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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8ABF6C83F1A for ; Wed, 30 Aug 2023 18:53:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245362AbjH3SwL (ORCPT ); Wed, 30 Aug 2023 14:52:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52038 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244754AbjH3Nvx (ORCPT ); Wed, 30 Aug 2023 09:51:53 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ACA65E8; Wed, 30 Aug 2023 06:51:50 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 42AB661178; Wed, 30 Aug 2023 13:51:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7DD88C433C8; Wed, 30 Aug 2023 13:51:46 +0000 (UTC) Message-ID: <970e55be-d5ed-e4d5-b12a-451113b9be90@xs4all.nl> Date: Wed, 30 Aug 2023 15:51:45 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.12.0 Subject: Re: [PATCH v5 09/10] media: v4l2: Add DELETE_BUFS ioctl Content-Language: en-US, nl To: Benjamin Gaignard , mchehab@kernel.org, tfiga@chromium.org, m.szyprowski@samsung.com, ming.qian@nxp.com, ezequiel@vanguardiasur.com.ar, p.zabel@pengutronix.de, gregkh@linuxfoundation.org, nicolas.dufresne@collabora.com Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-arm-msm@vger.kernel.org, linux-rockchip@lists.infradead.org, linux-staging@lists.linux.dev, kernel@collabora.com References: <20230824092133.39510-1-benjamin.gaignard@collabora.com> <20230824092133.39510-10-benjamin.gaignard@collabora.com> From: Hans Verkuil In-Reply-To: <20230824092133.39510-10-benjamin.gaignard@collabora.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 24/08/2023 11:21, Benjamin Gaignard wrote: > VIDIOC_DELETE_BUFS ioctl allows to delete buffers from a queue. > The number of buffers to delete in given by count field of > struct v4l2_delete_buffers and the range start at the index > specified in the same structure. > > Signed-off-by: Benjamin Gaignard > --- > .../userspace-api/media/v4l/user-func.rst | 1 + > .../media/v4l/vidioc-delete-bufs.rst | 73 +++++++++++++++++++ > .../media/common/videobuf2/videobuf2-core.c | 34 +++++++++ > .../media/common/videobuf2/videobuf2-v4l2.c | 16 ++++ > drivers/media/v4l2-core/v4l2-dev.c | 1 + > drivers/media/v4l2-core/v4l2-ioctl.c | 17 +++++ > include/media/v4l2-ioctl.h | 4 + > include/media/videobuf2-core.h | 9 +++ > include/media/videobuf2-v4l2.h | 11 +++ > include/uapi/linux/videodev2.h | 17 +++++ > 10 files changed, 183 insertions(+) > create mode 100644 Documentation/userspace-api/media/v4l/vidioc-delete-bufs.rst > > diff --git a/Documentation/userspace-api/media/v4l/user-func.rst b/Documentation/userspace-api/media/v4l/user-func.rst > index 15ff0bf7bbe6..3fd567695477 100644 > --- a/Documentation/userspace-api/media/v4l/user-func.rst > +++ b/Documentation/userspace-api/media/v4l/user-func.rst > @@ -17,6 +17,7 @@ Function Reference > vidioc-dbg-g-chip-info > vidioc-dbg-g-register > vidioc-decoder-cmd > + vidioc-delete-bufs > vidioc-dqevent > vidioc-dv-timings-cap > vidioc-encoder-cmd > diff --git a/Documentation/userspace-api/media/v4l/vidioc-delete-bufs.rst b/Documentation/userspace-api/media/v4l/vidioc-delete-bufs.rst > new file mode 100644 > index 000000000000..a55fe6331fc8 > --- /dev/null > +++ b/Documentation/userspace-api/media/v4l/vidioc-delete-bufs.rst > @@ -0,0 +1,73 @@ > +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later > +.. c:namespace:: V4L > + > +.. _VIDIOC_DELETE_BUFS: > + > +************************ > +ioctl VIDIOC_DELETE_BUFS > +************************ > + > +Name > +==== > + > +VIDIOC_DELETE_BUFS - Deletes buffers from a queue > + > +Synopsis > +======== > + > +.. c:macro:: VIDIOC_DELETE_BUFs > + > +``int ioctl(int fd, VIDIOC_DELETE_BUFs, struct v4l2_delete_buffers *argp)`` > + > +Arguments > +========= > + > +``fd`` > + File descriptor returned by :c:func:`open()`. > + > +``argp`` > + Pointer to struct :c:type:`v4l2_delete_buffers`. > + > +Description > +=========== > + > +Applications can optionally call the :ref:`VIDIOC_DELETE_BUFS` ioctl to > +delete buffers from a queue. > + > +.. c:type:: v4l2_delete_buffers > + > +.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{8.5cm}| > + > +.. flat-table:: struct v4l2_delete_buffers > + :header-rows: 0 > + :stub-columns: 0 > + :widths: 1 1 2 > + > + * - __u32 > + - ``index`` > + - The starting buffer index to delete. > + * - __u32 > + - ``count`` > + - The number of buffers to be deleted. > + * - __u32 > + - ``type`` > + - Type of the stream or buffers, this is the same as the struct > + :c:type:`v4l2_format` ``type`` field. See > + :c:type:`v4l2_buf_type` for valid values. > + * - __u32 > + - ``reserved``\ [13] > + - A place holder for future extensions. Drivers and applications > + must set the array to zero. > + > +Return Value > +============ > + > +On success 0 is returned, on error -1 and the ``errno`` variable is set > +appropriately. The generic error codes are described at the > +:ref:`Generic Error Codes ` chapter. > + > +EBUSY > + File I/O is in progress. > + > +EINVAL > + The buffer ``index`` doesn't exist in the queue. > diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c > index 70e36389b704..3d915b4c33b2 100644 > --- a/drivers/media/common/videobuf2/videobuf2-core.c > +++ b/drivers/media/common/videobuf2/videobuf2-core.c > @@ -1634,6 +1634,40 @@ int vb2_core_prepare_buf(struct vb2_queue *q, unsigned int index, void *pb) > } > EXPORT_SYMBOL_GPL(vb2_core_prepare_buf); > > +int vb2_core_delete_buf(struct vb2_queue *q, unsigned int index) I didn't realize this the first time I reviewed this, but I would suggest that you change this to vb2_core_delete_bufs(struct vb2_queue *q, unsigned int index, unsigned int count) This is consistent with vb2_core_create_bufs, and I strongly suspect it will help with locking (mmap_lock), since you don't need to lock for every buffer you delete, you can do it up front. And you can move the index/count validation to the core as well, that will help if e.g. dvb would want to use this ioctl in the future. Regards, Hans