Re: [PATCHv4 04/11] videobuf2: add queue memory consistency parameter

From: Hans Verkuil
Date: Fri Mar 06 2020 - 09:04:53 EST

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In reply to: Sergey Senozhatsky: "[PATCHv4 04/11] videobuf2: add queue memory consistency parameter"
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On 02/03/2020 05:12, Sergey Senozhatsky wrote:
> Preparations for future V4L2_FLAG_MEMORY_NON_CONSISTENT support.
>
> Extend vb2_core_reqbufs() with queue memory consistency flag
> that is applied to the newly allocated buffers.
>
> An attempt to allocate a buffer with consistency requirements
> which don't match queue's consistency model will fail.
>
> Signed-off-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
> ---
> .../media/common/videobuf2/videobuf2-core.c | 47 +++++++++++++++----
> .../media/common/videobuf2/videobuf2-v4l2.c | 6 +--
> drivers/media/dvb-core/dvb_vb2.c | 2 +-
> include/media/videobuf2-core.h | 7 ++-
> 4 files changed, 47 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
> index 4489744fbbd9..3ca0545db7ee 100644
> --- a/drivers/media/common/videobuf2/videobuf2-core.c
> +++ b/drivers/media/common/videobuf2/videobuf2-core.c
> @@ -664,8 +664,19 @@ int vb2_verify_memory_type(struct vb2_queue *q,
> }
> EXPORT_SYMBOL(vb2_verify_memory_type);
>
> +static void set_queue_consistency(struct vb2_queue *q, bool consistent_mem)
> +{
> + if (!vb2_queue_allows_cache_hints(q))
> + return;
> +
> + if (consistent_mem)
> + q->dma_attrs &= ~DMA_ATTR_NON_CONSISTENT;
> + else
> + q->dma_attrs |= DMA_ATTR_NON_CONSISTENT;
> +}
> +
> int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
> - unsigned int *count)
> + bool consistent_mem, unsigned int *count)
> {
> unsigned int num_buffers, allocated_buffers, num_planes = 0;
> unsigned plane_sizes[VB2_MAX_PLANES] = { };
> @@ -720,6 +731,7 @@ int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
> num_buffers = min_t(unsigned int, num_buffers, VB2_MAX_FRAME);
> memset(q->alloc_devs, 0, sizeof(q->alloc_devs));
> q->memory = memory;
> + set_queue_consistency(q, consistent_mem);
>
> /*
> * Ask the driver how many buffers and planes per buffer it requires.
> @@ -803,9 +815,21 @@ 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) {

This is the wrong way around!

It's much better to write it like this:

bool queue_is_consistent = !(q->dma_attrs & DMA_ATTR_NON_CONSISTENT);

if (consistent_mem != queue_is_consistent) {

What concerns me more is that this means that this series has not been
tested properly. I found this when testing with v4l2-compliance and vivid.

I'll reply to the cover letter with more information about what needs to be
done before I merge this.

> + dprintk(1, "memory consistency model mismatch\n");
> + return false;
> + }
> + return true;
> +}
> +
> 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[])

Use 'unsigned int' in the two lines above, as per checkpatch suggestion.

Regards,

Hans

> {
> unsigned int num_planes = 0, num_buffers, allocated_buffers;
> unsigned plane_sizes[VB2_MAX_PLANES] = { };
> @@ -823,10 +847,15 @@ 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;
> }
>
> num_buffers = min(*count, VB2_MAX_FRAME - q->num_buffers);
> @@ -2498,7 +2527,7 @@ static int __vb2_init_fileio(struct vb2_queue *q, int read)
> fileio->memory = VB2_MEMORY_MMAP;
> fileio->type = q->type;
> q->fileio = fileio;
> - ret = vb2_core_reqbufs(q, fileio->memory, &fileio->count);
> + ret = vb2_core_reqbufs(q, fileio->memory, true, &fileio->count);
> if (ret)
> goto err_kfree;
>
> @@ -2555,7 +2584,7 @@ static int __vb2_init_fileio(struct vb2_queue *q, int read)
>
> err_reqbufs:
> fileio->count = 0;
> - vb2_core_reqbufs(q, fileio->memory, &fileio->count);
> + vb2_core_reqbufs(q, fileio->memory, true, &fileio->count);
>
> err_kfree:
> q->fileio = NULL;
> @@ -2575,7 +2604,7 @@ static int __vb2_cleanup_fileio(struct vb2_queue *q)
> vb2_core_streamoff(q, q->type);
> q->fileio = NULL;
> fileio->count = 0;
> - vb2_core_reqbufs(q, fileio->memory, &fileio->count);
> + vb2_core_reqbufs(q, fileio->memory, true, &fileio->count);
> kfree(fileio);
> dprintk(3, "file io emulator closed\n");
> }
> diff --git a/drivers/media/common/videobuf2/videobuf2-v4l2.c b/drivers/media/common/videobuf2/videobuf2-v4l2.c
> index c847bcea6e95..6111d74f68c9 100644
> --- a/drivers/media/common/videobuf2/videobuf2-v4l2.c
> +++ b/drivers/media/common/videobuf2/videobuf2-v4l2.c
> @@ -724,7 +724,7 @@ int vb2_reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req)
> int ret = vb2_verify_memory_type(q, req->memory, req->type);
>
> fill_buf_caps(q, &req->capabilities);
> - return ret ? ret : vb2_core_reqbufs(q, req->memory, &req->count);
> + return ret ? ret : vb2_core_reqbufs(q, req->memory, true, &req->count);
> }
> EXPORT_SYMBOL_GPL(vb2_reqbufs);
>
> @@ -798,7 +798,7 @@ 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,
> + return ret ? ret : vb2_core_create_bufs(q, create->memory, true,
> &create->count, requested_planes, requested_sizes);
> }
> EXPORT_SYMBOL_GPL(vb2_create_bufs);
> @@ -974,7 +974,7 @@ int vb2_ioctl_reqbufs(struct file *file, void *priv,
> return res;
> if (vb2_queue_is_busy(vdev, file))
> return -EBUSY;
> - res = vb2_core_reqbufs(vdev->queue, p->memory, &p->count);
> + res = vb2_core_reqbufs(vdev->queue, p->memory, true, &p->count);
> /* If count == 0, then the owner has released all buffers and he
> is no longer owner of the queue. Otherwise we have a new owner. */
> if (res == 0)
> diff --git a/drivers/media/dvb-core/dvb_vb2.c b/drivers/media/dvb-core/dvb_vb2.c
> index 6974f1731529..e60063652164 100644
> --- a/drivers/media/dvb-core/dvb_vb2.c
> +++ b/drivers/media/dvb-core/dvb_vb2.c
> @@ -342,7 +342,7 @@ int dvb_vb2_reqbufs(struct dvb_vb2_ctx *ctx, struct dmx_requestbuffers *req)
>
> ctx->buf_siz = req->size;
> ctx->buf_cnt = req->count;
> - ret = vb2_core_reqbufs(&ctx->vb_q, VB2_MEMORY_MMAP, &req->count);
> + ret = vb2_core_reqbufs(&ctx->vb_q, VB2_MEMORY_MMAP, true, &req->count);
> if (ret) {
> ctx->state = DVB_VB2_STATE_NONE;
> dprintk(1, "[%s] count=%d size=%d errno=%d\n", ctx->name,
> diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
> index 731fd9fbd506..ba83ac754c21 100644
> --- a/include/media/videobuf2-core.h
> +++ b/include/media/videobuf2-core.h
> @@ -737,6 +737,7 @@ void vb2_core_querybuf(struct vb2_queue *q, unsigned int index, void *pb);
> * vb2_core_reqbufs() - Initiate streaming.
> * @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.
> *
> * Videobuf2 core helper to implement VIDIOC_REQBUF() operation. It is called
> @@ -761,12 +762,13 @@ void vb2_core_querybuf(struct vb2_queue *q, unsigned int index, void *pb);
> * Return: returns zero on success; an error code otherwise.
> */
> int vb2_core_reqbufs(struct vb2_queue *q, enum vb2_memory memory,
> - unsigned int *count);
> + bool consistent_mem, unsigned int *count);
>
> /**
> * 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.
> @@ -784,7 +786,8 @@ 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[]);
>
> /**
>

Next message: Veerabhadrarao Badiganti: "[PATCH V3 0/2] Deactivate CQE during SDHC reset"
Previous message: Dave Stevenson: "Re: [PATCH v2 2/3] media: i2c: imx219: Add support for RAW8 bit bayer format"
In reply to: Sergey Senozhatsky: "[PATCHv4 04/11] videobuf2: add queue memory consistency parameter"
Next in thread: Sergey Senozhatsky: "Re: [PATCHv4 04/11] videobuf2: add queue memory consistency parameter"
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