[RFC 03/10] [media] vb2: add in-fence support to QBUF

Gustavo Padovan
2017-03-13T19:20:52Z

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

Receive in-fence from userspace and support for waiting on them
before queueing the buffer for the driver.

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
---
drivers/media/Kconfig | 1 +
drivers/media/v4l2-core/videobuf2-core.c | 24 ++++++++++++++++++++----
drivers/media/v4l2-core/videobuf2-v4l2.c | 14 +++++++++++++-
include/media/videobuf2-core.h | 7 ++++++-
4 files changed, 40 insertions(+), 6 deletions(-)

diff --git a/drivers/media/Kconfig b/drivers/media/Kconfig
index 3512316..7c5a0e0 100644
--- a/drivers/media/Kconfig
+++ b/drivers/media/Kconfig
@@ -5,6 +5,7 @@
menuconfig MEDIA_SUPPORT
tristate "Multimedia support"
depends on HAS_IOMEM
+ select SYNC_FILE
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 0e30fcd..e0e7109 100644
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -1400,7 +1400,18 @@ static int __vb2_core_qbuf(struct vb2_buffer *vb, struct vb2_queue *q)
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;
@@ -1432,6 +1443,11 @@ 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;
+
return __vb2_core_qbuf(vb, q);
}
EXPORT_SYMBOL_GPL(vb2_core_qbuf);
@@ -2246,7 +2262,7 @@ 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;
@@ -2425,7 +2441,7 @@ 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;
@@ -2528,7 +2544,7 @@ 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 d23c1bf..c164aa0 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>
@@ -557,6 +558,7 @@ 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)) {
@@ -565,7 +567,17 @@ 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 (b->flags & V4L2_BUF_FLAG_IN_FENCE) {
+ if (b->memory != VB2_MEMORY_DMABUF)
+ return -EINVAL;
+
+ fence = sync_file_get_fence(b->fence_fd);
+ if (!fence)
+ 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 ac5898a..fe2de99 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
--
2.9.3