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Message-ID: <954315b8-3e5c-4583-a904-d20fbd21aa3f@collabora.com>
Date:   Wed, 11 Oct 2023 11:32:12 +0200
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Subject: Re: [PATCH v10 11/54] media: videobuf2: Access vb2_queue bufs array
 through helper functions
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To:     Hans Verkuil <hverkuil-cisco@xs4all.nl>, 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: <20231003080704.43911-1-benjamin.gaignard@collabora.com>
 <20231003080704.43911-12-benjamin.gaignard@collabora.com>
 <bd0ba3d3-444a-4288-910f-4b8a84b90750@xs4all.nl>
From:   Benjamin Gaignard <benjamin.gaignard@collabora.com>
In-Reply-To: <bd0ba3d3-444a-4288-910f-4b8a84b90750@xs4all.nl>
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Le 11/10/2023 à 10:44, Hans Verkuil a écrit :
> On 03/10/2023 10:06, Benjamin Gaignard wrote:
>> This patch adds 2 helpers functions to add and remove vb2 buffers
>> from a queue. With these 2 and vb2_get_buffer(), bufs field of
>> struct vb2_queue becomes like a private member of the structure.
>>
>> After each call to vb2_get_buffer() we need to be sure that we get
>> a valid pointer so check the return value of all of them.
> This needs to be extended: checking the returned pointer is a preparation
> for when buffers can be deleted. As it is right now, checking for a
> NULL pointer isn't needed.
>
> I wonder if it isn't better to drop those checks and instead apply them
> at the tail end of this series when the actual work on deleting buffers
> starts (before patch 49, I think).

I think that checking vb2_get_buffer() return value while removing direct
call to queue buffers array doesn't hurt here.
It is also needed to do that before "media: videobuf2: Add helper to get queue number of buffers" patch.

Regards,
Benjamin

>
> Regards,
>
> 	Hans
>
>> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
>> ---
>>   .../media/common/videobuf2/videobuf2-core.c   | 151 +++++++++++++-----
>>   .../media/common/videobuf2/videobuf2-v4l2.c   |  51 ++++--
>>   2 files changed, 146 insertions(+), 56 deletions(-)
>