lkml.org 
[lkml]   [2018]   [Jan]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [RFC/RFT PATCH 3/6] uvcvideo: Protect queue internals with helper
From
Date
Hi Guennadi,

On 04/01/18 18:25, Guennadi Liakhovetski wrote:
> Hi Kieran,
>
> On Wed, 3 Jan 2018, Kieran Bingham wrote:
>
>> From: Kieran Bingham <kieran.bingham@ideasonboard.com>
>>
>> The URB completion operation obtains the current buffer by reading
>> directly into the queue internal interface.
>>
>> Protect this queue abstraction by providing a helper
>> uvc_queue_get_current_buffer() which can be used by both the decode
>> task, and the uvc_queue_next_buffer() functions.
>>
>> Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
>> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
>> ---
>> drivers/media/usb/uvc/uvc_queue.c | 34 +++++++++++++++++++++++++++-----
>> drivers/media/usb/uvc/uvc_video.c | 7 +------
>> drivers/media/usb/uvc/uvcvideo.h | 2 ++-
>> 3 files changed, 32 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/media/usb/uvc/uvc_queue.c b/drivers/media/usb/uvc/uvc_queue.c
>> index c8d78b2f3de4..0711e3d9ff76 100644
>> --- a/drivers/media/usb/uvc/uvc_queue.c
>> +++ b/drivers/media/usb/uvc/uvc_queue.c
>> @@ -399,6 +399,34 @@ void uvc_queue_cancel(struct uvc_video_queue *queue, int disconnect)
>> spin_unlock_irqrestore(&queue->irqlock, flags);
>> }
>>
>> +/*
>> + * uvc_queue_get_current_buffer: Obtain the current working output buffer
>> + *
>> + * Buffers may span multiple packets, and even URBs, therefore the active buffer
>> + * remains on the queue until the EOF marker.
>> + */
>> +static struct uvc_buffer *
>> +__uvc_queue_get_current_buffer(struct uvc_video_queue *queue)
>> +{
>> + if (!list_empty(&queue->irqqueue))
>> + return list_first_entry(&queue->irqqueue, struct uvc_buffer,
>> + queue);
>> + else
>> + return NULL;
>
> I think the preferred style is not to use "else" in such cases. It might
> even be prettier to write
>
> if (list_empty(...))
> return NULL;
>
> return list_first_entry(...);

Ah yes, I believe you are correct.
Good spot!

Fixed, and looks much neater.

--
Kieran

>
> Thanks
> Guennadi
>

\
 
 \ /
  Last update: 2018-01-06 19:38    [W:0.045 / U:1.128 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site