Re: Re: [PATCH] media: cedrus: Don't kernel map most buffers

From: Jernej Škrabec
Date: Mon Oct 04 2021 - 12:06:33 EST

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In reply to: Hans Verkuil: "Re: [PATCH] media: cedrus: Don't kernel map most buffers"
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Hi!

Dne ponedeljek, 04. oktober 2021 ob 10:10:55 CEST je Hans Verkuil napisal(a):
> Hi Jernej,
>
> Some comments below:
>
> On 12/09/2021 08:08, Jernej Skrabec wrote:
> > Except VP8 probability coefficients buffer, all other buffers are never
>
> Except -> Except for
>

Ok.

> > accessed by CPU. That allows us to mark them with
DMA_ATTR_NO_KERNEL_MAPPING
> > flag. This helps with decoding big (like 4k) videos on 32-bit ARM
> > platforms where default vmalloc size is relatively small - 240 MiB.
> > Since auxiliary buffer are not yet efficiently allocated, this can be
> > easily exceeded. Even if allocation is optimized, 4k videos will still
> > often exceed this limit.
> >
> > Signed-off-by: Jernej Skrabec <jernej.skrabec@xxxxxxxxx>
> > ---
> > .../staging/media/sunxi/cedrus/cedrus_h264.c | 102 ++++++++++--------
> > .../staging/media/sunxi/cedrus/cedrus_h265.c | 28 ++---
> > .../staging/media/sunxi/cedrus/cedrus_video.c | 2 +
> > 3 files changed, 73 insertions(+), 59 deletions(-)
> >
> > diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_h264.c b/drivers/
staging/media/sunxi/cedrus/cedrus_h264.c
> > index de7442d4834d..6e38b37d9fe1 100644
> > --- a/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
> > +++ b/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
> > @@ -538,23 +538,23 @@ static int cedrus_h264_start(struct cedrus_ctx *ctx)
> >
> > ctx->codec.h264.pic_info_buf_size = pic_info_size;
> > ctx->codec.h264.pic_info_buf =
> > - dma_alloc_coherent(dev->dev, ctx-
>codec.h264.pic_info_buf_size,
> > - &ctx-
>codec.h264.pic_info_buf_dma,
> > - GFP_KERNEL);
> > + dma_alloc_attrs(dev->dev, ctx-
>codec.h264.pic_info_buf_size,
> > + &ctx-
>codec.h264.pic_info_buf_dma,
> > + GFP_KERNEL,
DMA_ATTR_NO_KERNEL_MAPPING);
> > if (!ctx->codec.h264.pic_info_buf)
> > return -ENOMEM;
> >
> > /*
> > * That buffer is supposed to be 16kiB in size, and be aligned
> > - * on 16kiB as well. However, dma_alloc_coherent provides the
> > + * on 16kiB as well. However, dma_alloc_attrs provides the
> > * guarantee that we'll have a CPU and DMA address aligned on
>
> Does the 'CPU' part of this sentence still make sense since the CPU
> won't access the buffer?
>

Good catch! I'll remove it.

> > * the smallest page order that is greater to the requested
> > * size, so we don't have to overallocate.
> > */
> > ctx->codec.h264.neighbor_info_buf =
> > - dma_alloc_coherent(dev->dev,
CEDRUS_NEIGHBOR_INFO_BUF_SIZE,
> > - &ctx-
>codec.h264.neighbor_info_buf_dma,
> > - GFP_KERNEL);
> > + dma_alloc_attrs(dev->dev,
CEDRUS_NEIGHBOR_INFO_BUF_SIZE,
> > + &ctx-
>codec.h264.neighbor_info_buf_dma,
> > + GFP_KERNEL,
DMA_ATTR_NO_KERNEL_MAPPING);
>
> I think it would be good to have a comment for all these dma_alloc_attrs
> calls where you note that these buffers are used by the HW only, and
> never by the CPU, hence the use of DMA_ATTR_NO_KERNEL_MAPPING.
>

Ok.

> > if (!ctx->codec.h264.neighbor_info_buf) {
> > ret = -ENOMEM;
> > goto err_pic_buf;
> > @@ -582,10 +582,11 @@ static int cedrus_h264_start(struct cedrus_ctx *ctx)
> >
> > mv_col_size = field_size * 2 * CEDRUS_H264_FRAME_NUM;
> > ctx->codec.h264.mv_col_buf_size = mv_col_size;
> > - ctx->codec.h264.mv_col_buf = dma_alloc_coherent(dev->dev,
> > -
ctx->codec.h264.mv_col_buf_size,
> > -
&ctx->codec.h264.mv_col_buf_dma,
> > -
GFP_KERNEL);
> > + ctx->codec.h264.mv_col_buf =
> > + dma_alloc_attrs(dev->dev,
> > + ctx->codec.h264.mv_col_buf_size,
> > + &ctx->codec.h264.mv_col_buf_dma,
> > + GFP_KERNEL,
DMA_ATTR_NO_KERNEL_MAPPING);
> > if (!ctx->codec.h264.mv_col_buf) {
> > ret = -ENOMEM;
> > goto err_neighbor_buf;
> > @@ -600,10 +601,10 @@ static int cedrus_h264_start(struct cedrus_ctx *ctx)
> > ctx->codec.h264.deblk_buf_size =
> > ALIGN(ctx->src_fmt.width, 32) * 12;
> > ctx->codec.h264.deblk_buf =
> > - dma_alloc_coherent(dev->dev,
> > - ctx-
>codec.h264.deblk_buf_size,
> > - &ctx-
>codec.h264.deblk_buf_dma,
> > - GFP_KERNEL);
> > + dma_alloc_attrs(dev->dev,
> > + ctx-
>codec.h264.deblk_buf_size,
> > + &ctx-
>codec.h264.deblk_buf_dma,
> > + GFP_KERNEL,
DMA_ATTR_NO_KERNEL_MAPPING);
> > if (!ctx->codec.h264.deblk_buf) {
> > ret = -ENOMEM;
> > goto err_mv_col_buf;
> > @@ -616,10 +617,10 @@ static int cedrus_h264_start(struct cedrus_ctx *ctx)
> > ctx->codec.h264.intra_pred_buf_size =
> > ALIGN(ctx->src_fmt.width, 64) * 5 * 2;
> > ctx->codec.h264.intra_pred_buf =
> > - dma_alloc_coherent(dev->dev,
> > - ctx-
>codec.h264.intra_pred_buf_size,
> > - &ctx-
>codec.h264.intra_pred_buf_dma,
> > - GFP_KERNEL);
> > + dma_alloc_attrs(dev->dev,
> > + ctx-
>codec.h264.intra_pred_buf_size,
> > + &ctx-
>codec.h264.intra_pred_buf_dma,
> > + GFP_KERNEL,
DMA_ATTR_NO_KERNEL_MAPPING);
> > if (!ctx->codec.h264.intra_pred_buf) {
> > ret = -ENOMEM;
> > goto err_deblk_buf;
> > @@ -629,24 +630,28 @@ static int cedrus_h264_start(struct cedrus_ctx *ctx)
> > return 0;
> >
> > err_deblk_buf:
> > - dma_free_coherent(dev->dev, ctx->codec.h264.deblk_buf_size,
> > - ctx->codec.h264.deblk_buf,
> > - ctx->codec.h264.deblk_buf_dma);
> > + dma_free_attrs(dev->dev, ctx->codec.h264.deblk_buf_size,
> > + ctx->codec.h264.deblk_buf,
> > + ctx->codec.h264.deblk_buf_dma,
> > + DMA_ATTR_NO_KERNEL_MAPPING);
> >
> > err_mv_col_buf:
> > - dma_free_coherent(dev->dev, ctx->codec.h264.mv_col_buf_size,
> > - ctx->codec.h264.mv_col_buf,
> > - ctx->codec.h264.mv_col_buf_dma);
> > + dma_free_attrs(dev->dev, ctx->codec.h264.mv_col_buf_size,
> > + ctx->codec.h264.mv_col_buf,
> > + ctx->codec.h264.mv_col_buf_dma,
> > + DMA_ATTR_NO_KERNEL_MAPPING);
> >
> > err_neighbor_buf:
> > - dma_free_coherent(dev->dev, CEDRUS_NEIGHBOR_INFO_BUF_SIZE,
> > - ctx->codec.h264.neighbor_info_buf,
> > - ctx->codec.h264.neighbor_info_buf_dma);
> > + dma_free_attrs(dev->dev, CEDRUS_NEIGHBOR_INFO_BUF_SIZE,
> > + ctx->codec.h264.neighbor_info_buf,
> > + ctx->codec.h264.neighbor_info_buf_dma,
> > + DMA_ATTR_NO_KERNEL_MAPPING);
> >
> > err_pic_buf:
> > - dma_free_coherent(dev->dev, ctx->codec.h264.pic_info_buf_size,
> > - ctx->codec.h264.pic_info_buf,
> > - ctx->codec.h264.pic_info_buf_dma);
> > + dma_free_attrs(dev->dev, ctx->codec.h264.pic_info_buf_size,
> > + ctx->codec.h264.pic_info_buf,
> > + ctx->codec.h264.pic_info_buf_dma,
> > + DMA_ATTR_NO_KERNEL_MAPPING);
> > return ret;
> > }
> >
> > @@ -654,23 +659,28 @@ static void cedrus_h264_stop(struct cedrus_ctx *ctx)
> > {
> > struct cedrus_dev *dev = ctx->dev;
> >
> > - dma_free_coherent(dev->dev, ctx->codec.h264.mv_col_buf_size,
> > - ctx->codec.h264.mv_col_buf,
> > - ctx->codec.h264.mv_col_buf_dma);
> > - dma_free_coherent(dev->dev, CEDRUS_NEIGHBOR_INFO_BUF_SIZE,
> > - ctx->codec.h264.neighbor_info_buf,
> > - ctx->codec.h264.neighbor_info_buf_dma);
> > - dma_free_coherent(dev->dev, ctx->codec.h264.pic_info_buf_size,
> > - ctx->codec.h264.pic_info_buf,
> > - ctx->codec.h264.pic_info_buf_dma);
> > + dma_free_attrs(dev->dev, ctx->codec.h264.mv_col_buf_size,
> > + ctx->codec.h264.mv_col_buf,
> > + ctx->codec.h264.mv_col_buf_dma,
> > + DMA_ATTR_NO_KERNEL_MAPPING);
> > + dma_free_attrs(dev->dev, CEDRUS_NEIGHBOR_INFO_BUF_SIZE,
> > + ctx->codec.h264.neighbor_info_buf,
> > + ctx->codec.h264.neighbor_info_buf_dma,
> > + DMA_ATTR_NO_KERNEL_MAPPING);
> > + dma_free_attrs(dev->dev, ctx->codec.h264.pic_info_buf_size,
> > + ctx->codec.h264.pic_info_buf,
> > + ctx->codec.h264.pic_info_buf_dma,
> > + DMA_ATTR_NO_KERNEL_MAPPING);
> > if (ctx->codec.h264.deblk_buf_size)
> > - dma_free_coherent(dev->dev, ctx-
>codec.h264.deblk_buf_size,
> > - ctx->codec.h264.deblk_buf,
> > - ctx->codec.h264.deblk_buf_dma);
> > + dma_free_attrs(dev->dev, ctx-
>codec.h264.deblk_buf_size,
> > + ctx->codec.h264.deblk_buf,
> > + ctx->codec.h264.deblk_buf_dma,
> > + DMA_ATTR_NO_KERNEL_MAPPING);
> > if (ctx->codec.h264.intra_pred_buf_size)
> > - dma_free_coherent(dev->dev, ctx-
>codec.h264.intra_pred_buf_size,
> > - ctx->codec.h264.intra_pred_buf,
> > - ctx-
>codec.h264.intra_pred_buf_dma);
> > + dma_free_attrs(dev->dev, ctx-
>codec.h264.intra_pred_buf_size,
> > + ctx->codec.h264.intra_pred_buf,
> > + ctx->codec.h264.intra_pred_buf_dma,
> > + DMA_ATTR_NO_KERNEL_MAPPING);
> > }
> >
> > static void cedrus_h264_trigger(struct cedrus_ctx *ctx)
> > diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_h265.c b/drivers/
staging/media/sunxi/cedrus/cedrus_h265.c
> > index 3d9561d4aadb..bb7eb56106c5 100644
> > --- a/drivers/staging/media/sunxi/cedrus/cedrus_h265.c
> > +++ b/drivers/staging/media/sunxi/cedrus/cedrus_h265.c
> > @@ -351,10 +351,10 @@ static void cedrus_h265_setup(struct cedrus_ctx
*ctx,
> > ctx->codec.h265.mv_col_buf_unit_size;
> >
> > ctx->codec.h265.mv_col_buf =
> > - dma_alloc_coherent(dev->dev,
> > - ctx-
>codec.h265.mv_col_buf_size,
> > - &ctx-
>codec.h265.mv_col_buf_addr,
> > - GFP_KERNEL);
> > + dma_alloc_attrs(dev->dev,
> > + ctx-
>codec.h265.mv_col_buf_size,
> > + &ctx-
>codec.h265.mv_col_buf_addr,
> > + GFP_KERNEL,
DMA_ATTR_NO_KERNEL_MAPPING);
> > if (!ctx->codec.h265.mv_col_buf) {
> > ctx->codec.h265.mv_col_buf_size = 0;
> > // TODO: Abort the process here.
> > @@ -668,9 +668,9 @@ static int cedrus_h265_start(struct cedrus_ctx *ctx)
> > ctx->codec.h265.mv_col_buf_size = 0;
> >
> > ctx->codec.h265.neighbor_info_buf =
> > - dma_alloc_coherent(dev->dev,
CEDRUS_H265_NEIGHBOR_INFO_BUF_SIZE,
> > - &ctx-
>codec.h265.neighbor_info_buf_addr,
> > - GFP_KERNEL);
> > + dma_alloc_attrs(dev->dev,
CEDRUS_H265_NEIGHBOR_INFO_BUF_SIZE,
> > + &ctx-
>codec.h265.neighbor_info_buf_addr,
> > + GFP_KERNEL,
DMA_ATTR_NO_KERNEL_MAPPING);
> > if (!ctx->codec.h265.neighbor_info_buf)
> > return -ENOMEM;
> >
> > @@ -682,16 +682,18 @@ static void cedrus_h265_stop(struct cedrus_ctx *ctx)
> > struct cedrus_dev *dev = ctx->dev;
> >
> > if (ctx->codec.h265.mv_col_buf_size > 0) {
> > - dma_free_coherent(dev->dev, ctx-
>codec.h265.mv_col_buf_size,
> > - ctx->codec.h265.mv_col_buf,
> > - ctx-
>codec.h265.mv_col_buf_addr);
> > + dma_free_attrs(dev->dev, ctx-
>codec.h265.mv_col_buf_size,
> > + ctx->codec.h265.mv_col_buf,
> > + ctx->codec.h265.mv_col_buf_addr,
> > + DMA_ATTR_NO_KERNEL_MAPPING);
> >
> > ctx->codec.h265.mv_col_buf_size = 0;
> > }
> >
> > - dma_free_coherent(dev->dev, CEDRUS_H265_NEIGHBOR_INFO_BUF_SIZE,
> > - ctx->codec.h265.neighbor_info_buf,
> > - ctx->codec.h265.neighbor_info_buf_addr);
> > + dma_free_attrs(dev->dev, CEDRUS_H265_NEIGHBOR_INFO_BUF_SIZE,
> > + ctx->codec.h265.neighbor_info_buf,
> > + ctx->codec.h265.neighbor_info_buf_addr,
> > + DMA_ATTR_NO_KERNEL_MAPPING);
> > }
> >
> > static void cedrus_h265_trigger(struct cedrus_ctx *ctx)
> > diff --git a/drivers/staging/media/sunxi/cedrus/cedrus_video.c b/drivers/
staging/media/sunxi/cedrus/cedrus_video.c
> > index 66714609b577..800ffa5382de 100644
> > --- a/drivers/staging/media/sunxi/cedrus/cedrus_video.c
> > +++ b/drivers/staging/media/sunxi/cedrus/cedrus_video.c
> > @@ -568,6 +568,7 @@ int cedrus_queue_init(void *priv, struct vb2_queue
*src_vq,
> >
> > src_vq->type = V4L2_BUF_TYPE_VIDEO_OUTPUT;
> > src_vq->io_modes = VB2_MMAP | VB2_DMABUF;
> > + src_vq->dma_attrs = DMA_ATTR_NO_KERNEL_MAPPING;
> > src_vq->drv_priv = ctx;
> > src_vq->buf_struct_size = sizeof(struct cedrus_buffer);
> > src_vq->ops = &cedrus_qops;
> > @@ -584,6 +585,7 @@ int cedrus_queue_init(void *priv, struct vb2_queue
*src_vq,
> >
> > dst_vq->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
> > dst_vq->io_modes = VB2_MMAP | VB2_DMABUF;
> > + src_vq->dma_attrs = DMA_ATTR_NO_KERNEL_MAPPING;
>
> This should be dst_vq!
>
> I'm also not quite sure that it is right to use this for the destination
> buffer. Could this cause problems if this buffer is exported to a dmabuf
> and another driver will be using it and requiring a kernel mapping.

Hm, if I fix this, it actually breaks DRM mapping. For some reason it expects
vmap to be valid. I'll drop this for now.

Thanks for review!

Best regards,
Jernej

>
> Regards,
>
> Hans
>
> > dst_vq->drv_priv = ctx;
> > dst_vq->buf_struct_size = sizeof(struct cedrus_buffer);
> > dst_vq->ops = &cedrus_qops;
> >
>
>

Next message: Ido Schimmel: "Re: [PATCH v6 07/11] PCI: Replace pci_dev::driver usage that gets the driver name"
Previous message: Haakon Bugge: "Re: [syzbot] BUG: RESTRACK detected leak of resources"
In reply to: Hans Verkuil: "Re: [PATCH] media: cedrus: Don't kernel map most buffers"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]