[PATCH v9 12/53] media: videobuf2: Be more flexible on the number of queue stored buffers

[Benjamin Gaignard]

Add 'max_num_buffers' field in vb2_queue struct to let drivers decide
how many buffers could be stored in a queue.
This require 'bufs' array to be allocated at queue init time and freed
when releasing the queue.
By default VB2_MAX_FRAME remains the limit.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxxxxx>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
---
changes in version 9:
- Correctly initialize max_num_buffers in vb2_core_queue_init()

 .../media/common/videobuf2/videobuf2-core.c   | 41 +++++++++++++++----
 .../media/common/videobuf2/videobuf2-v4l2.c   |  4 +-
 include/media/videobuf2-core.h                |  4 +-
 3 files changed, 37 insertions(+), 12 deletions(-)

diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
index 9c9eef6ee423..098966846e12 100644
--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c
@@ -412,7 +412,7 @@ static void init_buffer_cache_hints(struct vb2_queue *q, struct vb2_buffer *vb)
  */
 static void vb2_queue_add_buffer(struct vb2_queue *q, struct vb2_buffer *vb, unsigned int index)
 {
-	WARN_ON(index >= VB2_MAX_FRAME || q->bufs[index]);
+	WARN_ON(index >= q->max_num_buffers || q->bufs[index]);
 
 	q->bufs[index] = vb;
 	vb->index = index;
@@ -444,9 +444,9 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory,
 	struct vb2_buffer *vb;
 	int ret;
 
-	/* Ensure that q->num_buffers+num_buffers is below VB2_MAX_FRAME */
+	/* Ensure that the number of already queue + num_buffers is below q->max_num_buffers */
 	num_buffers = min_t(unsigned int, num_buffers,
-			    VB2_MAX_FRAME - q->num_buffers);
+			    q->max_num_buffers - q->num_buffers);
 
 	for (buffer = 0; buffer < num_buffers; ++buffer) {
 		/* Allocate vb2 buffer structures */
@@ -805,7 +805,7 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
 	unsigned plane_sizes[VB2_MAX_PLANES] = { };
 	bool non_coherent_mem = flags & V4L2_MEMORY_FLAG_NON_COHERENT;
 	unsigned int i;
-	int ret;
+	int ret = 0;
 
 	if (q->streaming) {
 		dprintk(q, 1, "streaming active\n");
@@ -849,17 +849,22 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
 	/*
 	 * Make sure the requested values and current defaults are sane.
 	 */
-	WARN_ON(q->min_buffers_needed > VB2_MAX_FRAME);
 	num_buffers = max_t(unsigned int, *count, q->min_buffers_needed);
-	num_buffers = min_t(unsigned int, num_buffers, VB2_MAX_FRAME);
+	num_buffers = min_t(unsigned int, num_buffers, q->max_num_buffers);
 	memset(q->alloc_devs, 0, sizeof(q->alloc_devs));
 	/*
 	 * Set this now to ensure that drivers see the correct q->memory value
 	 * in the queue_setup op.
 	 */
 	mutex_lock(&q->mmap_lock);
+	if (!q->bufs)
+		q->bufs = kcalloc(q->max_num_buffers, sizeof(*q->bufs), GFP_KERNEL);
+	if (!q->bufs)
+		ret = -ENOMEM;
 	q->memory = memory;
 	mutex_unlock(&q->mmap_lock);
+	if (ret)
+		return ret;
 	set_queue_coherency(q, non_coherent_mem);
 
 	/*
@@ -965,9 +970,9 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
 	unsigned plane_sizes[VB2_MAX_PLANES] = { };
 	bool non_coherent_mem = flags & V4L2_MEMORY_FLAG_NON_COHERENT;
 	bool no_previous_buffers = !q->num_buffers;
-	int ret;
+	int ret = 0;
 
-	if (q->num_buffers == VB2_MAX_FRAME) {
+	if (q->num_buffers == q->max_num_buffers) {
 		dprintk(q, 1, "maximum number of buffers already allocated\n");
 		return -ENOBUFS;
 	}
@@ -984,7 +989,13 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
 		 */
 		mutex_lock(&q->mmap_lock);
 		q->memory = memory;
+		if (!q->bufs)
+			q->bufs = kcalloc(q->max_num_buffers, sizeof(*q->bufs), GFP_KERNEL);
+		if (!q->bufs)
+			ret = -ENOMEM;
 		mutex_unlock(&q->mmap_lock);
+		if (ret)
+			return ret;
 		q->waiting_for_buffers = !q->is_output;
 		set_queue_coherency(q, non_coherent_mem);
 	} else {
@@ -996,7 +1007,7 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
 			return -EINVAL;
 	}
 
-	num_buffers = min(*count, VB2_MAX_FRAME - q->num_buffers);
+	num_buffers = min(*count, q->max_num_buffers - q->num_buffers);
 
 	if (requested_planes && requested_sizes) {
 		num_planes = requested_planes;
@@ -2455,6 +2466,12 @@ int vb2_core_queue_init(struct vb2_queue *q)
 	/*
 	 * Sanity check
 	 */
+	if (!q->max_num_buffers)
+		q->max_num_buffers = VB2_MAX_FRAME;
+
+	/* The maximum is limited by offset cookie encoding pattern */
+	q->max_num_buffers = min_t(unsigned int, q->max_num_buffers, BUFFER_INDEX_MASK + 1);
+
 	if (WARN_ON(!q)			  ||
 	    WARN_ON(!q->ops)		  ||
 	    WARN_ON(!q->mem_ops)	  ||
@@ -2464,6 +2481,10 @@ int vb2_core_queue_init(struct vb2_queue *q)
 	    WARN_ON(!q->ops->buf_queue))
 		return -EINVAL;
 
+	if (WARN_ON(q->max_num_buffers > BUFFER_INDEX_MASK + 1) ||
+	    WARN_ON(q->min_buffers_needed > q->max_num_buffers))
+		return -EINVAL;
+
 	if (WARN_ON(q->requires_requests && !q->supports_requests))
 		return -EINVAL;
 
@@ -2510,6 +2531,8 @@ void vb2_core_queue_release(struct vb2_queue *q)
 	__vb2_queue_cancel(q);
 	mutex_lock(&q->mmap_lock);
 	__vb2_queue_free(q, q->num_buffers);
+	kfree(q->bufs);
+	q->bufs = NULL;
 	mutex_unlock(&q->mmap_lock);
 }
 EXPORT_SYMBOL_GPL(vb2_core_queue_release);
diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
index 3395e702ad1f..278ea1107b01 100644
--- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
+++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
@@ -1156,7 +1156,7 @@ int _vb2_fop_release(struct file *file, struct mutex *lock)
 
 	if (lock)
 		mutex_lock(lock);
-	if (file->private_data == vdev->queue->owner) {
+	if (!vdev->queue->owner || file->private_data == vdev->queue->owner) {
 		vb2_queue_release(vdev->queue);
 		vdev->queue->owner = NULL;
 	}
@@ -1284,7 +1284,7 @@ void vb2_video_unregister_device(struct video_device *vdev)
 	 */
 	get_device(&vdev->dev);
 	video_unregister_device(vdev);
-	if (vdev->queue && vdev->queue->owner) {
+	if (vdev->queue) {
 		struct mutex *lock = vdev->queue->lock ?
 			vdev->queue->lock : vdev->lock;
 
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index cd3ff1cd759d..1d6d68e8a711 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -558,6 +558,7 @@ struct vb2_buf_ops {
  * @dma_dir:	DMA mapping direction.
  * @bufs:	videobuf2 buffer structures
  * @num_buffers: number of allocated/used buffers
+ * @max_num_buffers: upper limit of number of allocated/used buffers
  * @queued_list: list of buffers currently queued from userspace
  * @queued_count: number of buffers queued and ready for streaming.
  * @owned_by_drv_count: number of buffers owned by the driver
@@ -619,8 +620,9 @@ struct vb2_queue {
 	struct mutex			mmap_lock;
 	unsigned int			memory;
 	enum dma_data_direction		dma_dir;
-	struct vb2_buffer		*bufs[VB2_MAX_FRAME];
+	struct vb2_buffer		**bufs;
 	unsigned int			num_buffers;
+	unsigned int			max_num_buffers;
 
 	struct list_head		queued_list;
 	unsigned int			queued_count;
-- 
2.39.2