Make vb2 aware of requests. Drivers can specify whether a given queue
can accept requests or not. Queues that accept requests will block on a
buffer that is part of a request until that request is submitted.
Signed-off-by: Alexandre Courbot <acour...@chromium.org>
---
drivers/media/v4l2-core/videobuf2-core.c | 133 +++++++++++++++++++++++++++++--
drivers/media/v4l2-core/videobuf2-v4l2.c | 28 ++++++-
include/media/videobuf2-core.h | 15 +++-
3 files changed, 168 insertions(+), 8 deletions(-)
diff --git a/drivers/media/v4l2-core/videobuf2-core.c
b/drivers/media/v4l2-core/videobuf2-core.c
index cb115ba6a1d2..4a69ac12ee88 100644
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -26,6 +26,7 @@
#include <media/videobuf2-core.h>
#include <media/v4l2-mc.h>
+#include <media/media-request.h>
#include <trace/events/vb2.h>
@@ -922,6 +923,17 @@ void vb2_buffer_done(struct vb2_buffer *vb, enum
vb2_buffer_state state)
vb->state = state;
}
atomic_dec(&q->owned_by_drv_count);
+ if (vb->request) {
+ struct media_request *req = vb->request;
+
+ if (atomic_dec_and_test(&req->buf_cpt))
+ media_request_complete(vb->request);
+
+ /* release reference acquired during qbuf */
+ vb->request = NULL;
+ media_request_put(req);
+ }
+
spin_unlock_irqrestore(&q->done_lock, flags);
trace_vb2_buf_done(q, vb);
@@ -1298,6 +1310,53 @@ int vb2_core_prepare_buf(struct vb2_queue *q, unsigned
int index, void *pb)
}
EXPORT_SYMBOL_GPL(vb2_core_prepare_buf);
+/**
+ * vb2_check_buf_req_status() - Validate request state of a buffer
+ * @vb: buffer to check
+ *
+ * Returns true if a buffer is ready to be passed to the driver request-wise.
+ * This means that neither this buffer nor any previously-queued buffer is
+ * associated to a request that is not yet submitted.
+ *
+ * If this function returns false, then the buffer shall not be passed to its
+ * driver since the request state is not completely built yet. In that case,
+ * this function will register a notifier to be called when the request is
+ * submitted and the queue can be unblocked.
+ *
+ * This function must be called with req_lock held.
+ */
+static bool vb2_check_buf_req_status(struct vb2_buffer *vb)
+{
+ struct media_request *req = vb->request;
+ struct vb2_queue *q = vb->vb2_queue;
+ int ret = false;
+
+ mutex_lock(&q->req_lock);
+
+ if (!req) {
+ ret = !q->waiting_req;
+ goto done;
+ }
+
+ mutex_lock(&req->lock);
+ if (req->state == MEDIA_REQUEST_STATE_SUBMITTED) {
+ mutex_unlock(&req->lock);
+ ret = !q->waiting_req;
+ goto done;
+ }
+
+ if (!q->waiting_req) {
+ q->waiting_req = true;
+ atomic_notifier_chain_register(&req->submit_notif,
+ &q->req_blk);
+ }
+ mutex_unlock(&req->lock);
+
+done:
+ mutex_unlock(&q->req_lock);
+ return ret;
+}
+
/**
* vb2_start_streaming() - Attempt to start streaming.
* @q: videobuf2 queue
@@ -1318,8 +1377,11 @@ 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 (!vb2_check_buf_req_status(vb))
+ break;
__enqueue_in_driver(vb);
+ }
/* Tell the driver to start streaming */
q->start_streaming_called = 1;
@@ -1361,7 +1423,46 @@ static int vb2_start_streaming(struct vb2_queue *q)
return ret;
}
-int vb2_core_qbuf(struct vb2_queue *q, unsigned int index, void *pb)
+/**
+ * vb2_unblock_requests() - unblock a queue waiting for a request submission
+ * @nb: notifier block that has been registered
+ * @action: unused
+ * @data: request that has been submitted
+ *
+ * This is a callback function that is registered when
+ * vb2_check_buf_req_status() returns false. It is invoked when the request
+ * blocking the queue has been submitted. This means its buffers (and all
+ * following valid buffers) can be passed to drivers.
+ */
+static int vb2_unblock_requests(struct notifier_block *nb, unsigned long
action,
+ void *data)
+{
+ struct vb2_queue *q = container_of(nb, struct vb2_queue, req_blk);
+ struct media_request *req = data;
+ struct vb2_buffer *vb;
+ bool found_request = false;
+
+ mutex_lock(&q->req_lock);
+ atomic_notifier_chain_unregister(&req->submit_notif, &q->req_blk);
+ q->waiting_req = false;
+ mutex_unlock(&q->req_lock);
+
+ list_for_each_entry(vb, &q->queued_list, queued_entry) {
+ /* All buffers before our request are already passed to the
driver */
+ if (!found_request && vb->request != req)
+ continue;
+ found_request = true;
+
+ if (!vb2_check_buf_req_status(vb))
+ break;
+ __enqueue_in_driver(vb);
+ }
+
+ return 0;
+}
+
+int vb2_core_qbuf(struct vb2_queue *q, unsigned int index,
+ struct media_request *req, void *pb)
{
struct vb2_buffer *vb;
int ret;
@@ -1384,6 +1485,24 @@ int vb2_core_qbuf(struct vb2_queue *q, unsigned int
index, void *pb)
return -EINVAL;
}
+ vb->request = req;
+ if (req) {
+ struct vb2_buffer *_vb;
+
+ /* does the queue support requests? */
+ if (!q->allow_requests)
+ return -EINVAL;
+
+ /* do we already have a buffer for this request in the queue? */
+ list_for_each_entry(_vb, &q->queued_list, queued_entry)
+ if (_vb->request == req)
+ return -EBUSY;
+
+ /* make sure the request stays alive as long as we need */
+ media_request_get(req);
+ atomic_inc(&req->buf_cpt);
+ }
+
/*
* Add to the queued buffers list, a buffer will stay on it until
* dequeued in dqbuf.
@@ -1402,7 +1521,7 @@ int vb2_core_qbuf(struct vb2_queue *q, unsigned int
index, void *pb)
* 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)
+ if (q->start_streaming_called && vb2_check_buf_req_status(vb))
__enqueue_in_driver(vb);
/* Fill buffer information for the userspace */
@@ -1993,6 +2112,8 @@ int vb2_core_queue_init(struct vb2_queue *q)
spin_lock_init(&q->done_lock);
mutex_init(&q->mmap_lock);
init_waitqueue_head(&q->done_wq);
+ mutex_init(&q->req_lock);
+ q->req_blk.notifier_call = vb2_unblock_requests;
if (q->buf_struct_size == 0)
q->buf_struct_size = sizeof(struct vb2_buffer);
@@ -2242,7 +2363,7 @@ 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;
@@ -2421,7 +2542,7 @@ 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;
@@ -2524,7 +2645,7 @@ 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 0f8edbdebe30..267fe2d669b2 100644
--- a/drivers/media/v4l2-core/videobuf2-v4l2.c
+++ b/drivers/media/v4l2-core/videobuf2-v4l2.c
@@ -30,6 +30,7 @@
#include <media/v4l2-common.h>
#include <media/videobuf2-v4l2.h>
+#include <media/media-request.h>
static int debug;
module_param(debug, int, 0644);
@@ -561,6 +562,7 @@ EXPORT_SYMBOL_GPL(vb2_create_bufs);
int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b)
{
+ struct media_request *req = NULL;
int ret;
if (vb2_fileio_is_active(q)) {
@@ -568,8 +570,32 @@ int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b)
return -EBUSY;
}
+ /*
+ * The caller should have validated that the request is valid,
+ * so we just need to look it up without further checking
+ */
+ if (b->request_fd > 0) {
+ req = media_request_get_from_fd(b->request_fd);
+ if (!req)
+ return -EINVAL;
+
+ mutex_lock(&req->lock);
+ if (req->state != MEDIA_REQUEST_STATE_IDLE) {
+ mutex_unlock(&req->lock);
+ media_request_put(req);
+ return -EINVAL;
+ }
+ mutex_unlock(&req->lock);
+ }
+
ret = vb2_queue_or_prepare_buf(q, b, "qbuf");
- return ret ? ret : vb2_core_qbuf(q, b->index, b);
+ if (!ret)
+ ret = vb2_core_qbuf(q, b->index, req, b);
+
+ if (req)
+ media_request_put(req);
+
+ return ret;
}
EXPORT_SYMBOL_GPL(vb2_qbuf);
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index ef9b64398c8c..7bb17c842ab4 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -237,6 +237,7 @@ struct vb2_queue;
* on an internal driver queue
* @planes: private per-plane information; do not change
* @timestamp: frame timestamp in ns
+ * @request: request the buffer belongs to, if any
*/
struct vb2_buffer {
struct vb2_queue *vb2_queue;
@@ -246,6 +247,7 @@ struct vb2_buffer {
unsigned int num_planes;
struct vb2_plane planes[VB2_MAX_PLANES];
u64 timestamp;
+ struct media_request *request;
/* private: internal use only
*
@@ -443,6 +445,7 @@ struct vb2_buf_ops {
* @quirk_poll_must_check_waiting_for_buffers: Return POLLERR at poll when QBUF
* has not been called. This is a vb1 idiom that has been adopted
* also by vb2.
+ * @allow_requests: whether requests are supported on this queue.
* @lock: pointer to a mutex that protects the vb2_queue struct. The
* driver can set this to a mutex to let the v4l2 core serialize
* the queuing ioctls. If the driver wants to handle locking
@@ -500,6 +503,9 @@ struct vb2_buf_ops {
* when a buffer with the V4L2_BUF_FLAG_LAST is dequeued.
* @fileio: file io emulator internal data, used only if emulator is active
* @threadio: thread io internal data, used only if thread is active
+ * @req_lock: protects req_blk and waiting_req
+ * @req_blk: notifier to be called when waiting for a request to be submitted
+ * @waiting_req:whether this queue is currently waiting on a request submission
*/
struct vb2_queue {
unsigned int type;
@@ -511,6 +517,7 @@ struct vb2_queue {
unsigned fileio_write_immediately:1;
unsigned allow_zero_bytesused:1;
unsigned quirk_poll_must_check_waiting_for_buffers:1;
+ unsigned allow_requests:1;
struct mutex *lock;
void *owner;
@@ -554,6 +561,10 @@ struct vb2_queue {
struct vb2_fileio_data *fileio;
struct vb2_threadio_data *threadio;
+ struct mutex req_lock;
+ struct notifier_block req_blk;
+ bool waiting_req;
+
#ifdef CONFIG_VIDEO_ADV_DEBUG
/*
* Counters for how often these queue-related ops are
@@ -724,6 +735,7 @@ int vb2_core_prepare_buf(struct vb2_queue *q, unsigned int
index, void *pb);
*
* @q: videobuf2 queue
* @index: id number of the buffer
+ * @req: request this buffer belongs to, if any
* @pb: buffer structure passed from userspace to vidioc_qbuf
handler
* in driver
*
@@ -740,7 +752,8 @@ 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,
+ struct media_request *req, void *pb);
/**
* vb2_core_dqbuf() - Dequeue a buffer to the userspace
--
2.16.0.rc1.238.g530d649a79-goog
