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=-15.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 CAAFAC48BE5 for ; Tue, 15 Jun 2021 10:29:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AC42C61450 for ; Tue, 15 Jun 2021 10:29:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231327AbhFOKbK (ORCPT ); Tue, 15 Jun 2021 06:31:10 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:27921 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231486AbhFOKbJ (ORCPT ); Tue, 15 Jun 2021 06:31:09 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1623752945; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=VhDOgMjiOwt7H+lgbYmC14lLfCiQZ3CWo0eN0+/p/wA=; b=WVj+kV1pNZtXqbgGdGWu0J/brmL1bcVz6Dxlc2jiKzZjPSFvQ7TIgAW9kFhZMtAjdwem94 Cwr2tpoOniWUonudtbAVUmdd+eoVhMqavu7bSw4tgXRlOAK0PP5jaOuVatqNub2KB5rt2C mbBYsE4hzarViWb7+WZCdGV9yI5XARg= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-118-28sqSogFMDmkecx9WwbJyQ-1; Tue, 15 Jun 2021 06:27:59 -0400 X-MC-Unique: 28sqSogFMDmkecx9WwbJyQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 95D6D802575; Tue, 15 Jun 2021 10:27:56 +0000 (UTC) Received: from localhost (ovpn-113-156.ams2.redhat.com [10.36.113.156]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 7FA5A5C1D5; Tue, 15 Jun 2021 10:27:55 +0000 (UTC) From: Cornelia Huck To: Christoph Hellwig , Greg Kroah-Hartman , Jason Gunthorpe , Alex Williamson , Kirti Wankhede Cc: David Airlie , Tony Krowiak , Christian Borntraeger , Jonathan Corbet , Daniel Vetter , dri-devel@lists.freedesktop.org, Vasily Gorbik , Heiko Carstens , intel-gfx@lists.freedesktop.org, Jani Nikula , Jason Herne , Joonas Lahtinen , kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-s390@vger.kernel.org, Halil Pasic , "Rafael J. Wysocki" , Rodrigo Vivi Subject: Re: [PATCH 01/10] driver core: Pull required checks into driver_probe_device() In-Reply-To: <20210614150846.4111871-2-hch@lst.de> Organization: Red Hat GmbH References: <20210614150846.4111871-1-hch@lst.de> <20210614150846.4111871-2-hch@lst.de> User-Agent: Notmuch/0.32.1 (https://notmuchmail.org) Date: Tue, 15 Jun 2021 12:27:53 +0200 Message-ID: <87h7hzxw0m.fsf@redhat.com> MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Mon, Jun 14 2021, Christoph Hellwig wrote: > From: Jason Gunthorpe > > Checking if the dev is dead or if the dev is already bound is a required > precondition to invoking driver_probe_device(). All the call chains > leading here duplicate these checks. > > Add it directly to driver_probe_device() so the precondition is clear and > remove the checks from device_driver_attach() and > __driver_attach_async_helper(). > > The other call chain going through __device_attach_driver() does have > these same checks but they are inlined into logic higher up the call stack > and can't be removed. > > The sysfs uAPI call chain starting at bind_store() is a bit confused > because it reads dev->driver unlocked and returns -ENODEV if it is !NULL, > otherwise it reads it again under lock and returns 0 if it is !NULL. Fix > this to always return -EBUSY and always read dev->driver under its lock. > > Done in preparation for the next patches which will add additional > callers to driver_probe_device() and will need these checks as well. > > Signed-off-by: Jason Gunthorpe > [hch: drop the extra checks in device_driver_attach and bind_store] > Signed-off-by: Christoph Hellwig > --- > drivers/base/bus.c | 2 +- > drivers/base/dd.c | 32 ++++++++++---------------------- > 2 files changed, 11 insertions(+), 23 deletions(-) Reviewed-by: Cornelia Huck