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a="184724506" X-IronPort-AV: E=Sophos;i="5.81,233,1610438400"; d="scan'208";a="184724506" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Mar 2021 10:54:04 -0800 IronPort-SDR: DAukqgs/k/S1fw6lyM65c88NQwWMEYELuHbUA4ffTZ75YDCRt59nM5t8XwGCszEf5RKjgBTPl2 8TtcKU7F8JBw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.81,233,1610438400"; d="scan'208";a="408333310" Received: from fmsmsx601.amr.corp.intel.com ([10.18.126.81]) by orsmga007.jf.intel.com with ESMTP; 08 Mar 2021 10:54:03 -0800 Received: from fmsmsx612.amr.corp.intel.com (10.18.126.92) by fmsmsx601.amr.corp.intel.com (10.18.126.81) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2106.2; Mon, 8 Mar 2021 10:54:03 -0800 Received: from fmsmsx610.amr.corp.intel.com (10.18.126.90) by fmsmsx612.amr.corp.intel.com (10.18.126.92) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2106.2; Mon, 8 Mar 2021 10:54:03 -0800 Received: from fmsmsx610.amr.corp.intel.com ([10.18.126.90]) by fmsmsx610.amr.corp.intel.com ([10.18.126.90]) with mapi id 15.01.2106.013; Mon, 8 Mar 2021 10:54:03 -0800 From: "Luck, Tony" To: =?iso-2022-jp?B?SE9SSUdVQ0hJIE5BT1lBKBskQktZOH0hIUQ+TGkbKEIp?= CC: Aili Yao , Oscar Salvador , "david@redhat.com" , "akpm@linux-foundation.org" , "bp@alien8.de" , "tglx@linutronix.de" , "mingo@redhat.com" , "hpa@zytor.com" , "x86@kernel.org" , "linux-edac@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "yangfeng1@kingsoft.com" Subject: RE: [PATCH] mm,hwpoison: return -EBUSY when page already poisoned Thread-Topic: [PATCH] mm,hwpoison: return -EBUSY when page already poisoned Thread-Index: AQHXCnz5ja9ELypBUEatGW66U99st6pnoa2AgAEgN4CAAIHfAIAAAyEAgAAQXwD//9g7gIABDSmAgAALNoCAB2DqAIAAiu0AgABOzQD//+3L0IABObiAgAAiT4CAACi3AIAAmjmAgACgEACAAAHdAIAA0uUAgAQ6cQCAAESgQA== Date: Mon, 8 Mar 2021 18:54:02 +0000 Message-ID: <3690ece2101d428fb9067fcd2a423ff8@intel.com> References: <20210303115710.2e9f8e23@alex-virtual-machine> <20210303163912.3d508e0f@alex-virtual-machine> <1a78e9abdc134e35a5efcbf6b2fd2263@intel.com> <20210304101653.546a9da1@alex-virtual-machine> <20210304121941.667047c3@alex-virtual-machine> <20210304144524.795872d7@alex-virtual-machine> <20210304235720.GA215567@agluck-desk2.amr.corp.intel.com> <20210305093016.40c87375@alex-virtual-machine> <20210305093656.6c262b19@alex-virtual-machine> <20210305221143.GA220893@agluck-desk2.amr.corp.intel.com> <20210308064558.GA3617@hori.linux.bs1.fc.nec.co.jp> In-Reply-To: <20210308064558.GA3617@hori.linux.bs1.fc.nec.co.jp> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: dlp-product: dlpe-windows dlp-reaction: no-action dlp-version: 11.5.1.3 x-originating-ip: [10.1.200.100] Content-Type: text/plain; charset="iso-2022-jp" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 545BBC0007C1 X-Stat-Signature: 8ggyjukooznwphofu5x7mg5wmyoxqc74 Received-SPF: none (intel.com>: No applicable sender policy available) receiver=imf22; identity=mailfrom; envelope-from=""; helo=mga11.intel.com; client-ip=192.55.52.93 X-HE-DKIM-Result: none/none X-HE-Tag: 1615229644-99734 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: >> So it should be safe to grab and hold a mutex. See patch below. > > The mutex approach looks simpler and safer, so I'm fine with it. Thanks. Is that an "Acked-by:"? >> /** >> * memory_failure - Handle memory failure of a page. >> * @pfn: Page Number of the corrupted page >> @@ -1424,12 +1426,18 @@ int memory_failure(unsigned long pfn, int flags) >> return -ENXIO; >> } >> =20 >> + mutex_lock(&mf_mutex); > > Is it better to take mutex before memory_failure_dev_pagemap() block? > Or we don't have to protect against race for device memory? No races (recovery is only attempted for errors in normal memory). -Tony