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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B0320C433FE for ; Sun, 3 Oct 2021 20:14:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 88DBB6121F for ; Sun, 3 Oct 2021 20:14:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231610AbhJCUQD (ORCPT ); Sun, 3 Oct 2021 16:16:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58714 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231597AbhJCUQC (ORCPT ); Sun, 3 Oct 2021 16:16:02 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1F017C0613EC for ; Sun, 3 Oct 2021 13:14:14 -0700 (PDT) Received: from dude.hi.pengutronix.de ([2001:67c:670:100:1d::7]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1mX7s8-0002EY-0z; Sun, 03 Oct 2021 22:14:08 +0200 Received: from mgr by dude.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1mX7s6-0006HS-Cr; Sun, 03 Oct 2021 22:14:06 +0200 From: Michael Grzeschik To: laurent.pinchart@ideasonboard.com Cc: linux-usb@vger.kernel.org, balbi@kernel.org, hverkuil@xs4all.nl, gregkh@linuxfoundation.org, m.tretter@pengutronix.de, linux-media@vger.kernel.org Subject: [RESEND PATCH v4] usb: gadget: uvc: fix multiple opens Date: Sun, 3 Oct 2021 22:13:55 +0200 Message-Id: <20211003201355.24081-1-m.grzeschik@pengutronix.de> X-Mailer: git-send-email 2.30.2 In-Reply-To: <87pn261h4c.fsf@kernel.org> References: <87pn261h4c.fsf@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::7 X-SA-Exim-Mail-From: mgr@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-media@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org From: Thomas Haemmerle Currently, the UVC function is activated when open on the corresponding v4l2 device is called. On another open the activation of the function fails since the deactivation counter in `usb_function_activate` equals 0. However the error is not returned to userspace since the open of the v4l2 device is successful. On a close the function is deactivated (since deactivation counter still equals 0) and the video is disabled in `uvc_v4l2_release`, although the UVC application potentially is streaming. Move activation of UVC function to subscription on UVC_EVENT_SETUP because there we can guarantee for a userspace application utilizing UVC. Block subscription on UVC_EVENT_SETUP while another application already is subscribed to it, indicated by `bool func_connected` in `struct uvc_device`. Extend the `struct uvc_file_handle` with member `bool is_uvc_app_handle` to tag it as the handle used by the userspace UVC application. With this a process is able to check capabilities of the v4l2 device without deactivating the function for the actual UVC application. Reviewed-By: Michael Tretter Signed-off-by: Thomas Haemmerle Signed-off-by: Michael Tretter Signed-off-by: Michael Grzeschik --- v4: - remove unnecessary inner parentheses - keep and use the local video variable in `uvc_v4l2_release()` v3: - replace `unsigned int connections` with `bool func_connected` - rename `bool connected` to `bool is_uvc_app_handle` v2: - fix deadlock in `uvc_v4l2_unsubscribe_event()` (mutex is already locked in v4l2-core) introduced in v1 - lock mutex in `uvc_v4l2_release()` to suppress ioctls and protect connected --- drivers/usb/gadget/function/uvc.h | 2 ++ drivers/usb/gadget/function/uvc_v4l2.c | 49 ++++++++++++++++++++++---- 2 files changed, 44 insertions(+), 7 deletions(-) diff --git a/drivers/usb/gadget/function/uvc.h b/drivers/usb/gadget/function/uvc.h index 255a61bd6a6a8..9d5f17b551bbd 100644 --- a/drivers/usb/gadget/function/uvc.h +++ b/drivers/usb/gadget/function/uvc.h @@ -126,6 +126,7 @@ struct uvc_device { enum uvc_state state; struct usb_function func; struct uvc_video video; + bool func_connected; /* Descriptors */ struct { @@ -156,6 +157,7 @@ static inline struct uvc_device *to_uvc(struct usb_function *f) struct uvc_file_handle { struct v4l2_fh vfh; struct uvc_video *device; + bool is_uvc_app_handle; }; #define to_uvc_file_handle(handle) \ diff --git a/drivers/usb/gadget/function/uvc_v4l2.c b/drivers/usb/gadget/function/uvc_v4l2.c index 4ca89eab61590..197c26f7aec63 100644 --- a/drivers/usb/gadget/function/uvc_v4l2.c +++ b/drivers/usb/gadget/function/uvc_v4l2.c @@ -227,17 +227,55 @@ static int uvc_v4l2_subscribe_event(struct v4l2_fh *fh, const struct v4l2_event_subscription *sub) { + struct uvc_device *uvc = video_get_drvdata(fh->vdev); + struct uvc_file_handle *handle = to_uvc_file_handle(fh); + int ret; + if (sub->type < UVC_EVENT_FIRST || sub->type > UVC_EVENT_LAST) return -EINVAL; - return v4l2_event_subscribe(fh, sub, 2, NULL); + if (sub->type == UVC_EVENT_SETUP && uvc->func_connected) + return -EBUSY; + + ret = v4l2_event_subscribe(fh, sub, 2, NULL); + if (ret < 0) + return ret; + + if (sub->type == UVC_EVENT_SETUP) { + uvc->func_connected = true; + handle->is_uvc_app_handle = true; + uvc_function_connect(uvc); + } + + return 0; +} + +static void uvc_v4l2_disable(struct uvc_device *uvc) +{ + uvc->func_connected = false; + uvc_function_disconnect(uvc); + uvcg_video_enable(&uvc->video, 0); + uvcg_free_buffers(&uvc->video.queue); } static int uvc_v4l2_unsubscribe_event(struct v4l2_fh *fh, const struct v4l2_event_subscription *sub) { - return v4l2_event_unsubscribe(fh, sub); + struct uvc_device *uvc = video_get_drvdata(fh->vdev); + struct uvc_file_handle *handle = to_uvc_file_handle(fh); + int ret; + + ret = v4l2_event_unsubscribe(fh, sub); + if (ret < 0) + return ret; + + if (sub->type == UVC_EVENT_SETUP && handle->is_uvc_app_handle) { + uvc_v4l2_disable(uvc); + handle->is_uvc_app_handle = false; + } + + return 0; } static long @@ -292,7 +330,6 @@ uvc_v4l2_open(struct file *file) handle->device = &uvc->video; file->private_data = &handle->vfh; - uvc_function_connect(uvc); return 0; } @@ -304,11 +341,9 @@ uvc_v4l2_release(struct file *file) struct uvc_file_handle *handle = to_uvc_file_handle(file->private_data); struct uvc_video *video = handle->device; - uvc_function_disconnect(uvc); - mutex_lock(&video->mutex); - uvcg_video_enable(video, 0); - uvcg_free_buffers(&video->queue); + if (handle->is_uvc_app_handle) + uvc_v4l2_disable(uvc); mutex_unlock(&video->mutex); file->private_data = NULL; -- 2.30.2