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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 8D32CC43331 for ; Wed, 25 Mar 2020 11:20:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6BA422077D for ; Wed, 25 Mar 2020 11:20:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727158AbgCYLUv (ORCPT ); Wed, 25 Mar 2020 07:20:51 -0400 Received: from relay5-d.mail.gandi.net ([217.70.183.197]:55631 "EHLO relay5-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726262AbgCYLUu (ORCPT ); Wed, 25 Mar 2020 07:20:50 -0400 X-Originating-IP: 2.224.242.101 Received: from uno.localdomain (2-224-242-101.ip172.fastwebnet.it [2.224.242.101]) (Authenticated sender: jacopo@jmondi.org) by relay5-d.mail.gandi.net (Postfix) with ESMTPSA id 302ED1C0010; Wed, 25 Mar 2020 11:20:43 +0000 (UTC) Date: Wed, 25 Mar 2020 12:23:42 +0100 From: Jacopo Mondi To: Andrey Konovalov Cc: linux-media@vger.kernel.org, libcamera-devel@lists.libcamera.org, hverkuil-cisco@xs4all.nl, mchehab@kernel.org, sakari.ailus@linux.intel.com Subject: Re: [libcamera-devel] [PATCH 2/4] media: v4l2-dev: Add v4l2_device_register_ro_subdev_node() Message-ID: <20200325112342.andqi2uognizd4uq@uno.localdomain> References: <20200324202844.1518292-1-jacopo@jmondi.org> <20200324202844.1518292-3-jacopo@jmondi.org> <313fcb7e-6612-9cf5-a4eb-ba6edb39f754@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <313fcb7e-6612-9cf5-a4eb-ba6edb39f754@linaro.org> Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Hi Andrey, thanks for the review On Wed, Mar 25, 2020 at 11:42:27AM +0300, Andrey Konovalov wrote: > Hi Jacopo, > > Thank you for your patch set! > > On 24.03.2020 23:28, Jacopo Mondi wrote: > > Add to the V4L2 code a function to register device nodes for video > > subdevices in read-only mode. > > > > Registering a device node in read-only mode is useful to expose to > > userspace the current sub-device configuration, without allowing > > application to change it by using the V4L2 subdevice ioctls. > > > > Signed-off-by: Jacopo Mondi > > --- > > drivers/media/v4l2-core/v4l2-device.c | 16 +++++++++++++++- > > drivers/media/v4l2-core/v4l2-subdev.c | 19 +++++++++++++++++++ > > include/media/v4l2-dev.h | 7 +++++++ > > include/media/v4l2-device.h | 10 ++++++++++ > > 4 files changed, 51 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/media/v4l2-core/v4l2-device.c b/drivers/media/v4l2-core/v4l2-device.c > > index 63d6b147b21e..6f9dba36eda1 100644 > > --- a/drivers/media/v4l2-core/v4l2-device.c > > +++ b/drivers/media/v4l2-core/v4l2-device.c > > @@ -188,7 +188,8 @@ static void v4l2_device_release_subdev_node(struct video_device *vdev) > > kfree(vdev); > > } > > -int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev) > > +int __v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev, > > + bool read_only) > > { > > struct video_device *vdev; > > struct v4l2_subdev *sd; > > @@ -217,6 +218,8 @@ int v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev) > > vdev->fops = &v4l2_subdev_fops; > > vdev->release = v4l2_device_release_subdev_node; > > vdev->ctrl_handler = sd->ctrl_handler; > > + if (read_only) > > + vdev->flags |= V4L2_FL_RO_DEVNODE; > > > > > @@ -331,6 +331,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg) > > struct v4l2_fh *vfh = file->private_data; > > #if defined(CONFIG_VIDEO_V4L2_SUBDEV_API) > > struct v4l2_subdev_fh *subdev_fh = to_v4l2_subdev_fh(vfh); > > + bool ro_devnode = !!(vdev->flags & V4L2_FL_RO_DEVNODE); > > So V4L2_FL_RO_DEVNODE is a bit mask, ... > > > > > diff --git a/include/media/v4l2-dev.h b/include/media/v4l2-dev.h > > index 48531e57cc5a..029873a338f2 100644 > > --- a/include/media/v4l2-dev.h > > +++ b/include/media/v4l2-dev.h > > @@ -82,11 +82,18 @@ struct v4l2_ctrl_handler; > > * but the old crop API will still work as expected in order to preserve > > * backwards compatibility. > > * Never set this flag for new drivers. > > + * @V4L2_FL_RO_DEVNODE: > > + * indicates that the video device node is registered in read-only mode. > > + * The flag only applies to device nodes registered for sub-devices, it is > > + * set by the core when the sub-devices device nodes are registered with > > + * v4l2_device_register_ro_subdev_nodes() and used by the sub-device ioctl > > + * handler to restrict access to some ioctl calls. > > */ > > enum v4l2_video_device_flags { > > V4L2_FL_REGISTERED = 0, > > V4L2_FL_USES_V4L2_FH = 1, > > V4L2_FL_QUIRK_INVERTED_CROP = 2, > > + V4L2_FL_RO_DEVNODE = 3, > > ... then V4L2_FL_RO_DEVNODE should rather be equal to 4, than to (V4L2_FL_USES_V4L2_FH | V4L2_FL_QUIRK_INVERTED_CROP) Ups! I should have noticed looking at V4L2_FL_REGISTERED=0 that these flags are actually meant to be used as bit shifts. I can't say I like the idea, but I should have known better than this. I'll resend using set_bit() and test_bit(). Thanks for your help! > > Thanks, > Andrey > > > }; > > /* Priority helper functions */ > > diff --git a/include/media/v4l2-device.h b/include/media/v4l2-device.h > > index e0b8f2602670..0df667ba9938 100644 > > --- a/include/media/v4l2-device.h > > +++ b/include/media/v4l2-device.h > > @@ -183,6 +183,16 @@ void v4l2_device_unregister_subdev(struct v4l2_subdev *sd); > > int __must_check > > v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev); > > +/** > > + * v4l2_device_register_ro_subdev_nodes - Registers read-only device nodes for > > + * all subdevs of the v4l2 device that are marked with the > > + * %V4L2_SUBDEV_FL_HAS_DEVNODE flag. > > + * > > + * @v4l2_dev: pointer to struct v4l2_device > > + */ > > +int __must_check > > +v4l2_device_register_ro_subdev_nodes(struct v4l2_device *v4l2_dev); > > + > > /** > > * v4l2_subdev_notify - Sends a notification to v4l2_device. > > * > >