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Message-ID: <edaa388e-fc26-4318-b468-64366aa86699@xs4all.nl>
Date: Thu, 18 Jan 2024 12:50:44 +0100
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Subject: Re: [PATCH] media: media videobuf2: Stop direct calls to queue
 num_buffers field
Content-Language: en-US
To: Tomasz Figa <tfiga@chromium.org>,
 Benjamin Gaignard <benjamin.gaignard@collabora.com>
Cc: m.szyprowski@samsung.com, mchehab@kernel.org,
 linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
 kernel@collabora.com
References: <20240115170826.214519-1-benjamin.gaignard@collabora.com>
 <20240115170826.214519-2-benjamin.gaignard@collabora.com>
 <c832da45-c818-420d-aaf8-05c15c1e5426@xs4all.nl>
 <521a2a44-9ec1-4898-aca7-721d07e12643@collabora.com>
 <CAAFQd5DWOZwm2E8BwfONtjrcg289wPHJEe3TMZKsBvDcn3OfNw@mail.gmail.com>
From: Hans Verkuil <hverkuil-cisco@xs4all.nl>
In-Reply-To: <CAAFQd5DWOZwm2E8BwfONtjrcg289wPHJEe3TMZKsBvDcn3OfNw@mail.gmail.com>
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On 1/18/24 12:22, Tomasz Figa wrote:
> On Tue, Jan 16, 2024 at 6:32 PM Benjamin Gaignard
> <benjamin.gaignard@collabora.com> wrote:
>>
>>
>> Le 16/01/2024 à 10:21, Hans Verkuil a écrit :
>>> On 15/01/2024 18:08, Benjamin Gaignard wrote:
>>>> Use vb2_get_num_buffers() to avoid using queue num_buffers field directly.
>>>> This allows us to change how the number of buffers is computed in the
>>>> future.
>>>>
>>>> Fixes: c838530d230b ("media: media videobuf2: Be more flexible on the number of queue stored buffers")
>>>> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
>>>> ---
>>>>   drivers/media/common/videobuf2/videobuf2-core.c | 2 +-
>>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
>>>> index 41a832dd1426..b6bf8f232f48 100644
>>>> --- a/drivers/media/common/videobuf2/videobuf2-core.c
>>>> +++ b/drivers/media/common/videobuf2/videobuf2-core.c
>>>> @@ -989,7 +989,7 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
>>>>      bool no_previous_buffers = !q_num_bufs;
>>>>      int ret = 0;
>>>>
>>>> -    if (q->num_buffers == q->max_num_buffers) {
>>>> +    if (q_num_bufs == q->max_num_buffers) {
>>>>              dprintk(q, 1, "maximum number of buffers already allocated\n");
>>>>              return -ENOBUFS;
>>>>      }
>>> There is another case in vb2_ioctl_create_bufs() where num_buffers is accessed directly.
>>> Can you fix that one as well?
>>
>> It is removed by the patch I have send just after this one:
>> "media: core: Refactor vb2_ioctl_create_bufs() to always set capabilities flags"
> 
> I'd prefer that to be also included in this fix, so that it's all
> logically grouped together. Actually Hans also ended up including that
> change in his patch, without the commit message mentioning it.

Yeah, it's borderline. But I think it is better if this patch updates both
places, and then I'll make a v2 for my patch on top.

Regards,

	Hans

> 
> Best regards,
> Tomasz