Commit a286b083 authored by Benjamin Gaignard's avatar Benjamin Gaignard Committed by Hans Verkuil
Browse files

media: core: Add bitmap manage bufs array entries 



Add a bitmap field to know which of bufs array entries are
used or not.
Remove no more used num_buffers field from queue structure.
Use bitmap_find_next_zero_area() to find the first possible
range when creating new buffers to fill the gaps.
If no suitable range is found try to allocate less buffers
than requested.

Signed-off-by: default avatarBenjamin Gaignard <benjamin.gaignard@collabora.com>
Acked-by: default avatarMauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: default avatarHans Verkuil <hverkuil-cisco@xs4all.nl>
parent 6e423b75

drivers/media/common/videobuf2/videobuf2-core.c

+53 −18
Original line number Diff line number Diff line
@@ -421,11 +421,12 @@ 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 >= q->max_num_buffers || q->bufs[index] || vb->vb2_queue);

	WARN_ON(index >= q->max_num_buffers || test_bit(index, q->bufs_bitmap) || vb->vb2_queue);



	q->bufs[index] = vb;

	vb->index = index;

	vb->vb2_queue = q;

	set_bit(index, q->bufs_bitmap);

}



/**
@@ -434,6 +435,7 @@ static void vb2_queue_add_buffer(struct vb2_queue *q, struct vb2_buffer *vb, uns 
 */

static void vb2_queue_remove_buffer(struct vb2_buffer *vb)

{

	clear_bit(vb->index, vb->vb2_queue->bufs_bitmap);

	vb->vb2_queue->bufs[vb->index] = NULL;

	vb->vb2_queue = NULL;

}
@@ -452,9 +454,9 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory, 
			     const unsigned int plane_sizes[VB2_MAX_PLANES],

			     unsigned int *first_index)

{

	unsigned int q_num_buffers = vb2_get_num_buffers(q);

	unsigned int buffer, plane;

	struct vb2_buffer *vb;

	unsigned long index = q->max_num_buffers;

	int ret;



	/*
@@ -462,9 +464,25 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory, 
	 * in the queue is below q->max_num_buffers

	 */

	num_buffers = min_t(unsigned int, num_buffers,

			    q->max_num_buffers - q_num_buffers);

			    q->max_num_buffers - vb2_get_num_buffers(q));



	while (num_buffers) {

		index = bitmap_find_next_zero_area(q->bufs_bitmap, q->max_num_buffers,

						   0, num_buffers, 0);



		if (index < q->max_num_buffers)

			break;

		/* Try to find free space for less buffers */

		num_buffers--;

	}



	*first_index = q_num_buffers;

	/* If there is no space left to allocate buffers return 0 to indicate the error */

	if (!num_buffers) {

		*first_index = 0;

		return 0;

	}



	*first_index = index;



	for (buffer = 0; buffer < num_buffers; ++buffer) {

		/* Allocate vb2 buffer structures */
@@ -484,7 +502,7 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory, 
			vb->planes[plane].min_length = plane_sizes[plane];

		}



		vb2_queue_add_buffer(q, vb, q_num_buffers + buffer);

		vb2_queue_add_buffer(q, vb, index++);

		call_void_bufop(q, init_buffer, vb);



		/* Allocate video buffer memory for the MMAP type */
@@ -664,7 +682,6 @@ static void __vb2_queue_free(struct vb2_queue *q, unsigned int buffers) 
		kfree(vb);

	}



	q->num_buffers -= buffers;

	if (!vb2_get_num_buffers(q)) {

		q->memory = VB2_MEMORY_UNKNOWN;

		INIT_LIST_HEAD(&q->queued_list);
@@ -818,6 +835,32 @@ static bool verify_coherency_flags(struct vb2_queue *q, bool non_coherent_mem) 
	return true;

}



static int vb2_core_allocated_buffers_storage(struct vb2_queue *q)

{

	if (!q->bufs)

		q->bufs = kcalloc(q->max_num_buffers, sizeof(*q->bufs), GFP_KERNEL);

	if (!q->bufs)

		return -ENOMEM;



	if (!q->bufs_bitmap)

		q->bufs_bitmap = bitmap_zalloc(q->max_num_buffers, GFP_KERNEL);

	if (!q->bufs_bitmap) {

		kfree(q->bufs);

		q->bufs = NULL;

		return -ENOMEM;

	}



	return 0;

}



static void vb2_core_free_buffers_storage(struct vb2_queue *q)

{

	kfree(q->bufs);

	q->bufs = NULL;

	bitmap_free(q->bufs_bitmap);

	q->bufs_bitmap = NULL;

}



int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,

		     unsigned int flags, unsigned int *count)

{
@@ -879,10 +922,7 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory, 
	 * 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;

	ret = vb2_core_allocated_buffers_storage(q);

	q->memory = memory;

	mutex_unlock(&q->mmap_lock);

	if (ret)
@@ -954,7 +994,6 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory, 
	}



	mutex_lock(&q->mmap_lock);

	q->num_buffers = allocated_buffers;



	if (ret < 0) {

		/*
@@ -982,6 +1021,7 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory, 
	mutex_lock(&q->mmap_lock);

	q->memory = VB2_MEMORY_UNKNOWN;

	mutex_unlock(&q->mmap_lock);

	vb2_core_free_buffers_storage(q);

	return ret;

}

EXPORT_SYMBOL_GPL(vb2_core_reqbufs);
@@ -1015,11 +1055,8 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory, 
		 * value in the queue_setup op.

		 */

		mutex_lock(&q->mmap_lock);

		ret = vb2_core_allocated_buffers_storage(q);

		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;
@@ -1082,7 +1119,6 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory, 
	}



	mutex_lock(&q->mmap_lock);

	q->num_buffers += allocated_buffers;



	if (ret < 0) {

		/*
@@ -2583,8 +2619,7 @@ void vb2_core_queue_release(struct vb2_queue *q) 
	__vb2_queue_cancel(q);

	mutex_lock(&q->mmap_lock);

	__vb2_queue_free(q, vb2_get_num_buffers(q));

	kfree(q->bufs);

	q->bufs = NULL;

	vb2_core_free_buffers_storage(q);

	q->is_busy = 0;

	mutex_unlock(&q->mmap_lock);

}

include/media/videobuf2-core.h

+11 −7
Original line number Diff line number Diff line
@@ -346,8 +346,8 @@ struct vb2_buffer { 
 *			describes the requested number of planes and sizes\[\]

 *			contains the requested plane sizes. In this case

 *			\*num_buffers are being allocated additionally to

 *			q->num_buffers. If either \*num_planes or the requested

 *			sizes are invalid callback must return %-EINVAL.

 *			the buffers already allocated. If either \*num_planes

 *			or the requested sizes are invalid callback must return %-EINVAL.

 * @wait_prepare:	release any locks taken while calling vb2 functions;

 *			it is called before an ioctl needs to wait for a new

 *			buffer to arrive; required to avoid a deadlock in
@@ -571,8 +571,9 @@ struct vb2_buf_ops { 
 * @mmap_lock:	private mutex used when buffers are allocated/freed/mmapped

 * @memory:	current memory type used

 * @dma_dir:	DMA mapping direction.

 * @bufs:	videobuf2 buffer structures

 * @num_buffers: number of allocated/used buffers

 * @bufs:	videobuf2 buffer structures. If it is non-NULL then

 *		bufs_bitmap is also non-NULL.

 * @bufs_bitmap: bitmap tracking whether each bufs[] entry is used

 * @max_num_buffers: upper limit of number of allocated/used buffers.

 *		     If set to 0 v4l2 core will change it VB2_MAX_FRAME

 *		     for backward compatibility.
@@ -643,7 +644,7 @@ struct vb2_queue { 
	unsigned int			memory;

	enum dma_data_direction		dma_dir;

	struct vb2_buffer		**bufs;

	unsigned int			num_buffers;

	unsigned long			*bufs_bitmap;

	unsigned int			max_num_buffers;



	struct list_head		queued_list;
@@ -1173,7 +1174,10 @@ static inline bool vb2_fileio_is_active(struct vb2_queue *q) 
 */

static inline unsigned int vb2_get_num_buffers(struct vb2_queue *q)

{

	return q->num_buffers;

	if (q->bufs_bitmap)

		return bitmap_weight(q->bufs_bitmap, q->max_num_buffers);



	return 0;

}



/**
@@ -1282,7 +1286,7 @@ static inline struct vb2_buffer *vb2_get_buffer(struct vb2_queue *q, 
	if (index >= q->max_num_buffers)

		return NULL;



	if (index < q->num_buffers)

	if (test_bit(index, q->bufs_bitmap))

		return q->bufs[index];

	return NULL;

}