[PATCH v2 2/8] media: videobuf2: Make bufs array dynamic allocated

[Benjamin Gaignard]

Instead of a static array change bufs to a dynamically allocated array.
This will allow to store more video buffer if needed.
Protect the array with a spinlock.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxxxxx>
---
 .../media/common/videobuf2/videobuf2-core.c   |  8 +++
 include/media/videobuf2-core.h                | 49 ++++++++++++++++---
 2 files changed, 49 insertions(+), 8 deletions(-)

diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
index 79e90e338846..ae9d72f4d181 100644
--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c
@@ -2452,6 +2452,13 @@ int vb2_core_queue_init(struct vb2_queue *q)
 	mutex_init(&q->mmap_lock);
 	init_waitqueue_head(&q->done_wq);
 
+	q->max_num_bufs = 32;
+	q->bufs = kmalloc_array(q->max_num_bufs, sizeof(*q->bufs), GFP_KERNEL | __GFP_ZERO);
+	if (!q->bufs)
+		return -ENOMEM;
+
+	spin_lock_init(&q->bufs_lock);
+
 	q->memory = VB2_MEMORY_UNKNOWN;
 
 	if (q->buf_struct_size == 0)
@@ -2479,6 +2486,7 @@ void vb2_core_queue_release(struct vb2_queue *q)
 	mutex_lock(&q->mmap_lock);
 	__vb2_queue_free(q, q->num_buffers);
 	mutex_unlock(&q->mmap_lock);
+	kfree(q->bufs);
 }
 EXPORT_SYMBOL_GPL(vb2_core_queue_release);
 
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index 5b1e3d801546..397dbf6e61e1 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -558,6 +558,8 @@ struct vb2_buf_ops {
  * @dma_dir:	DMA mapping direction.
  * @bufs:	videobuf2 buffer structures
  * @num_buffers: number of allocated/used buffers
+ * @bufs_lock: lock to protect bufs access
+ * @max_num_bufs: max number of buffers storable in bufs
  * @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 +621,10 @@ 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;
+	spinlock_t			bufs_lock;
+	size_t				max_num_bufs;
 
 	struct list_head		queued_list;
 	unsigned int			queued_count;
@@ -1239,9 +1243,16 @@ static inline void vb2_clear_last_buffer_dequeued(struct vb2_queue *q)
 static inline struct vb2_buffer *vb2_get_buffer(struct vb2_queue *q,
 						unsigned int index)
 {
-	if (index < q->num_buffers)
-		return q->bufs[index];
-	return NULL;
+	struct vb2_buffer *vb = NULL;
+
+	spin_lock(&q->bufs_lock);
+
+	if (index < q->max_num_bufs)
+		vb = q->bufs[index];
+
+	spin_unlock(&q->bufs_lock);
+
+	return vb;
 }
 
 /**
@@ -1251,12 +1262,30 @@ static inline struct vb2_buffer *vb2_get_buffer(struct vb2_queue *q,
  */
 static inline bool vb2_queue_add_buffer(struct vb2_queue *q, struct vb2_buffer *vb)
 {
-	if (vb->index < VB2_MAX_FRAME) {
+	bool ret = false;
+
+	spin_lock(&q->bufs_lock);
+
+	if (vb->index >= q->max_num_bufs) {
+		struct vb2_buffer **tmp;
+
+		tmp = krealloc_array(q->bufs, q->max_num_bufs * 2, sizeof(*q->bufs), GFP_KERNEL);
+		if (!tmp)
+			goto realloc_failed;
+
+		q->max_num_bufs *= 2;
+		q->bufs = tmp;
+	}
+
+	if (vb->index < q->max_num_bufs) {
 		q->bufs[vb->index] = vb;
-		return true;
+		ret = true;
 	}
 
-	return false;
+realloc_failed:
+	spin_unlock(&q->bufs_lock);
+
+	return ret;
 }
 
 /**
@@ -1266,8 +1295,12 @@ static inline bool vb2_queue_add_buffer(struct vb2_queue *q, struct vb2_buffer *
  */
 static inline void vb2_queue_remove_buffer(struct vb2_queue *q, struct vb2_buffer *vb)
 {
-	if (vb->index < VB2_MAX_FRAME)
+	spin_lock(&q->bufs_lock);
+
+	if (vb->index < q->max_num_bufs)
 		q->bufs[vb->index] = NULL;
+
+	spin_unlock(&q->bufs_lock);
 }
 
 /*
-- 
2.34.1