[PATCH v8 49/53] media: core: Add bitmap manage bufs array entries

Benjamin Gaignard
2023-09-27T15:40:54Z

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.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
---
.../media/common/videobuf2/videobuf2-core.c | 40 +++++++++++++++----
include/media/videobuf2-core.h | 19 ++++++---
2 files changed, 47 insertions(+), 12 deletions(-)

diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
index b5a963030cde..8d35cf7cef42 100644
--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c
@@ -415,11 +415,12 @@ 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]);
+ WARN_ON(index >= q->max_num_buffers || test_bit(index, q->bufs_bitmap));

q->bufs[index] = vb;
vb->index = index;
vb->vb2_queue = q;
+ set_bit(index, q->bufs_bitmap);
}

/**
@@ -428,6 +429,7 @@ 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;
}
@@ -449,11 +451,12 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory,
unsigned long index;
int ret;

- /* Ensure that the number of already queue + num_buffers is below q->max_num_buffers */
+ /* Ensure that vb2_get_num_buffers(q) + num_buffers is no more than q->max_num_buffers */
num_buffers = min_t(unsigned int, num_buffers,
q->max_num_buffers - vb2_get_num_buffers(q));

- index = vb2_get_num_buffers(q);
+ index = bitmap_find_next_zero_area(q->bufs_bitmap, q->max_num_buffers,
+ 0, num_buffers, 0);

*first_index = index;

@@ -875,6 +878,14 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
q->bufs = kcalloc(q->max_num_buffers, sizeof(*q->bufs), GFP_KERNEL);
if (!q->bufs)
ret = -ENOMEM;
+
+ if (!q->bufs_bitmap)
+ q->bufs_bitmap = bitmap_zalloc(q->max_num_buffers, GFP_KERNEL);
+ if (!q->bufs_bitmap) {
+ ret = -ENOMEM;
+ kfree(q->bufs);
+ q->bufs = NULL;
+ }
q->memory = memory;
mutex_unlock(&q->mmap_lock);
if (ret)
@@ -944,7 +955,6 @@ 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) {
/*
@@ -971,6 +981,10 @@ 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);
+ kfree(q->bufs);
+ q->bufs = NULL;
+ bitmap_free(q->bufs_bitmap);
+ q->bufs_bitmap = NULL;
return ret;
}
EXPORT_SYMBOL_GPL(vb2_core_reqbufs);
@@ -1007,9 +1021,19 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
q->memory = memory;
if (!q->bufs)
q->bufs = kcalloc(q->max_num_buffers, sizeof(*q->bufs), GFP_KERNEL);
- if (!q->bufs)
+ if (!q->bufs) {
ret = -ENOMEM;
+ goto unlock;
+ }
+ if (!q->bufs_bitmap)
+ q->bufs_bitmap = bitmap_zalloc(q->max_num_buffers, GFP_KERNEL);
+ if (!q->bufs_bitmap) {
+ ret = -ENOMEM;
+ kfree(q->bufs);
+ q->bufs = NULL;
+ }
mutex_unlock(&q->mmap_lock);
+unlock:
if (ret)
return ret;
q->waiting_for_buffers = !q->is_output;
@@ -1071,7 +1095,6 @@ 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) {
/*
@@ -2548,6 +2571,9 @@ void vb2_core_queue_release(struct vb2_queue *q)
__vb2_queue_free(q, q->max_num_buffers);
kfree(q->bufs);
q->bufs = NULL;
+ bitmap_free(q->bufs_bitmap);
+ q->bufs_bitmap = NULL;
+
mutex_unlock(&q->mmap_lock);
}
EXPORT_SYMBOL_GPL(vb2_core_queue_release);
@@ -2902,7 +2928,7 @@ static size_t __vb2_perform_fileio(struct vb2_queue *q, char __user *data, size_
* Check if we need to dequeue the buffer.
*/
index = fileio->cur_index;
- if (index >= q->num_buffers) {
+ if (!test_bit(index, q->bufs_bitmap)) {
struct vb2_buffer *b;

/*
diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index d433bf84e30c..fc1fcd8faa64 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -346,7 +346,7 @@ 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
+ * queue buffers. 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
@@ -557,7 +557,7 @@ struct vb2_buf_ops {
* @memory: current memory type used
* @dma_dir: DMA mapping direction.
* @bufs: videobuf2 buffer structures
- * @num_buffers: number of allocated/used buffers
+ * @bufs_bitmap: bitmap to manage bufs entries.
* @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.
@@ -621,7 +621,7 @@ 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;
@@ -1150,7 +1150,10 @@ 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 0;
+
+ return bitmap_weight(q->bufs_bitmap, q->max_num_buffers);
}

/**
@@ -1253,7 +1256,13 @@ 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)
+ if (!q->bufs_bitmap)
+ return NULL;
+
+ if (index >= q->max_num_buffers)
+ return NULL;
+
+ if (test_bit(index, q->bufs_bitmap))
return q->bufs[index];
return NULL;