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Message-ID: <a3cde8de-1a7e-49bd-b7d4-8d9a7ed5beaa@xs4all.nl>
Date: Mon, 15 Jan 2024 17:08:34 +0100
From: Hans Verkuil <hverkuil@...all.nl>
To: Benjamin Gaignard <benjamin.gaignard@...labora.com>, mchehab@...nel.org
Cc: linux-kernel@...r.kernel.org, linux-media@...r.kernel.org,
kernel@...labora.com
Subject: Re: [PATCH v16 5/8] media: core: Free range of buffers
On 15/12/2023 10:08, Benjamin Gaignard wrote:
> Improve __vb2_queue_free() and __vb2_free_mem() to free
> range of buffers and not only the last few buffers.
> Intoduce starting index to be flexible on range and change the loops
> according to this parameters.
>
> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@...labora.com>
> ---
> .../media/common/videobuf2/videobuf2-core.c | 62 +++++++++----------
> 1 file changed, 30 insertions(+), 32 deletions(-)
>
> diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
> index 9509535a980c..67ce823a0196 100644
> --- a/drivers/media/common/videobuf2/videobuf2-core.c
> +++ b/drivers/media/common/videobuf2/videobuf2-core.c
> @@ -525,17 +525,16 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory,
> }
>
> /*
> - * __vb2_free_mem() - release all video buffer memory for a given queue
> + * __vb2_free_mem() - release video buffer memory for a given range of
> + * buffers in a given queue
> */
> -static void __vb2_free_mem(struct vb2_queue *q, unsigned int buffers)
> +static void __vb2_free_mem(struct vb2_queue *q, unsigned int start, unsigned int count)
> {
> - unsigned int buffer;
> + unsigned int i;
> struct vb2_buffer *vb;
> - unsigned int q_num_buffers = vb2_get_num_buffers(q);
>
> - for (buffer = q_num_buffers - buffers; buffer < q_num_buffers;
> - ++buffer) {
> - vb = vb2_get_buffer(q, buffer);
> + for (i = start; i < q->max_num_buffers && i < start + count; i++) {
I think the i < q->max_num_buffers check should be dropped. 'start + count'
should always be <= q->max_num_buffers. That's something that must be
checked in a higher level function.
> + vb = vb2_get_buffer(q, i);
> if (!vb)
> continue;
>
> @@ -550,35 +549,35 @@ static void __vb2_free_mem(struct vb2_queue *q, unsigned int buffers)
> }
>
> /*
> - * __vb2_queue_free() - free buffers at the end of the queue - video memory and
> + * __vb2_queue_free() - free @count buffers from @start index of the queue - video memory and
> * related information, if no buffers are left return the queue to an
> * uninitialized state. Might be called even if the queue has already been freed.
> */
> -static void __vb2_queue_free(struct vb2_queue *q, unsigned int buffers)
> +static void __vb2_queue_free(struct vb2_queue *q, unsigned int start, unsigned int count)
> {
> - unsigned int buffer;
> - unsigned int q_num_buffers = vb2_get_num_buffers(q);
> + unsigned int i;
>
> 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;
> - ++buffer) {
> - struct vb2_buffer *vb = vb2_get_buffer(q, buffer);
> + for (i = start; i < q->max_num_buffers && i < start + count; i++) {
Ditto, and also the various instances below.
> + struct vb2_buffer *vb = vb2_get_buffer(q, i);
>
> - if (vb && vb->planes[0].mem_priv)
> + if (!vb)
> + continue;> + if (vb->planes[0].mem_priv)
Why change this code?
> call_void_vb_qop(vb, buf_cleanup, vb);
> }
>
> /* Release video buffer memory */
> - __vb2_free_mem(q, buffers);
> + __vb2_free_mem(q, start, count);
>
> #ifdef CONFIG_VIDEO_ADV_DEBUG
> /*
> * 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 (vb2_get_num_buffers(q)) {
> 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;
> @@ -604,8 +603,8 @@ 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 < vb2_get_num_buffers(q); buffer++) {
> - struct vb2_buffer *vb = vb2_get_buffer(q, buffer);
> + for (i = start; i < q->max_num_buffers && i < start + count; i++) {
> + struct vb2_buffer *vb = vb2_get_buffer(q, i);
> bool unbalanced;
>
> if (!vb)
> @@ -622,7 +621,7 @@ static void __vb2_queue_free(struct vb2_queue *q, unsigned int buffers)
>
> if (unbalanced) {
> pr_info("unbalanced counters for queue %p, buffer %d:\n",
> - q, buffer);
> + q, i);
> if (vb->cnt_buf_init != vb->cnt_buf_cleanup)
> pr_info(" buf_init: %u buf_cleanup: %u\n",
> vb->cnt_buf_init, vb->cnt_buf_cleanup);
> @@ -656,9 +655,8 @@ 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;
> - ++buffer) {
> - struct vb2_buffer *vb = vb2_get_buffer(q, buffer);
> + for (i = start; i < q->max_num_buffers && i < start + count; i++) {
> + struct vb2_buffer *vb = vb2_get_buffer(q, i);
>
> if (!vb)
> continue;
> @@ -698,7 +696,7 @@ EXPORT_SYMBOL(vb2_buffer_in_use);
> static bool __buffers_in_use(struct vb2_queue *q)
> {
> unsigned int buffer;
> - for (buffer = 0; buffer < vb2_get_num_buffers(q); ++buffer) {
> + for (buffer = 0; buffer < q->max_num_buffers; ++buffer) {
> struct vb2_buffer *vb = vb2_get_buffer(q, buffer);
>
> if (!vb)
> @@ -858,7 +856,7 @@ 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_bufs);
> + __vb2_queue_free(q, 0, q->max_num_buffers);
> mutex_unlock(&q->mmap_lock);
>
> /*
> @@ -968,7 +966,7 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
> * from already queued buffers and it will reset q->memory to
> * VB2_MEMORY_UNKNOWN.
> */
> - __vb2_queue_free(q, allocated_buffers);
> + __vb2_queue_free(q, first_index, allocated_buffers);
> mutex_unlock(&q->mmap_lock);
> return ret;
> }
> @@ -1008,7 +1006,7 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
> bool no_previous_buffers = !q_num_bufs;
> int ret = 0;
>
> - if (q->num_buffers == q->max_num_buffers) {
> + if (q_num_bufs == q->max_num_buffers) {
> dprintk(q, 1, "maximum number of buffers already allocated\n");
> return -ENOBUFS;
> }
> @@ -1108,7 +1106,7 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
> * from already queued buffers and it will reset q->memory to
> * VB2_MEMORY_UNKNOWN.
> */
> - __vb2_queue_free(q, allocated_buffers);
> + __vb2_queue_free(q, *first_index, allocated_buffers);
> mutex_unlock(&q->mmap_lock);
> return -ENOMEM;
> }
> @@ -1722,7 +1720,7 @@ 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 < vb2_get_num_buffers(q); ++i) {
> + for (i = 0; i < q->max_num_buffers; ++i) {
> vb = vb2_get_buffer(q, i);
>
> if (!vb)
> @@ -2128,7 +2126,7 @@ 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 < vb2_get_num_buffers(q); i++) {
> + for (i = 0; i < q->max_num_buffers; i++) {
> struct vb2_buffer *vb = vb2_get_buffer(q, i);
>
> if (!vb)
> @@ -2172,7 +2170,7 @@ 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 < vb2_get_num_buffers(q); i++) {
> + for (i = 0; i < q->max_num_buffers; i++) {
> struct vb2_buffer *vb;
> struct media_request *req;
>
> @@ -2586,7 +2584,7 @@ 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, vb2_get_num_buffers(q));
> + __vb2_queue_free(q, 0, q->max_num_buffers);
> kfree(q->bufs);
> q->bufs = NULL;
> bitmap_free(q->bufs_bitmap);
Regards,
Hans
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