Hi Kieran,
Thank you for the patch.
On Friday, 12 January 2018 11:19:26 EET Kieran Bingham wrote:
> Both uvc_start_streaming(), and uvc_stop_streaming() are called from
> userspace context. As such, they do not need to save the IRQ state, and
> can use spin_lock_irq() and spin_unlock_irq() respectively.
Note that userspace context isn't enough, the key part is that they're called
with interrupts enabled. If they were called from userspace context but under
a spin_lock_irq() you couldn't use spin_unlock_irq() in those functions.
> Signed-off-by: Kieran Bingham <kieran.bingham@xxxxxxxxxxxxxxxx>
> ---
> 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 4a581d631525..ddac4d89a291 100644
> --- a/drivers/media/usb/uvc/uvc_queue.c
> +++ b/drivers/media/usb/uvc/uvc_queue.c
> @@ -158,7 +158,6 @@ 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;
> @@ -167,9 +166,9 @@ 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;
> }
> @@ -178,13 +177,12 @@ static void uvc_stop_streaming(struct vb2_queue *vq)
> {
> struct uvc_video_queue *queue = vb2_get_drv_priv(vq);
> struct uvc_streaming *stream = uvc_queue_to_stream(queue);
> - unsigned long flags;
>
> uvc_video_enable(stream, 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);
> }
Please add a one-line comment above both functions to state
/* Must be called with interrupts enabled. */
With this and the commit message updated,
Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> static const struct vb2_ops uvc_queue_qops = {
--
Regards,
Laurent Pinchart
