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SubjectRe: [RFC][PATCH 06/15] videobuf2: handle V4L2_FLAG_MEMORY_NON_CONSISTENT in CREATE_BUFS
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On 12/17/19 4:20 AM, Sergey Senozhatsky wrote:
> This patch lets user-space to request a non-consistent memory
> allocation during CREATE_BUFS ioctl call. struct v4l2_create_buffers
> has seven 4-byte reserved areas, so reserved[0] is renamed to ->flags.
> The struct, thus, now has six reserved 4-byte regions.
>
> Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
> ---
> .../media/uapi/v4l/vidioc-create-bufs.rst | 8 +++++-
> .../media/common/videobuf2/videobuf2-core.c | 27 +++++++++++++++----
> .../media/common/videobuf2/videobuf2-v4l2.c | 7 ++++-
> drivers/media/v4l2-core/v4l2-ioctl.c | 2 +-
> include/media/videobuf2-core.h | 4 ++-
> include/uapi/linux/videodev2.h | 3 ++-
> 6 files changed, 41 insertions(+), 10 deletions(-)
>
> diff --git a/Documentation/media/uapi/v4l/vidioc-create-bufs.rst b/Documentation/media/uapi/v4l/vidioc-create-bufs.rst
> index bd08e4f77ae4..c56e80659b4a 100644
> --- a/Documentation/media/uapi/v4l/vidioc-create-bufs.rst
> +++ b/Documentation/media/uapi/v4l/vidioc-create-bufs.rst
> @@ -121,7 +121,13 @@ than the number requested.
> other changes, then set ``count`` to 0, ``memory`` to
> ``V4L2_MEMORY_MMAP`` and ``format.type`` to the buffer type.
> * - __u32
> - - ``reserved``\ [7]
> + - ``flags``
> + - Specifies additional buffer management attributes. E.g. when
> + ``V4L2_FLAG_MEMORY_NON_CONSISTENT`` set vb2 backends may be allocated
> + in non-consistent memory.

Same comment as for patch 05/15.

> +
> + * - __u32
> + - ``reserved``\ [6]
> - A place holder for future extensions. Drivers and applications
> must set the array to zero.
>
> diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
> index 668c56df13f6..d1012a24755d 100644
> --- a/drivers/media/common/videobuf2/videobuf2-core.c
> +++ b/drivers/media/common/videobuf2/videobuf2-core.c
> @@ -812,9 +812,21 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
> }
> EXPORT_SYMBOL_GPL(vb2_core_reqbufs);
>
> +static bool verify_consistency_attr(struct vb2_queue *q, bool consistent_mem)
> +{
> + bool queue_attr = q->dma_attrs & DMA_ATTR_NON_CONSISTENT;
> +
> + if (consistent_mem != queue_attr) {
> + dprintk(1, "memory consistency model mismatch\n");
> + return false;
> + }
> + return true;
> +}
> +

This belongs in patch 04/15. The commit log for that patch makes a lot
more sense if this code is moved there.

> int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
> - unsigned int *count, unsigned requested_planes,
> - const unsigned requested_sizes[])
> + bool consistent_mem, unsigned int *count,
> + unsigned requested_planes,
> + const unsigned requested_sizes[])
> {
> unsigned int num_planes = 0, num_buffers, allocated_buffers;
> unsigned plane_sizes[VB2_MAX_PLANES] = { };
> @@ -832,10 +844,15 @@ int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
> }
> memset(q->alloc_devs, 0, sizeof(q->alloc_devs));
> q->memory = memory;
> + __set_queue_consistency(q, consistent_mem);
> q->waiting_for_buffers = !q->is_output;
> - } else if (q->memory != memory) {
> - dprintk(1, "memory model mismatch\n");
> - return -EINVAL;
> + } else {
> + if (q->memory != memory) {
> + dprintk(1, "memory model mismatch\n");
> + return -EINVAL;
> + }
> + if (!verify_consistency_attr(q, consistent_mem))
> + return -EINVAL;
> }

Ditto.

>
> num_buffers = min(*count, VB2_MAX_FRAME - q->num_buffers);
> diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
> index 0eabb589684f..48d123a1ac2a 100644
> --- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
> +++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
> @@ -730,6 +730,7 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
> unsigned requested_sizes[VIDEO_MAX_PLANES];
> struct v4l2_format *f = &create->format;
> int ret = vb2_verify_memory_type(q, create->memory, f->type);
> + bool consistent = true;
> unsigned i;
>
> fill_buf_caps(q, &create->capabilities);
> @@ -775,7 +776,11 @@ int vb2_create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create)
> for (i = 0; i < requested_planes; i++)
> if (requested_sizes[i] == 0)
> return -EINVAL;
> - return ret ? ret : vb2_core_create_bufs(q, create->memory,
> +
> + if (create->flags & V4L2_FLAG_MEMORY_NON_CONSISTENT)
> + consistent = false;
> +
> + return ret ? ret : vb2_core_create_bufs(q, create->memory, consistent,
> &create->count, requested_planes, requested_sizes);

As mentioned before: we need a V4L2_BUF_CAP capability.

> }
> EXPORT_SYMBOL_GPL(vb2_create_bufs);
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> index 225d06819bce..793cb6534de4 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -2012,7 +2012,7 @@ static int v4l_create_bufs(const struct v4l2_ioctl_ops *ops,
> if (ret)
> return ret;
>
> - CLEAR_AFTER_FIELD(create, capabilities);
> + CLEAR_AFTER_FIELD(create, flags);
>
> v4l_sanitize_format(&create->format);
>
> diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
> index 810af5cf5742..5e5450bdabbd 100644
> --- a/include/media/videobuf2-core.h
> +++ b/include/media/videobuf2-core.h
> @@ -757,6 +757,7 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
> * vb2_core_create_bufs() - Allocate buffers and any required auxiliary structs
> * @q: pointer to &struct vb2_queue with videobuf2 queue.
> * @memory: memory type, as defined by &enum vb2_memory.
> + * @consistent_mem: memory consistency model.
> * @count: requested buffer count.
> * @requested_planes: number of planes requested.
> * @requested_sizes: array with the size of the planes.
> @@ -774,7 +775,8 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
> * Return: returns zero on success; an error code otherwise.
> */
> int vb2_core_create_bufs(struct vb2_queue *q, enum vb2_memory memory,
> - unsigned int *count, unsigned int requested_planes,
> + bool consistent_mem, unsigned int *count,
> + unsigned int requested_planes,
> const unsigned int requested_sizes[]);
>
> /**
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index 73a4854f71bd..82e2ded5a136 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -2419,7 +2419,8 @@ struct v4l2_create_buffers {
> __u32 memory;
> struct v4l2_format format;
> __u32 capabilities;
> - __u32 reserved[7];
> + __u32 flags;
> + __u32 reserved[6];
> };
>
> /*
>

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