[PATCH v14 08/56] media: videobuf2: Use vb2_get_num_buffers() helper

Benjamin Gaignard
2023-10-31T16:32:38Z

Stop using queue num_buffers field directly, instead use
vb2_get_num_buffers().
This prepares for the future 'delete buffers' feature where there are
holes in the buffer indices.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
---
.../media/common/videobuf2/videobuf2-core.c | 92 +++++++++++--------
.../media/common/videobuf2/videobuf2-v4l2.c | 4 +-
2 files changed, 54 insertions(+), 42 deletions(-)

diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
index b406a30a9b35..c5c5ae4d213d 100644
--- a/drivers/media/common/videobuf2/videobuf2-core.c
+++ b/drivers/media/common/videobuf2/videobuf2-core.c
@@ -444,13 +444,14 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory,
unsigned int num_buffers, unsigned int num_planes,
const unsigned plane_sizes[VB2_MAX_PLANES])
{
+ unsigned int q_num_buffers = vb2_get_num_buffers(q);
unsigned int buffer, plane;
struct vb2_buffer *vb;
int ret;

/* Ensure that q->num_buffers+num_buffers is below VB2_MAX_FRAME */
num_buffers = min_t(unsigned int, num_buffers,
- VB2_MAX_FRAME - q->num_buffers);
+ VB2_MAX_FRAME - q_num_buffers);

for (buffer = 0; buffer < num_buffers; ++buffer) {
/* Allocate vb2 buffer structures */
@@ -470,7 +471,7 @@ 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, q_num_buffers + buffer);
call_void_bufop(q, init_buffer, vb);

/* Allocate video buffer memory for the MMAP type */
@@ -514,8 +515,9 @@ static void __vb2_free_mem(struct vb2_queue *q, unsigned int buffers)
{
unsigned int buffer;
struct vb2_buffer *vb;
+ unsigned int q_num_buffers = vb2_get_num_buffers(q);

- for (buffer = q->num_buffers - buffers; buffer < q->num_buffers;
+ for (buffer = q_num_buffers - buffers; buffer < q_num_buffers;
++buffer) {
vb = vb2_get_buffer(q, buffer);
if (!vb)
@@ -539,11 +541,12 @@ static void __vb2_free_mem(struct vb2_queue *q, unsigned int buffers)
static void __vb2_queue_free(struct vb2_queue *q, unsigned int buffers)
{
unsigned int buffer;
+ unsigned int q_num_buffers = vb2_get_num_buffers(q);

lockdep_assert_held(&q->mmap_lock);

/* Call driver-provided cleanup function for each buffer, if provided */
- for (buffer = q->num_buffers - buffers; buffer < q->num_buffers;
+ for (buffer = q_num_buffers - buffers; buffer < q_num_buffers;
++buffer) {
struct vb2_buffer *vb = vb2_get_buffer(q, buffer);

@@ -559,7 +562,7 @@ static void __vb2_queue_free(struct vb2_queue *q, unsigned int buffers)
* Check that all the calls were balanced during the life-time of this
* queue. If not then dump the counters to the kernel log.
*/
- if (q->num_buffers) {
+ if (q_num_buffers) {
bool unbalanced = q->cnt_start_streaming != q->cnt_stop_streaming ||
q->cnt_prepare_streaming != q->cnt_unprepare_streaming ||
q->cnt_wait_prepare != q->cnt_wait_finish;
@@ -585,7 +588,7 @@ static void __vb2_queue_free(struct vb2_queue *q, unsigned int buffers)
q->cnt_stop_streaming = 0;
q->cnt_unprepare_streaming = 0;
}
- for (buffer = 0; buffer < q->num_buffers; ++buffer) {
+ for (buffer = 0; buffer < vb2_get_num_buffers(q); buffer++) {
struct vb2_buffer *vb = vb2_get_buffer(q, buffer);
bool unbalanced;

@@ -637,7 +640,7 @@ static void __vb2_queue_free(struct vb2_queue *q, unsigned int buffers)
#endif

/* Free vb2 buffers */
- for (buffer = q->num_buffers - buffers; buffer < q->num_buffers;
+ for (buffer = q_num_buffers - buffers; buffer < q_num_buffers;
++buffer) {
struct vb2_buffer *vb = vb2_get_buffer(q, buffer);

@@ -649,7 +652,7 @@ static void __vb2_queue_free(struct vb2_queue *q, unsigned int buffers)
}

q->num_buffers -= buffers;
- if (!q->num_buffers) {
+ if (!vb2_get_num_buffers(q)) {
q->memory = VB2_MEMORY_UNKNOWN;
INIT_LIST_HEAD(&q->queued_list);
}
@@ -680,7 +683,7 @@ EXPORT_SYMBOL(vb2_buffer_in_use);
static bool __buffers_in_use(struct vb2_queue *q)
{
unsigned int buffer;
- for (buffer = 0; buffer < q->num_buffers; ++buffer) {
+ for (buffer = 0; buffer < vb2_get_num_buffers(q); ++buffer) {
struct vb2_buffer *vb = vb2_get_buffer(q, buffer);

if (!vb)
@@ -806,6 +809,7 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
unsigned int flags, unsigned int *count)
{
unsigned int num_buffers, allocated_buffers, num_planes = 0;
+ unsigned int q_num_bufs = vb2_get_num_buffers(q);
unsigned plane_sizes[VB2_MAX_PLANES] = { };
bool non_coherent_mem = flags & V4L2_MEMORY_FLAG_NON_COHERENT;
unsigned int i;
@@ -821,7 +825,7 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
return -EBUSY;
}

- if (*count == 0 || q->num_buffers != 0 ||
+ if (*count == 0 || q_num_bufs != 0 ||
(q->memory != VB2_MEMORY_UNKNOWN && q->memory != memory) ||
!verify_coherency_flags(q, non_coherent_mem)) {
/*
@@ -839,7 +843,7 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
* queued without ever calling STREAMON.
*/
__vb2_queue_cancel(q);
- __vb2_queue_free(q, q->num_buffers);
+ __vb2_queue_free(q, q_num_bufs);
mutex_unlock(&q->mmap_lock);

/*
@@ -934,7 +938,7 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
if (ret < 0) {
/*
* Note: __vb2_queue_free() will subtract 'allocated_buffers'
- * from q->num_buffers and it will reset q->memory to
+ * from already queued buffers and it will reset q->memory to
* VB2_MEMORY_UNKNOWN.
*/
__vb2_queue_free(q, allocated_buffers);
@@ -968,10 +972,11 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
unsigned int num_planes = 0, num_buffers, allocated_buffers;
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;
+ unsigned int q_num_bufs = vb2_get_num_buffers(q);
+ bool no_previous_buffers = !q_num_bufs;
+ int ret = 0;

- if (q->num_buffers == VB2_MAX_FRAME) {
+ if (q_num_bufs == VB2_MAX_FRAME) {
dprintk(q, 1, "maximum number of buffers already allocated\n");
return -ENOBUFS;
}
@@ -1000,7 +1005,7 @@ 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, VB2_MAX_FRAME - q_num_bufs);

if (requested_planes && requested_sizes) {
num_planes = requested_planes;
@@ -1032,7 +1037,7 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
num_buffers = allocated_buffers;

/*
- * q->num_buffers contains the total number of buffers, that the
+ * num_buffers contains the total number of buffers, that the
* queue driver has set up
*/
ret = call_qop(q, queue_setup, q, &num_buffers,
@@ -1053,7 +1058,7 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
if (ret < 0) {
/*
* Note: __vb2_queue_free() will subtract 'allocated_buffers'
- * from q->num_buffers and it will reset q->memory to
+ * from already queued buffers and it will reset q->memory to
* VB2_MEMORY_UNKNOWN.
*/
__vb2_queue_free(q, allocated_buffers);
@@ -1670,7 +1675,7 @@ static int vb2_start_streaming(struct vb2_queue *q)
* Forcefully reclaim buffers if the driver did not
* correctly return them to vb2.
*/
- for (i = 0; i < q->num_buffers; ++i) {
+ for (i = 0; i < vb2_get_num_buffers(q); ++i) {
vb = vb2_get_buffer(q, i);

if (!vb)
@@ -2076,7 +2081,7 @@ static void __vb2_queue_cancel(struct vb2_queue *q)
* to vb2 in stop_streaming().
*/
if (WARN_ON(atomic_read(&q->owned_by_drv_count))) {
- for (i = 0; i < q->num_buffers; ++i) {
+ for (i = 0; i < vb2_get_num_buffers(q); i++) {
struct vb2_buffer *vb = vb2_get_buffer(q, i);

if (!vb)
@@ -2120,7 +2125,7 @@ static void __vb2_queue_cancel(struct vb2_queue *q)
* call to __fill_user_buffer() after buf_finish(). That order can't
* be changed, so we can't move the buf_finish() to __vb2_dqbuf().
*/
- for (i = 0; i < q->num_buffers; ++i) {
+ for (i = 0; i < vb2_get_num_buffers(q); i++) {
struct vb2_buffer *vb;
struct media_request *req;

@@ -2168,6 +2173,7 @@ static void __vb2_queue_cancel(struct vb2_queue *q)

int vb2_core_streamon(struct vb2_queue *q, unsigned int type)
{
+ unsigned int q_num_bufs = vb2_get_num_buffers(q);
int ret;

if (type != q->type) {
@@ -2180,12 +2186,12 @@ int vb2_core_streamon(struct vb2_queue *q, unsigned int type)
return 0;
}

- if (!q->num_buffers) {
+ if (!q_num_bufs) {
dprintk(q, 1, "no buffers have been allocated\n");
return -EINVAL;
}

- if (q->num_buffers < q->min_buffers_needed) {
+ if (q_num_bufs < q->min_buffers_needed) {
dprintk(q, 1, "need at least %u allocated buffers\n",
q->min_buffers_needed);
return -EINVAL;
@@ -2513,7 +2519,8 @@ void vb2_core_queue_release(struct vb2_queue *q)
__vb2_cleanup_fileio(q);
__vb2_queue_cancel(q);
mutex_lock(&q->mmap_lock);
- __vb2_queue_free(q, q->num_buffers);
+ __vb2_queue_free(q, vb2_get_num_buffers(q));
+ q->num_buffers = 0;
mutex_unlock(&q->mmap_lock);
}
EXPORT_SYMBOL_GPL(vb2_core_queue_release);
@@ -2542,7 +2549,7 @@ __poll_t vb2_core_poll(struct vb2_queue *q, struct file *file,
/*
* Start file I/O emulator only if streaming API has not been used yet.
*/
- if (q->num_buffers == 0 && !vb2_fileio_is_active(q)) {
+ if (vb2_get_num_buffers(q) == 0 && !vb2_fileio_is_active(q)) {
if (!q->is_output && (q->io_modes & VB2_READ) &&
(req_events & (EPOLLIN | EPOLLRDNORM))) {
if (__vb2_init_fileio(q, 1))
@@ -2580,7 +2587,7 @@ __poll_t vb2_core_poll(struct vb2_queue *q, struct file *file,
* For output streams you can call write() as long as there are fewer
* buffers queued than there are buffers available.
*/
- if (q->is_output && q->fileio && q->queued_count < q->num_buffers)
+ if (q->is_output && q->fileio && q->queued_count < vb2_get_num_buffers(q))
return EPOLLOUT | EPOLLWRNORM;

if (list_empty(&q->done_list)) {
@@ -2629,8 +2636,8 @@ struct vb2_fileio_buf {
* struct vb2_fileio_data - queue context used by file io emulator
*
* @cur_index: the index of the buffer currently being read from or
- * written to. If equal to q->num_buffers then a new buffer
- * must be dequeued.
+ * written to. If equal to number of already queued buffers
+ * then a new buffer must be dequeued.
* @initial_index: in the read() case all buffers are queued up immediately
* in __vb2_init_fileio() and __vb2_perform_fileio() just cycles
* buffers. However, in the write() case no buffers are initially
@@ -2640,7 +2647,7 @@ struct vb2_fileio_buf {
* buffers. This means that initially __vb2_perform_fileio()
* needs to know what buffer index to use when it is queuing up
* the buffers for the first time. That initial index is stored
- * in this field. Once it is equal to q->num_buffers all
+ * in this field. Once it is equal to num_buffers all
* available buffers have been queued and __vb2_perform_fileio()
* should start the normal dequeue/queue cycle.
*
@@ -2690,7 +2697,7 @@ static int __vb2_init_fileio(struct vb2_queue *q, int read)
/*
* Check if streaming api has not been already activated.
*/
- if (q->streaming || q->num_buffers > 0)
+ if (q->streaming || vb2_get_num_buffers(q) > 0)
return -EBUSY;

/*
@@ -2740,7 +2747,7 @@ static int __vb2_init_fileio(struct vb2_queue *q, int read)
/*
* Get kernel address of each buffer.
*/
- for (i = 0; i < q->num_buffers; i++) {
+ for (i = 0; i < vb2_get_num_buffers(q); i++) {
/* vb can never be NULL when using fileio. */
vb = vb2_get_buffer(q, i);

@@ -2759,18 +2766,23 @@ 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, q->bufs[i], NULL, NULL);
+ for (i = 0; i < vb2_get_num_buffers(q); i++) {
+ struct vb2_buffer *vb2 = vb2_get_buffer(q, i);
+
+ if (!vb2)
+ continue;
+
+ ret = vb2_core_qbuf(q, vb2, NULL, NULL);
if (ret)
goto err_reqbufs;
fileio->bufs[i].queued = 1;
}
/*
* All buffers have been queued, so mark that by setting
- * initial_index to q->num_buffers
+ * initial_index to num_buffers
*/
- fileio->initial_index = q->num_buffers;
- fileio->cur_index = q->num_buffers;
+ fileio->initial_index = vb2_get_num_buffers(q);
+ fileio->cur_index = fileio->initial_index;
}

/*
@@ -2964,12 +2976,12 @@ static size_t __vb2_perform_fileio(struct vb2_queue *q, char __user *data, size_
* If we are queuing up buffers for the first time, then
* increase initial_index by one.
*/
- if (fileio->initial_index < q->num_buffers)
+ if (fileio->initial_index < vb2_get_num_buffers(q))
fileio->initial_index++;
/*
* The next buffer to use is either a buffer that's going to be
- * queued for the first time (initial_index < q->num_buffers)
- * or it is equal to q->num_buffers, meaning that the next
+ * queued for the first time (initial_index < num_buffers)
+ * or it is equal to num_buffers, meaning that the next
* time we need to dequeue a buffer since we've now queued up
* all the 'first time' buffers.
*/
@@ -3016,7 +3028,7 @@ static int vb2_thread(void *data)
int ret = 0;

if (q->is_output) {
- prequeue = q->num_buffers;
+ prequeue = vb2_get_num_buffers(q);
copy_timestamp = q->copy_timestamp;
}

diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
index c6ebc8d2c537..7d798fb15c0b 100644
--- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
+++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
@@ -627,7 +627,7 @@ struct vb2_buffer *vb2_find_buffer(struct vb2_queue *q, u64 timestamp)
* This loop doesn't scale if there is a really large number of buffers.
* Maybe something more efficient will be needed in this case.
*/
- for (i = 0; i < q->num_buffers; i++) {
+ for (i = 0; i < vb2_get_num_buffers(q); i++) {
vb2 = vb2_get_buffer(q, i);

if (!vb2)
@@ -761,7 +761,7 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)

fill_buf_caps(q, &create->capabilities);
validate_memory_flags(q, create->memory, &create->flags);
- create->index = q->num_buffers;
+ create->index = vb2_get_num_buffers(q);
if (create->count == 0)
return ret != -EBUSY ? ret : 0;

--
2.39.2