[PATCH v6 11/18] media: videobuf2: Be more flexible on the number of queue stored buffers
Benjamin Gaignard
benjamin.gaignard at collabora.com
Mon Sep 4 04:46:38 PDT 2023
Le 04/09/2023 à 13:24, Hans Verkuil a écrit :
> Hi Benjamin,
>
> On 01/09/2023 14:44, Benjamin Gaignard wrote:
>> Add 'max_allowed_buffers' field in vb2_queue struct to let drivers decide
>> how many buffers could be stored in a queue.
>> This request 'bufs' array to be allocated at queue init time and freed
>> when releasing the queue.
>> By default VB2_MAX_FRAME remains the limit.
>>
>> Signed-off-by: Benjamin Gaignard <benjamin.gaignard at collabora.com>
>> ---
>> .../media/common/videobuf2/videobuf2-core.c | 25 +++++++++++++------
>> include/media/videobuf2-core.h | 4 ++-
>> 2 files changed, 20 insertions(+), 9 deletions(-)
>>
> This patch breaks v4l2-compliance. I see lots of issues when running the
> test-media script in v4l-utils, contrib/test, among them memory leaks
> and use-after-free.
>
> I actually tested using virtme with the build scripts, but that in turn
> calls the test-media script in a qemu environment, and it is at the moment
> a bit tricky to set up, unless you run a debian 12 distro.
>
> I will email the test logs directly to you since they are a bit large (>5000 lines).
I will try to reproduce this error on my side to fix it.
Regards,
Benjamin
>
> Regards,
>
> Hans
>
>
>
>> diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
>> index 15b583ce0c69..dc7f6b59d237 100644
>> --- a/drivers/media/common/videobuf2/videobuf2-core.c
>> +++ b/drivers/media/common/videobuf2/videobuf2-core.c
>> @@ -411,7 +411,7 @@ static void init_buffer_cache_hints(struct vb2_queue *q, struct vb2_buffer *vb)
>> */
>> static bool vb2_queue_add_buffer(struct vb2_queue *q, struct vb2_buffer *vb, unsigned int index)
>> {
>> - if (index < VB2_MAX_FRAME && !q->bufs[index]) {
>> + if (index < q->max_allowed_buffers && !q->bufs[index]) {
>> q->bufs[index] = vb;
>> vb->index = index;
>> vb->vb2_queue = q;
>> @@ -428,7 +428,7 @@ static bool vb2_queue_add_buffer(struct vb2_queue *q, struct vb2_buffer *vb, uns
>> */
>> static void vb2_queue_remove_buffer(struct vb2_queue *q, struct vb2_buffer *vb)
>> {
>> - if (vb->index < VB2_MAX_FRAME) {
>> + if (vb->index < q->max_allowed_buffers) {
>> q->bufs[vb->index] = NULL;
>> vb->vb2_queue = NULL;
>> }
>> @@ -449,9 +449,9 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory,
>> struct vb2_buffer *vb;
>> int ret;
>>
>> - /* Ensure that q->num_buffers+num_buffers is below VB2_MAX_FRAME */
>> + /* Ensure that q->num_buffers+num_buffers is below q->max_allowed_buffers */
>> num_buffers = min_t(unsigned int, num_buffers,
>> - VB2_MAX_FRAME - q->num_buffers);
>> + q->max_allowed_buffers - q->num_buffers);
>>
>> for (buffer = 0; buffer < num_buffers; ++buffer) {
>> /* Allocate vb2 buffer structures */
>> @@ -862,9 +862,9 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
>> /*
>> * Make sure the requested values and current defaults are sane.
>> */
>> - WARN_ON(q->min_buffers_needed > VB2_MAX_FRAME);
>> + WARN_ON(q->min_buffers_needed > q->max_allowed_buffers);
>> num_buffers = max_t(unsigned int, *count, q->min_buffers_needed);
>> - num_buffers = min_t(unsigned int, num_buffers, VB2_MAX_FRAME);
>> + num_buffers = min_t(unsigned int, num_buffers, q->max_allowed_buffers);
>> memset(q->alloc_devs, 0, sizeof(q->alloc_devs));
>> /*
>> * Set this now to ensure that drivers see the correct q->memory value
>> @@ -980,7 +980,7 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
>> bool no_previous_buffers = !q->num_buffers;
>> int ret;
>>
>> - if (q->num_buffers == VB2_MAX_FRAME) {
>> + if (q->num_buffers == q->max_allowed_buffers) {
>> dprintk(q, 1, "maximum number of buffers already allocated\n");
>> return -ENOBUFS;
>> }
>> @@ -1009,7 +1009,7 @@ 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, q->max_allowed_buffers - q->num_buffers);
>>
>> if (requested_planes && requested_sizes) {
>> num_planes = requested_planes;
>> @@ -2519,6 +2519,14 @@ int vb2_core_queue_init(struct vb2_queue *q)
>>
>> q->memory = VB2_MEMORY_UNKNOWN;
>>
>> + if (!q->max_allowed_buffers)
>> + q->max_allowed_buffers = VB2_MAX_FRAME;
>> +
>> + /* The maximum is limited by offset cookie encoding pattern */
>> + q->max_allowed_buffers = min_t(unsigned int, q->max_allowed_buffers, BUFFER_INDEX_MASK);
>> +
>> + q->bufs = kcalloc(q->max_allowed_buffers, sizeof(*q->bufs), GFP_KERNEL);
>> +
>> if (q->buf_struct_size == 0)
>> q->buf_struct_size = sizeof(struct vb2_buffer);
>>
>> @@ -2543,6 +2551,7 @@ void vb2_core_queue_release(struct vb2_queue *q)
>> __vb2_queue_cancel(q);
>> mutex_lock(&q->mmap_lock);
>> __vb2_queue_free(q, q->num_buffers);
>> + kfree(q->bufs);
>> mutex_unlock(&q->mmap_lock);
>> }
>> EXPORT_SYMBOL_GPL(vb2_core_queue_release);
>> diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
>> index cd3ff1cd759d..97153c69583f 100644
>> --- a/include/media/videobuf2-core.h
>> +++ b/include/media/videobuf2-core.h
>> @@ -558,6 +558,7 @@ struct vb2_buf_ops {
>> * @dma_dir: DMA mapping direction.
>> * @bufs: videobuf2 buffer structures
>> * @num_buffers: number of allocated/used buffers
>> + * @max_allowed_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.
>> * @owned_by_drv_count: number of buffers owned by the driver
>> @@ -619,8 +620,9 @@ 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;
>> + unsigned int max_allowed_buffers;
>>
>> struct list_head queued_list;
>> unsigned int queued_count;
>
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