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=-13.8 required=3.0 tests=BAYES_00, 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 77397C4320E for ; Thu, 2 Sep 2021 12:19:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5FBE561059 for ; Thu, 2 Sep 2021 12:19:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344125AbhIBMU0 convert rfc822-to-8bit (ORCPT ); Thu, 2 Sep 2021 08:20:26 -0400 Received: from mx20.baidu.com ([111.202.115.85]:60146 "EHLO baidu.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S234098AbhIBMUY (ORCPT ); Thu, 2 Sep 2021 08:20:24 -0400 Received: from BC-Mail-Ex25.internal.baidu.com (unknown [172.31.51.19]) by Forcepoint Email with ESMTPS id 0F222B22C10458F716F9; Thu, 2 Sep 2021 20:19:23 +0800 (CST) Received: from BJHW-MAIL-EX27.internal.baidu.com (10.127.64.42) by BC-Mail-Ex25.internal.baidu.com (172.31.51.19) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2242.12; Thu, 2 Sep 2021 20:19:22 +0800 Received: from BJHW-MAIL-EX27.internal.baidu.com ([169.254.58.247]) by BJHW-MAIL-EX27.internal.baidu.com ([169.254.58.247]) with mapi id 15.01.2308.014; Thu, 2 Sep 2021 20:19:22 +0800 From: "Cai,Huoqing" To: "Cai,Huoqing" CC: Mauro Carvalho Chehab , "linux-media@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Hans Verkuil Subject: RE: [PATCH v3] usb: stkwebcam: Update the reference count of the usb device structure Thread-Topic: [PATCH v3] usb: stkwebcam: Update the reference count of the usb device structure Thread-Index: AQHXny9yBe2iT1uHw0mYSX48IokVQKuQqfuA Date: Thu, 2 Sep 2021 12:19:22 +0000 Message-ID: References: <20210901124650.31653-1-caihuoqing@baidu.com> In-Reply-To: <20210901124650.31653-1-caihuoqing@baidu.com> Accept-Language: zh-CN, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [172.18.80.52] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, +Cc Hans Verkuil Cai > Subject: [PATCH v3] usb: stkwebcam: Update the reference count of the usb > device structure > > Use usb_get_dev() to increment the reference count of the usb device > structure in order to avoid releasing the structure while it is still in > use. And use usb_put_dev() to decrement the reference count and thus, > when it will be equal to 0 the structure will be released. > > Signed-off-by: Cai Huoqing > --- > v2->v3: > *call usb_put_dev() in the error path of stk_camera_probe > *move v4l2_ctrl_handler_free/v4l2_device_unregister/kfree(dev) > from stk_camera_disconnect() to stk_v4l_dev_release() > > drivers/media/usb/stkwebcam/stk-webcam.c | 11 +++++++---- > 1 file changed, 7 insertions(+), 4 deletions(-) > > diff --git a/drivers/media/usb/stkwebcam/stk-webcam.c > b/drivers/media/usb/stkwebcam/stk-webcam.c > index 0e231e576dc3..9f445e6ab5fa 100644 > --- a/drivers/media/usb/stkwebcam/stk-webcam.c > +++ b/drivers/media/usb/stkwebcam/stk-webcam.c > @@ -1234,6 +1234,11 @@ static void stk_v4l_dev_release(struct > video_device *vd) > if (dev->sio_bufs != NULL || dev->isobufs != NULL) > pr_err("We are leaking memory\n"); > usb_put_intf(dev->interface); > + usb_put_dev(dev->udev); > + > + v4l2_ctrl_handler_free(&dev->hdl); > + v4l2_device_unregister(&dev->v4l2_dev); > + kfree(dev); > } > > static const struct video_device stk_v4l_data = { > @@ -1309,7 +1314,7 @@ static int stk_camera_probe(struct usb_interface > *interface, > init_waitqueue_head(&dev->wait_frame); > dev->first_init = 1; /* webcam LED management */ > > - dev->udev = udev; > + dev->udev = usb_get_dev(udev); > dev->interface = interface; > usb_get_intf(interface); > > @@ -1365,6 +1370,7 @@ static int stk_camera_probe(struct usb_interface > *interface, > > error_put: > usb_put_intf(interface); > + usb_put_dev(dev->udev); > error: > v4l2_ctrl_handler_free(hdl); > v4l2_device_unregister(&dev->v4l2_dev); > @@ -1385,9 +1391,6 @@ static void stk_camera_disconnect(struct > usb_interface *interface) > video_device_node_name(&dev->vdev)); > > video_unregister_device(&dev->vdev); > - v4l2_ctrl_handler_free(&dev->hdl); > - v4l2_device_unregister(&dev->v4l2_dev); > - kfree(dev); > } > > #ifdef CONFIG_PM > -- > 2.25.1