[RFC 10/10] [media] vb2: add out-fence support to QBUF

Gustavo Padovan
2017-03-13T19:21:11Z

From: Gustavo Padovan <gustavo.padovan@collabora.com>

If V4L2_BUF_FLAG_OUT_FENCE flag is present on the QBUF call we create
an out_fence for the buffer and return it to userspace on the fence_fd
field.

The fence is signaled on buffer_done(), when the job on the buffer is
finished.

TODO: clean up on __vb2_queue_cancel()

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
---
drivers/media/v4l2-core/videobuf2-core.c | 6 ++++++
drivers/media/v4l2-core/videobuf2-v4l2.c | 15 ++++++++++++++-
2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
index 54b1404..ca8abcc 100644
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -356,6 +356,7 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory,
vb->planes[plane].length = plane_sizes[plane];
vb->planes[plane].min_length = plane_sizes[plane];
}
+ vb->out_fence_fd = -1;
q->bufs[vb->index] = vb;

/* Allocate video buffer memory for the MMAP type */
@@ -940,6 +941,11 @@ void vb2_buffer_done(struct vb2_buffer *vb, enum vb2_buffer_state state)
__enqueue_in_driver(vb);
return;
default:
+ dma_fence_signal(vb->out_fence);
+ dma_fence_put(vb->out_fence);
+ vb->out_fence = NULL;
+ vb->out_fence_fd = -1;
+
/* Inform any processes that may be waiting for buffers */
wake_up(&q->done_wq);
break;
diff --git a/drivers/media/v4l2-core/videobuf2-v4l2.c b/drivers/media/v4l2-core/videobuf2-v4l2.c
index c164aa0..1b43d9f 100644
--- a/drivers/media/v4l2-core/videobuf2-v4l2.c
+++ b/drivers/media/v4l2-core/videobuf2-v4l2.c
@@ -204,9 +204,14 @@ static void __fill_v4l2_buffer(struct vb2_buffer *vb, void *pb)
b->timestamp = ns_to_timeval(vb->timestamp);
b->timecode = vbuf->timecode;
b->sequence = vbuf->sequence;
- b->fence_fd = -1;
+ b->fence_fd = vb->out_fence_fd;
b->reserved = 0;

+ if (vb->sync_file) {
+ fd_install(vb->out_fence_fd, vb->sync_file->file);
+ vb->sync_file = NULL;
+ }
+
if (q->is_multiplanar) {
/*
* Fill in plane-related data if userspace provided an array
@@ -577,6 +582,14 @@ int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b)
return -EINVAL;
}

+ if (b->flags & V4L2_BUF_FLAG_OUT_FENCE) {
+ ret = vb2_setup_out_fence(q, b->index);
+ if (ret) {
+ dma_fence_put(fence);
+ return ret;
+ }
+ }
+
return ret ? ret : vb2_core_qbuf(q, b->index, b, fence);
}
EXPORT_SYMBOL_GPL(vb2_qbuf);
--
2.9.3