From patchwork Wed Apr 28 21:52:49 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hans de Goede X-Patchwork-Id: 429105 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=-16.0 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=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 C58ACC43461 for ; Wed, 28 Apr 2021 21:53:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 90A136109E for ; Wed, 28 Apr 2021 21:53:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230305AbhD1Vx7 (ORCPT ); Wed, 28 Apr 2021 17:53:59 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:46954 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229942AbhD1Vx7 (ORCPT ); Wed, 28 Apr 2021 17:53:59 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1619646793; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=CHPFfFBaEv5BhiohhcETCsT/UQLEXf89TQ8+clFnID0=; b=MydZZSa/1xbutMQIzvch8SwuKVlsaBQjh0+3zUFWbIsCMz1RcHl+ogjNFxcn+o7msV1afJ +1VPNJR85lrPDjQJqKwUopcDeUqsLEW+CLCYQXPtJ8Hqaj087+NAa8ZEXTL/3w8sYkhFjB 4QRRQY/H3bpZLSQT4A3tgrFG7JZ4TqQ= 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-260-5jHzSbalNpmuGHHKzLbFxw-1; Wed, 28 Apr 2021 17:53:10 -0400 X-MC-Unique: 5jHzSbalNpmuGHHKzLbFxw-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 6C76E803620; Wed, 28 Apr 2021 21:53:08 +0000 (UTC) Received: from x1.localdomain (ovpn-115-166.ams2.redhat.com [10.36.115.166]) by smtp.corp.redhat.com (Postfix) with ESMTP id 862C161D2D; Wed, 28 Apr 2021 21:53:03 +0000 (UTC) From: Hans de Goede To: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Daniel Vetter , David Airlie , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , Greg Kroah-Hartman , Guenter Roeck , Heikki Krogerus Cc: Hans de Goede , intel-gfx , dri-devel@lists.freedesktop.org, platform-driver-x86@vger.kernel.org, linux-usb@vger.kernel.org Subject: [PATCH 1/9] drm/connector: Make the drm_sysfs connector->kdev device hold a reference to the connector Date: Wed, 28 Apr 2021 23:52:49 +0200 Message-Id: <20210428215257.500088-2-hdegoede@redhat.com> In-Reply-To: <20210428215257.500088-1-hdegoede@redhat.com> References: <20210428215257.500088-1-hdegoede@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Userspace could hold open a reference to the connector->kdev device, through e.g. holding a sysfs-atrtribute open after drm_sysfs_connector_remove() has been called. In this case the connector could be free-ed while the connector->kdev device's drvdata is still pointing to it. Give drm_connector devices there own device type, which allows us to specify our own release function and make drm_sysfs_connector_add() take a reference on the connector object, and have the new release function put the reference when the device is released. Giving drm_connector devices there own device type, will also allow checking if a device is a drm_connector device with a "if (device->type == &drm_sysfs_device_connector)" check. Note that the setting of the name member of the device_type struct will cause udev events for drm_connector-s to now contain DEVTYPE=drm_connector as extra info. So this extends the uevent part of the userspace API. Signed-off-by: Hans de Goede --- drivers/gpu/drm/drm_sysfs.c | 54 +++++++++++++++++++++++++++++++------ 1 file changed, 46 insertions(+), 8 deletions(-) diff --git a/drivers/gpu/drm/drm_sysfs.c b/drivers/gpu/drm/drm_sysfs.c index f0336c804639..c344c6d5e738 100644 --- a/drivers/gpu/drm/drm_sysfs.c +++ b/drivers/gpu/drm/drm_sysfs.c @@ -50,6 +50,10 @@ static struct device_type drm_sysfs_device_minor = { .name = "drm_minor" }; +static struct device_type drm_sysfs_device_connector = { + .name = "drm_connector", +}; + struct class *drm_class; static char *drm_devnode(struct device *dev, umode_t *mode) @@ -271,30 +275,64 @@ static const struct attribute_group *connector_dev_groups[] = { NULL }; +static void drm_sysfs_connector_release(struct device *dev) +{ + struct drm_connector *connector = to_drm_connector(dev); + + drm_connector_put(connector); + kfree(dev); +} + int drm_sysfs_connector_add(struct drm_connector *connector) { struct drm_device *dev = connector->dev; + struct device *kdev; + int r; if (connector->kdev) return 0; - connector->kdev = - device_create_with_groups(drm_class, dev->primary->kdev, 0, - connector, connector_dev_groups, - "card%d-%s", dev->primary->index, - connector->name); + kdev = kzalloc(sizeof(*kdev), GFP_KERNEL); + if (!kdev) + return -ENOMEM; + + device_initialize(kdev); + kdev->class = drm_class; + kdev->type = &drm_sysfs_device_connector; + kdev->parent = dev->primary->kdev; + kdev->groups = connector_dev_groups; + kdev->release = drm_sysfs_connector_release; + dev_set_drvdata(kdev, connector); + + r = dev_set_name(kdev, "card%d-%s", dev->primary->index, connector->name); + if (r) + goto err_free; + DRM_DEBUG("adding \"%s\" to sysfs\n", connector->name); - if (IS_ERR(connector->kdev)) { - DRM_ERROR("failed to register connector device: %ld\n", PTR_ERR(connector->kdev)); - return PTR_ERR(connector->kdev); + r = device_add(kdev); + if (r) { + DRM_ERROR("failed to register connector device: %d\n", r); + goto err_free; } + /* + * Ensure the connector object does not get free-ed if userspace still has + * references open to the device through e.g. the connector sysfs-attributes. + */ + drm_connector_get(connector); + + connector->kdev = kdev; + if (connector->ddc) return sysfs_create_link(&connector->kdev->kobj, &connector->ddc->dev.kobj, "ddc"); return 0; + +err_free: + put_device(kdev); + return r; } void drm_sysfs_connector_remove(struct drm_connector *connector)