On 06/16/17 09:39, Gustavo Padovan wrote:
> From: Gustavo Padovan <gustavo.pado...@collabora.com>
>
> Receive in-fence from userspace and add support for waiting on them
> before queueing the buffer to the driver. Buffers are only queued
> to the driver once they are ready. A buffer is ready when its
> in-fence signals.
>
> v2:
> - fix vb2_queue_or_prepare_buf() ret check
> - remove check for VB2_MEMORY_DMABUF only (Javier)
> - check num of ready buffers to start streaming
> - when queueing, start from the first ready buffer
> - handle queue cancel
>
> Signed-off-by: Gustavo Padovan <gustavo.pado...@collabora.com>
> ---
> drivers/media/Kconfig | 1 +
> drivers/media/v4l2-core/videobuf2-core.c | 97
> +++++++++++++++++++++++++-------
> drivers/media/v4l2-core/videobuf2-v4l2.c | 15 ++++-
> include/media/videobuf2-core.h | 7 ++-
> 4 files changed, 99 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/media/Kconfig b/drivers/media/Kconfig
> index 55d9c2b..3cd1d3d 100644
> --- a/drivers/media/Kconfig
> +++ b/drivers/media/Kconfig
> @@ -11,6 +11,7 @@ config CEC_NOTIFIER
> menuconfig MEDIA_SUPPORT
> tristate "Multimedia support"
> depends on HAS_IOMEM
> + select SYNC_FILE
Is this the right place for this? Shouldn't this be selected in
'config VIDEOBUF2_CORE'?
Fences are specific to vb2 after all.
> help
> If you want to use Webcams, Video grabber devices and/or TV devices
> enable this option and other options below.
> diff --git a/drivers/media/v4l2-core/videobuf2-core.c
> b/drivers/media/v4l2-core/videobuf2-core.c
> index ea83126..29aa9d4 100644
> --- a/drivers/media/v4l2-core/videobuf2-core.c
> +++ b/drivers/media/v4l2-core/videobuf2-core.c
> @@ -1279,6 +1279,22 @@ static int __buf_prepare(struct vb2_buffer *vb, const
> void *pb)
> return 0;
> }
>
> +static int __get_num_ready_buffers(struct vb2_queue *q)
> +{
> + struct vb2_buffer *vb;
> + int ready_count = 0;
> +
> + /* count num of buffers ready in front of the queued_list */
> + list_for_each_entry(vb, &q->queued_list, queued_entry) {
> + if (vb->in_fence && !dma_fence_is_signaled(vb->in_fence))
> + break;
Obviously the break is wrong as Mauro mentioned.
> +
> + ready_count++;
> + }
> +
> + return ready_count;
> +}
> +
> int vb2_core_prepare_buf(struct vb2_queue *q, unsigned int index, void *pb)
> {
> struct vb2_buffer *vb;
> @@ -1324,8 +1340,15 @@ static int vb2_start_streaming(struct vb2_queue *q)
> * If any buffers were queued before streamon,
> * we can now pass them to driver for processing.
> */
> - list_for_each_entry(vb, &q->queued_list, queued_entry)
> + list_for_each_entry(vb, &q->queued_list, queued_entry) {
> + if (vb->state != VB2_BUF_STATE_QUEUED)
> + continue;
I think this test is unnecessary.
> +
> + if (vb->in_fence && !dma_fence_is_signaled(vb->in_fence))
> + break;
> +
> __enqueue_in_driver(vb);
I would move the above test (after fixing it as Mauro said) to
__enqueue_in_driver.
I.e. if this is waiting for a fence then __enqueue_in_driver does nothing.
> + }
>
> /* Tell the driver to start streaming */
> q->start_streaming_called = 1;
> @@ -1369,33 +1392,55 @@ static int vb2_start_streaming(struct vb2_queue *q)
>
> static int __vb2_core_qbuf(struct vb2_buffer *vb, struct vb2_queue *q)
> {
> + struct vb2_buffer *b;
> int ret;
>
> /*
> * If already streaming, give the buffer to driver for processing.
> * If not, the buffer will be given to driver on next streamon.
> */
> - if (q->start_streaming_called)
> - __enqueue_in_driver(vb);
>
> - /*
> - * If streamon has been called, and we haven't yet called
> - * start_streaming() since not enough buffers were queued, and
> - * we now have reached the minimum number of queued buffers,
> - * then we can finally call start_streaming().
> - */
> - if (q->streaming && !q->start_streaming_called &&
> - q->queued_count >= q->min_buffers_needed) {
> - ret = vb2_start_streaming(q);
> - if (ret)
> - return ret;
> + if (q->start_streaming_called) {
> + list_for_each_entry(b, &q->queued_list, queued_entry) {
> + if (b->state != VB2_BUF_STATE_QUEUED)
> + continue;
> +
> + if (b->in_fence && !dma_fence_is_signaled(b->in_fence))
> + break;
Again, if this test is in __enqueue_in_driver, then you can keep the
original code. Why would you need to loop over all buffers anyway?
If a fence is ready then the callback will call this function for that
buffer. Everything works fine AFAICT without looping over buffers here.
> +
> + __enqueue_in_driver(b);
> + }
> + } else {
> + /*
> + * If streamon has been called, and we haven't yet called
> + * start_streaming() since not enough buffers were queued, and
> + * we now have reached the minimum number of queued buffers
> + * that are ready, then we can finally call start_streaming().
> + */
> + if (q->streaming &&
> + __get_num_ready_buffers(q) >= q->min_buffers_needed) {
Just combine this with the 'else' to an 'else if'. Saves an extra level of
indentation.
To follow-up from Mauro's comment: having an 'else if' here is fine.
> + ret = vb2_start_streaming(q);
> + if (ret)
> + return ret;
> + }
> }
>
> dprintk(1, "qbuf of buffer %d succeeded\n", vb->index);
> return 0;
> }
>
> -int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb)
> +static void vb2_qbuf_fence_cb(struct dma_fence *f, struct dma_fence_cb *cb)
> +{
> + struct vb2_buffer *vb = container_of(cb, struct vb2_buffer, fence_cb);
> +
> + dma_fence_put(vb->in_fence);
> + vb->in_fence = NULL;
> +
> + __vb2_core_qbuf(vb, vb->vb2_queue);
> +}
> +
> +int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb,
> + struct dma_fence *fence)
> {
> struct vb2_buffer *vb;
> int ret;
> @@ -1436,6 +1481,11 @@ int vb2_core_qbuf(struct vb2_queue *q, unsigned int
> index, void *pb)
> if (pb)
> call_void_bufop(q, fill_user_buffer, vb, pb);
>
> + vb->in_fence = fence;
> + if (fence && !dma_fence_add_callback(fence, &vb->fence_cb,
> + vb2_qbuf_fence_cb))
> + return 0;
Shouldn't this return an error? How would userspace know this failed?
> +
> return __vb2_core_qbuf(vb, q);
> }
> EXPORT_SYMBOL_GPL(vb2_core_qbuf);
> @@ -1647,6 +1697,7 @@ EXPORT_SYMBOL_GPL(vb2_core_dqbuf);
> static void __vb2_queue_cancel(struct vb2_queue *q)
> {
> unsigned int i;
> + struct vb2_buffer *vb;
>
> /*
> * Tell driver to stop all transactions and release all queued
> @@ -1669,6 +1720,14 @@ static void __vb2_queue_cancel(struct vb2_queue *q)
> WARN_ON(atomic_read(&q->owned_by_drv_count));
> }
>
> + list_for_each_entry(vb, &q->queued_list, queued_entry) {
> + if (vb->in_fence) {
> + dma_fence_remove_callback(vb->in_fence, &vb->fence_cb);
> + dma_fence_put(vb->in_fence);
> + vb->in_fence = NULL;
> + }
> + }
> +
> q->streaming = 0;
> q->start_streaming_called = 0;
> q->queued_count = 0;
> @@ -1735,7 +1794,7 @@ int vb2_core_streamon(struct vb2_queue *q, unsigned int
> type)
> * Tell driver to start streaming provided sufficient buffers
> * are available.
> */
> - if (q->queued_count >= q->min_buffers_needed) {
> + if (__get_num_ready_buffers(q) >= q->min_buffers_needed) {
> ret = v4l_vb2q_enable_media_source(q);
> if (ret)
> return ret;
> @@ -2250,7 +2309,7 @@ static int __vb2_init_fileio(struct vb2_queue *q, int
> read)
> * Queue all buffers.
> */
> for (i = 0; i < q->num_buffers; i++) {
> - ret = vb2_core_qbuf(q, i, NULL);
> + ret = vb2_core_qbuf(q, i, NULL, NULL);
> if (ret)
> goto err_reqbufs;
> fileio->bufs[i].queued = 1;
> @@ -2429,7 +2488,7 @@ static size_t __vb2_perform_fileio(struct vb2_queue *q,
> char __user *data, size_
>
> if (copy_timestamp)
> b->timestamp = ktime_get_ns();
> - ret = vb2_core_qbuf(q, index, NULL);
> + ret = vb2_core_qbuf(q, index, NULL, NULL);
> dprintk(5, "vb2_dbuf result: %d\n", ret);
> if (ret)
> return ret;
> @@ -2532,7 +2591,7 @@ static int vb2_thread(void *data)
> if (copy_timestamp)
> vb->timestamp = ktime_get_ns();;
> if (!threadio->stop)
> - ret = vb2_core_qbuf(q, vb->index, NULL);
> + ret = vb2_core_qbuf(q, vb->index, NULL, NULL);
> call_void_qop(q, wait_prepare, q);
> if (ret || threadio->stop)
> break;
> diff --git a/drivers/media/v4l2-core/videobuf2-v4l2.c
> b/drivers/media/v4l2-core/videobuf2-v4l2.c
> index 110fb45..e6ad77f 100644
> --- a/drivers/media/v4l2-core/videobuf2-v4l2.c
> +++ b/drivers/media/v4l2-core/videobuf2-v4l2.c
> @@ -23,6 +23,7 @@
> #include <linux/sched.h>
> #include <linux/freezer.h>
> #include <linux/kthread.h>
> +#include <linux/sync_file.h>
>
> #include <media/v4l2-dev.h>
> #include <media/v4l2-fh.h>
> @@ -560,6 +561,7 @@ EXPORT_SYMBOL_GPL(vb2_create_bufs);
>
> int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b)
> {
> + struct dma_fence *fence = NULL;
> int ret;
>
> if (vb2_fileio_is_active(q)) {
> @@ -568,7 +570,18 @@ int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b)
> }
>
> ret = vb2_queue_or_prepare_buf(q, b, "qbuf");
> - return ret ? ret : vb2_core_qbuf(q, b->index, b);
> + if (ret)
> + return ret;
> +
> + if (b->flags & V4L2_BUF_FLAG_IN_FENCE) {
> + fence = sync_file_get_fence(b->fence_fd);
> + if (!fence) {
> + dprintk(1, "failed to get in-fence from fd\n");
> + return -EINVAL;
> + }
> + }
> +
> + return ret ? ret : vb2_core_qbuf(q, b->index, b, fence);
> }
> EXPORT_SYMBOL_GPL(vb2_qbuf);
>
> diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
> index cb97c22..aa43e43 100644
> --- a/include/media/videobuf2-core.h
> +++ b/include/media/videobuf2-core.h
> @@ -16,6 +16,7 @@
> #include <linux/mutex.h>
> #include <linux/poll.h>
> #include <linux/dma-buf.h>
> +#include <linux/dma-fence.h>
>
> #define VB2_MAX_FRAME (32)
> #define VB2_MAX_PLANES (8)
> @@ -259,6 +260,9 @@ struct vb2_buffer {
>
> struct list_head queued_entry;
> struct list_head done_entry;
> +
> + struct dma_fence *in_fence;
> + struct dma_fence_cb fence_cb;
> #ifdef CONFIG_VIDEO_ADV_DEBUG
> /*
> * Counters for how often these buffer-related ops are
> @@ -727,7 +731,8 @@ int vb2_core_prepare_buf(struct vb2_queue *q, unsigned
> int index, void *pb);
> * The return values from this function are intended to be directly returned
> * from vidioc_qbuf handler in driver.
> */
> -int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb);
> +int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb,
> + struct dma_fence *fence);
>
> /**
> * vb2_core_dqbuf() - Dequeue a buffer to the userspace
>
Regards,
Hans
