From be6d7e1f7d368f617c82290b834073a3e8a41f17 Mon Sep 17 00:00:00 2001 From: Kieran Bingham Date: Tue, 27 Mar 2018 17:46:02 +0100 Subject: [PATCH] FROMLIST: media: uvcvideo: queue: Support asynchronous buffer handling The buffer queue interface currently operates sequentially, processing buffers after they have fully completed. In preparation for supporting parallel tasks operating on the buffers, we will need to support buffers being processed on multiple CPUs. Adapt the uvc_queue_next_buffer() such that a reference count tracks the active use of the buffer, returning the buffer to the VB2 stack at completion. Change-Id: Ia42cca9bed7852175202017b042590d844e8c6b0 Signed-off-by: Kieran Bingham Signed-off-by: William Wu (am from https://patchwork.kernel.org/patch/10311051/) --- drivers/media/usb/uvc/uvc_queue.c | 61 +++++++++++++++++++++++++------ drivers/media/usb/uvc/uvcvideo.h | 4 ++ 2 files changed, 54 insertions(+), 11 deletions(-) diff --git a/drivers/media/usb/uvc/uvc_queue.c b/drivers/media/usb/uvc/uvc_queue.c index 6a60dc371520..e9d4a2c35e3a 100644 --- a/drivers/media/usb/uvc/uvc_queue.c +++ b/drivers/media/usb/uvc/uvc_queue.c @@ -134,6 +134,7 @@ static void uvc_buffer_queue(struct vb2_buffer *vb) spin_lock_irqsave(&queue->irqlock, flags); if (likely(!(queue->flags & UVC_QUEUE_DISCONNECTED))) { + kref_init(&buf->ref); list_add_tail(&buf->queue, &queue->irqqueue); } else { /* If the device is disconnected return the buffer to userspace @@ -446,28 +447,66 @@ struct uvc_buffer *uvc_queue_get_current_buffer(struct uvc_video_queue *queue) return nextbuf; } +/* + * uvc_queue_requeue: Requeue a buffer on our internal irqqueue + * + * Reuse a buffer through our internal queue without the need to 'prepare' + * The buffer will be returned to userspace through the uvc_buffer_queue call if + * the device has been disconnected + */ +static void uvc_queue_requeue(struct uvc_video_queue *queue, + struct uvc_buffer *buf) +{ + buf->error = 0; + buf->state = UVC_BUF_STATE_QUEUED; + buf->bytesused = 0; + vb2_set_plane_payload(&buf->buf.vb2_buf, 0, 0); + + uvc_buffer_queue(&buf->buf.vb2_buf); +} + +static void uvc_queue_buffer_complete(struct kref *ref) +{ + struct uvc_buffer *buf = container_of(ref, struct uvc_buffer, ref); + struct vb2_buffer *vb = &buf->buf.vb2_buf; + struct uvc_video_queue *queue = vb2_get_drv_priv(vb->vb2_queue); + + if ((queue->flags & UVC_QUEUE_DROP_CORRUPTED) && buf->error) { + uvc_queue_requeue(queue, buf); + return; + } + + buf->state = buf->error ? UVC_BUF_STATE_ERROR : UVC_BUF_STATE_DONE; + vb2_set_plane_payload(&buf->buf.vb2_buf, 0, buf->bytesused); + vb2_buffer_done(&buf->buf.vb2_buf, VB2_BUF_STATE_DONE); +} + +/* + * Release a reference on the buffer. Complete the buffer when the last + * reference is released + */ +void uvc_queue_buffer_release(struct uvc_buffer *buf) +{ + kref_put(&buf->ref, uvc_queue_buffer_complete); +} + +/* + * Remove this buffer from the queue. Lifetime will persist while async actions + * are still running (if any), and uvc_queue_buffer_release will give the buffer + * back to VB2 when all users have completed. + */ struct uvc_buffer *uvc_queue_next_buffer(struct uvc_video_queue *queue, struct uvc_buffer *buf) { struct uvc_buffer *nextbuf; unsigned long flags; - if ((queue->flags & UVC_QUEUE_DROP_CORRUPTED) && buf->error) { - buf->error = 0; - buf->state = UVC_BUF_STATE_QUEUED; - buf->bytesused = 0; - vb2_set_plane_payload(&buf->buf.vb2_buf, 0, 0); - return buf; - } - spin_lock_irqsave(&queue->irqlock, flags); list_del(&buf->queue); nextbuf = __uvc_queue_get_current_buffer(queue); spin_unlock_irqrestore(&queue->irqlock, flags); - buf->state = buf->error ? UVC_BUF_STATE_ERROR : UVC_BUF_STATE_DONE; - vb2_set_plane_payload(&buf->buf.vb2_buf, 0, buf->bytesused); - vb2_buffer_done(&buf->buf.vb2_buf, VB2_BUF_STATE_DONE); + uvc_queue_buffer_release(buf); return nextbuf; } diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h index 131373d08978..9e31ca87bc75 100644 --- a/drivers/media/usb/uvc/uvcvideo.h +++ b/drivers/media/usb/uvc/uvcvideo.h @@ -382,6 +382,9 @@ struct uvc_buffer { unsigned int bytesused; u32 pts; + + /* asynchronous buffer handling */ + struct kref ref; }; #define UVC_QUEUE_DISCONNECTED (1 << 0) @@ -685,6 +688,7 @@ extern void uvc_queue_cancel(struct uvc_video_queue *queue, int disconnect); extern struct uvc_buffer *uvc_queue_next_buffer(struct uvc_video_queue *queue, struct uvc_buffer *buf); struct uvc_buffer *uvc_queue_get_current_buffer(struct uvc_video_queue *queue); +void uvc_queue_buffer_release(struct uvc_buffer *buf); extern int uvc_queue_mmap(struct uvc_video_queue *queue, struct vm_area_struct *vma); extern unsigned int uvc_queue_poll(struct uvc_video_queue *queue,