Messages in this thread | | | Subject | Re: [RFC/RFT PATCH 3/6] uvcvideo: Protect queue internals with helper | From | Kieran Bingham <> | Date | Sat, 6 Jan 2018 18:37:24 +0000 |
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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 >
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