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=-13.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 6BDD8C433ED for ; Tue, 13 Apr 2021 01:33:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 414706128A for ; Tue, 13 Apr 2021 01:33:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245212AbhDMBeM (ORCPT ); Mon, 12 Apr 2021 21:34:12 -0400 Received: from mga06.intel.com ([134.134.136.31]:12986 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240410AbhDMBeG (ORCPT ); Mon, 12 Apr 2021 21:34:06 -0400 IronPort-SDR: xriSWE7X+l81K39k/JdOQdTrIypVQtJJwqHl7DCknnb8tC78ih3qmtDrM+RJ7n7xCJx8gM9Xew 86TUuxCpwhGw== X-IronPort-AV: E=McAfee;i="6200,9189,9952"; a="255638438" X-IronPort-AV: E=Sophos;i="5.82,216,1613462400"; d="scan'208";a="255638438" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Apr 2021 18:33:46 -0700 IronPort-SDR: V+KbEoJUqwsneLAH9VH89rfVsf/Uhl9NaAxRjjUEWOfN0vy1NAvE2WdOJLzodsBna4aeGc5PvU P/F7QieILvaQ== X-IronPort-AV: E=Sophos;i="5.82,216,1613462400"; d="scan'208";a="424042790" Received: from yhuang6-desk1.sh.intel.com (HELO yhuang6-desk1.ccr.corp.intel.com) ([10.239.13.1]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Apr 2021 18:33:43 -0700 From: "Huang, Ying" To: Miaohe Lin Cc: , , , , , , , , , , , , Subject: Re: [PATCH 3/5] mm/swap_state: fix get_shadow_from_swap_cache() race with swapoff References: <20210408130820.48233-1-linmiaohe@huawei.com> <20210408130820.48233-4-linmiaohe@huawei.com> Date: Tue, 13 Apr 2021 09:33:41 +0800 In-Reply-To: <20210408130820.48233-4-linmiaohe@huawei.com> (Miaohe Lin's message of "Thu, 8 Apr 2021 09:08:18 -0400") Message-ID: <87im4rufwq.fsf@yhuang6-desk1.ccr.corp.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Miaohe Lin writes: > The function get_shadow_from_swap_cache() can race with swapoff, though > it's only called by do_swap_page() now. > > Fixes: aae466b0052e ("mm/swap: implement workingset detection for anonymous LRU") > Signed-off-by: Miaohe Lin This is unnecessary. The only caller has guaranteed the swap device from swapoff. Best Regards, Huang, Ying > --- > mm/swap_state.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/mm/swap_state.c b/mm/swap_state.c > index 272ea2108c9d..709c260d644a 100644 > --- a/mm/swap_state.c > +++ b/mm/swap_state.c > @@ -83,11 +83,14 @@ void show_swap_cache_info(void) > > void *get_shadow_from_swap_cache(swp_entry_t entry) > { > - struct address_space *address_space = swap_address_space(entry); > - pgoff_t idx = swp_offset(entry); > + struct swap_info_struct *si; > struct page *page; > > - page = xa_load(&address_space->i_pages, idx); > + si = get_swap_device(entry); > + if (!si) > + return NULL; > + page = xa_load(&swap_address_space(entry)->i_pages, swp_offset(entry)); > + put_swap_device(si); > if (xa_is_value(page)) > return page; > return NULL; 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=-13.7 required=3.0 tests=BAYES_00, 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 68FBFC433B4 for ; Tue, 13 Apr 2021 01:33:56 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id EC3836128A for ; Tue, 13 Apr 2021 01:33:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EC3836128A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 7D7A56B0036; Mon, 12 Apr 2021 21:33:55 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 79B2C6B006E; Mon, 12 Apr 2021 21:33:55 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 663016B0070; Mon, 12 Apr 2021 21:33:55 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0063.hostedemail.com [216.40.44.63]) by kanga.kvack.org (Postfix) with ESMTP id 497196B0036 for ; Mon, 12 Apr 2021 21:33:55 -0400 (EDT) Received: from smtpin07.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 08D3C815B for ; Tue, 13 Apr 2021 01:33:55 +0000 (UTC) X-FDA: 78025622430.07.EE4F60B Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by imf29.hostedemail.com (Postfix) with ESMTP id 834D8D6 for ; Tue, 13 Apr 2021 01:33:51 +0000 (UTC) IronPort-SDR: sJP374qaeu+vdShs2LL6REZ0Oeqit5tnBS3nG1Xm9OWZNCtf5KCJOGDwLm//bAktPzCWfHuEXg 8bxRwvn2/1eQ== X-IronPort-AV: E=McAfee;i="6200,9189,9952"; a="174413189" X-IronPort-AV: E=Sophos;i="5.82,216,1613462400"; d="scan'208";a="174413189" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Apr 2021 18:33:46 -0700 IronPort-SDR: V+KbEoJUqwsneLAH9VH89rfVsf/Uhl9NaAxRjjUEWOfN0vy1NAvE2WdOJLzodsBna4aeGc5PvU P/F7QieILvaQ== X-IronPort-AV: E=Sophos;i="5.82,216,1613462400"; d="scan'208";a="424042790" Received: from yhuang6-desk1.sh.intel.com (HELO yhuang6-desk1.ccr.corp.intel.com) ([10.239.13.1]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Apr 2021 18:33:43 -0700 From: "Huang, Ying" To: Miaohe Lin Cc: , , , , , , , , , , , , Subject: Re: [PATCH 3/5] mm/swap_state: fix get_shadow_from_swap_cache() race with swapoff References: <20210408130820.48233-1-linmiaohe@huawei.com> <20210408130820.48233-4-linmiaohe@huawei.com> Date: Tue, 13 Apr 2021 09:33:41 +0800 In-Reply-To: <20210408130820.48233-4-linmiaohe@huawei.com> (Miaohe Lin's message of "Thu, 8 Apr 2021 09:08:18 -0400") Message-ID: <87im4rufwq.fsf@yhuang6-desk1.ccr.corp.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii X-Rspamd-Queue-Id: 834D8D6 X-Stat-Signature: mpk6y6o8z5t9hwwqss5u5uai8rd9foke X-Rspamd-Server: rspam02 Received-SPF: none (intel.com>: No applicable sender policy available) receiver=imf29; identity=mailfrom; envelope-from=""; helo=mga17.intel.com; client-ip=192.55.52.151 X-HE-DKIM-Result: none/none X-HE-Tag: 1618277631-491242 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: Miaohe Lin writes: > The function get_shadow_from_swap_cache() can race with swapoff, though > it's only called by do_swap_page() now. > > Fixes: aae466b0052e ("mm/swap: implement workingset detection for anonymous LRU") > Signed-off-by: Miaohe Lin This is unnecessary. The only caller has guaranteed the swap device from swapoff. Best Regards, Huang, Ying > --- > mm/swap_state.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/mm/swap_state.c b/mm/swap_state.c > index 272ea2108c9d..709c260d644a 100644 > --- a/mm/swap_state.c > +++ b/mm/swap_state.c > @@ -83,11 +83,14 @@ void show_swap_cache_info(void) > > void *get_shadow_from_swap_cache(swp_entry_t entry) > { > - struct address_space *address_space = swap_address_space(entry); > - pgoff_t idx = swp_offset(entry); > + struct swap_info_struct *si; > struct page *page; > > - page = xa_load(&address_space->i_pages, idx); > + si = get_swap_device(entry); > + if (!si) > + return NULL; > + page = xa_load(&swap_address_space(entry)->i_pages, swp_offset(entry)); > + put_swap_device(si); > if (xa_is_value(page)) > return page; > return NULL;