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=-2.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,PDS_BAD_THREAD_QP_64, SPF_HELO_NONE,SPF_PASS autolearn=no 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 E3F6BC433DB for ; Thu, 21 Jan 2021 17:47:29 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id F1DB122B2B for ; Thu, 21 Jan 2021 17:47:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F1DB122B2B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=ACULAB.COM Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 4DM8wt60sjzDrV2 for ; Fri, 22 Jan 2021 04:47:26 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=aculab.com (client-ip=185.58.86.151; helo=eu-smtp-delivery-151.mimecast.com; envelope-from=david.laight@aculab.com; receiver=) Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [185.58.86.151]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4DM8tD3rbmzDqQ3 for ; Fri, 22 Jan 2021 04:45:06 +1100 (AEDT) Received: from AcuMS.aculab.com (156.67.243.126 [156.67.243.126]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-7-70jJZbebO02FvmwaO8iuwQ-1; Thu, 21 Jan 2021 17:44:57 +0000 X-MC-Unique: 70jJZbebO02FvmwaO8iuwQ-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) by AcuMS.aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Thu, 21 Jan 2021 17:44:55 +0000 Received: from AcuMS.Aculab.com ([fe80::43c:695e:880f:8750]) by AcuMS.aculab.com ([fe80::43c:695e:880f:8750%12]) with mapi id 15.00.1347.000; Thu, 21 Jan 2021 17:44:55 +0000 From: David Laight To: 'Christoph Hellwig' , Christophe Leroy Subject: RE: [PATCH 02/13] module: add a module_loaded helper Thread-Topic: [PATCH 02/13] module: add a module_loaded helper Thread-Index: AQHW8BhvE0+Qt/OaHkK/jwqI2nu4BKoyViXg Date: Thu, 21 Jan 2021 17:44:55 +0000 Message-ID: <8d59f11971764db2a104c87937e1d3ab@AcuMS.aculab.com> References: <20210121074959.313333-1-hch@lst.de> <20210121074959.313333-3-hch@lst.de> <844a7fc3-2cba-46d2-fd4e-e5fe16b08573@csgroup.eu> <20210121171119.GA29916@lst.de> In-Reply-To: <20210121171119.GA29916@lst.de> Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=C51A453 smtp.mailfrom=david.laight@aculab.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Petr Mladek , Michal Marek , Andrew Donnellan , Jessica Yu , "linux-kbuild@vger.kernel.org" , David Airlie , Masahiro Yamada , Jiri Kosina , Maarten Lankhorst , "linux-kernel@vger.kernel.org" , Maxime Ripard , Joe Lawrence , "dri-devel@lists.freedesktop.org" , Thomas Zimmermann , Josh Poimboeuf , Frederic Barrat , "live-patching@vger.kernel.org" , Daniel Vetter , Miroslav Benes , "linuxppc-dev@lists.ozlabs.org" Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" >=20 > On Thu, Jan 21, 2021 at 11:00:20AM +0100, Christophe Leroy wrote: > > > +bool module_loaded(const char *name); > > > > Maybe module_is_loaded() would be a better name. >=20 > Fine with me. It does look like both callers aren't 'unsafe'. But it is a bit strange returning a stale value. It did make be look a bit more deeply at try_module_get(). For THIS_MODULE (eg to get an extra reference for a kthread) I doubt it can ever fail. But the other cases require a 'module' structure be passed in. ISTM that unloading the module could invalidate the pointer that has just been read from some other structure. I'm guessing that some other lock must always be held. =09David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1= PT, UK Registration No: 1397386 (Wales)