Hi Laurent,
On 30/07/2018 20:57, Laurent Pinchart wrote:
> Hi Kieran,
>
> Thank you for the patch.
>
> On Tuesday, 27 March 2018 19:46:01 EEST Kieran Bingham wrote:
>> Both uvc_start_streaming(), and uvc_stop_streaming() are called from
>> userspace context, with interrupts enabled. As such, they do not need to
>> save the IRQ state, and can use spin_lock_irq() and spin_unlock_irq()
>> respectively.
>>
>> Signed-off-by: Kieran Bingham <kieran.bingham@xxxxxxxxxxxxxxxx>
>>
>> ---
>>
>> v4:
>> - Rebase to v4.16 (linux-media/master)
>>
>> drivers/media/usb/uvc/uvc_queue.c | 10 ++++------
>> 1 file changed, 4 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/media/usb/uvc/uvc_queue.c
>> b/drivers/media/usb/uvc/uvc_queue.c index adcc4928fae4..698d9a5a5aae 100644
>> --- a/drivers/media/usb/uvc/uvc_queue.c
>> +++ b/drivers/media/usb/uvc/uvc_queue.c
>> @@ -169,7 +169,6 @@ static int uvc_start_streaming(struct vb2_queue *vq,
>> unsigned int count) {
>> struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
>> struct uvc_streaming *stream = uvc_queue_to_stream(queue);
>> - unsigned long flags;
>> int ret;
>>
>> queue->buf_used = 0;
>> @@ -178,9 +177,9 @@ static int uvc_start_streaming(struct vb2_queue *vq,
>> unsigned int count) if (ret == 0)
>> return 0;
>>
>> - spin_lock_irqsave(&queue->irqlock, flags);
>> + spin_lock_irq(&queue->irqlock);
>> uvc_queue_return_buffers(queue, UVC_BUF_STATE_QUEUED);
>> - spin_unlock_irqrestore(&queue->irqlock, flags);
>> + spin_unlock_irq(&queue->irqlock);
>>
>> return ret;
>> }
>> @@ -188,14 +187,13 @@ static int uvc_start_streaming(struct vb2_queue *vq,
>> unsigned int count) static void uvc_stop_streaming(struct vb2_queue *vq)
>> {
>> struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
>> - unsigned long flags;
>>
>> if (vq->type != V4L2_BUF_TYPE_META_CAPTURE)
>> uvc_video_enable(uvc_queue_to_stream(queue), 0);
>>
>> - spin_lock_irqsave(&queue->irqlock, flags);
>> + spin_lock_irq(&queue->irqlock);
>> uvc_queue_return_buffers(queue, UVC_BUF_STATE_ERROR);
>> - spin_unlock_irqrestore(&queue->irqlock, flags);
>> + spin_unlock_irq(&queue->irqlock);
>> }
>
> I think you missed my comment that stated
>
>> Please add a one-line comment above both functions to state
>>
>> /* Must be called with interrupts enabled. */
>
> Philipp Zabel commented that you could also add lockdep_assert_irqs_enabled(),
> and I think that's a good idea. I'll let you decide whether to do both, or
> only add lockdep_assert_irqs_enabled(), I'm fine with either option.
>
> With this fixed,
I think code should talk louder than comments (especially as it provides
runtime verification and assertions when lockdep is enabled) - so I've
gone for Philipp's suggestion here.
>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
>
Collected, thanks.
>> static const struct vb2_ops uvc_queue_qops = {
>
--
Regards
--
Kieran
