6uFGq2mjk/V+n5h8ZD55Qbyk92hCokle4=; b=kwBHzatbPjouIo+/N4A64La/vYG5xaNIkuObNWf/pxRT5nINqX/w26Thcny9ElJi2jZafB LEBAo0CeslykjVD49RKVfri5alE4/6/uTlRKrFjhpHrJVnYux7/+J8v7drg2yIRPrdRVjb xAmCOOg4U7vXRi1tdWpvEjljHPsw1aQ= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=pass header.d=infradead.org header.s=bombadil.20210309 header.b=x516N7q+; spf=none (imf01.hostedemail.com: domain of BATV+cd04db8a85bff7cd13dc+6870+infradead.org+hch@bombadil.srs.infradead.org has no SPF policy when checking 198.137.202.133) smtp.mailfrom=BATV+cd04db8a85bff7cd13dc+6870+infradead.org+hch@bombadil.srs.infradead.org; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1655292160; a=rsa-sha256; cv=none; b=vSCi2Eoi20XHf5SBYT3IWMU++qQnROiFfFp2zGtsX0nyujhLKHYyNNXXvZ2akMQqcOZqyK BMA9/luePSxtvvq94M5uSzMh68QtyQE7aZg7F1TjIYSfxzlKzwiIVlrqAwE5XOhlLk+63k HJp/MTDKDA9ur2XPYVLekWU1m+lFPnI= X-Stat-Signature: cccgfmi1cp6wafdmjn3a4kirc4r4e6y1 X-Rspamd-Queue-Id: 2C0C540007 X-Rspamd-Server: rspam11 X-Rspam-User: Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=infradead.org header.s=bombadil.20210309 header.b=x516N7q+; spf=none (imf01.hostedemail.com: domain of BATV+cd04db8a85bff7cd13dc+6870+infradead.org+hch@bombadil.srs.infradead.org has no SPF policy when checking 198.137.202.133) smtp.mailfrom=BATV+cd04db8a85bff7cd13dc+6870+infradead.org+hch@bombadil.srs.infradead.org; dmarc=none X-HE-Tag: 1655292160-717961 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: Sorry, but this is simply broken. We can't just do d_path magic here. That being said the problem is real, and I think the right answer is to offer a swapoff variant that doesn't need to open the underlying device or file, but useѕ some kind of handle. I'm just not sure what would be a good handle here.