On 02/08/2025 11:22, Jacopo Mondi wrote:
> From: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
> 
> Accessing file->private_data manually to retrieve the v4l2_fh pointer is
> error-prone, as the field is a void * and will happily cast implicitly
> to any pointer type.
> 
> Replace all remaining locations that read the v4l2_fh pointer directly
> from file->private_data and cast it to driver-specific file handle
> structures with driver-specific functions that use file_to_v4l2_fh() and
> perform the same cast.
> 
> No functional change is intended, this only paves the way to remove
> direct accesses to file->private_data and make V4L2 drivers safer.
> Other accesses to the field will be addressed separately.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
> Signed-off-by: Jacopo Mondi <jacopo.mo...@ideasonboard.com>
> ---
>  drivers/media/pci/ivtv/ivtv-driver.h               |  5 ++++
>  drivers/media/pci/ivtv/ivtv-fileops.c              | 10 +++----
>  drivers/media/pci/ivtv/ivtv-ioctl.c                |  8 +++---
>  drivers/media/platform/allegro-dvt/allegro-core.c  |  7 ++++-
>  drivers/media/platform/amlogic/meson-ge2d/ge2d.c   |  8 ++++--
>  .../media/platform/chips-media/coda/coda-common.c  |  7 ++++-
>  .../platform/chips-media/wave5/wave5-helper.c      |  2 +-
>  .../media/platform/chips-media/wave5/wave5-vpu.h   |  5 ++++
>  drivers/media/platform/m2m-deinterlace.c           |  7 ++++-
>  .../media/platform/mediatek/jpeg/mtk_jpeg_core.c   |  7 ++++-
>  drivers/media/platform/mediatek/mdp/mtk_mdp_m2m.c  |  7 ++++-
>  .../media/platform/mediatek/mdp3/mtk-mdp3-m2m.c    |  7 ++++-
>  .../mediatek/vcodec/decoder/mtk_vcodec_dec_drv.c   |  2 +-
>  .../mediatek/vcodec/decoder/mtk_vcodec_dec_drv.h   |  5 ++++
>  .../mediatek/vcodec/encoder/mtk_vcodec_enc_drv.c   |  2 +-
>  .../mediatek/vcodec/encoder/mtk_vcodec_enc_drv.h   |  5 ++++
>  drivers/media/platform/nxp/imx-jpeg/mxc-jpeg.c     |  7 ++++-
>  drivers/media/platform/nxp/imx8-isi/imx8-isi-m2m.c |  7 ++++-
>  drivers/media/platform/nxp/mx2_emmaprp.c           |  7 ++++-
>  drivers/media/platform/renesas/rcar_fdp1.c         |  7 ++++-
>  drivers/media/platform/renesas/rcar_jpu.c          |  7 ++++-
>  drivers/media/platform/rockchip/rga/rga.c          |  3 +--
>  drivers/media/platform/rockchip/rga/rga.h          |  5 ++++
>  drivers/media/platform/rockchip/rkvdec/rkvdec.c    |  2 +-
>  drivers/media/platform/rockchip/rkvdec/rkvdec.h    |  5 ++++
>  .../media/platform/samsung/exynos-gsc/gsc-core.h   |  6 +++++
>  .../media/platform/samsung/exynos-gsc/gsc-m2m.c    |  6 ++---
>  .../media/platform/samsung/exynos4-is/fimc-core.h  |  5 ++++
>  .../media/platform/samsung/exynos4-is/fimc-m2m.c   |  2 +-
>  drivers/media/platform/samsung/s5p-g2d/g2d.c       |  7 +++--
>  .../media/platform/samsung/s5p-jpeg/jpeg-core.c    |  9 +++++--
>  drivers/media/platform/samsung/s5p-mfc/s5p_mfc.c   |  6 ++---
>  .../platform/samsung/s5p-mfc/s5p_mfc_common.h      |  6 +++++
>  drivers/media/platform/st/sti/bdisp/bdisp-v4l2.c   |  7 ++++-
>  drivers/media/platform/st/sti/delta/delta-v4l2.c   | 26 +++++++++++-------
>  drivers/media/platform/st/sti/hva/hva-v4l2.c       | 31 
> ++++++++++++----------
>  drivers/media/platform/st/sti/hva/hva.h            |  2 --
>  drivers/media/platform/st/stm32/dma2d/dma2d.c      |  7 +++--
>  drivers/media/platform/sunxi/sun8i-di/sun8i-di.c   |  3 +--
>  .../platform/sunxi/sun8i-rotate/sun8i_rotate.c     |  3 +--
>  drivers/media/platform/ti/omap3isp/ispvideo.c      |  4 +--
>  drivers/media/platform/ti/omap3isp/ispvideo.h      |  6 +++++
>  drivers/media/platform/verisilicon/hantro.h        |  5 ++++
>  drivers/media/platform/verisilicon/hantro_drv.c    |  3 +--
>  drivers/staging/media/imx/imx-media-csc-scaler.c   |  7 ++++-
>  drivers/staging/media/meson/vdec/vdec.c            | 24 ++++++-----------
>  drivers/staging/media/meson/vdec/vdec.h            |  5 ++++
>  drivers/staging/media/sunxi/cedrus/cedrus.c        |  3 +--
>  drivers/staging/media/sunxi/cedrus/cedrus.h        |  5 ++++
>  drivers/staging/media/sunxi/cedrus/cedrus_video.c  |  5 ----
>  50 files changed, 237 insertions(+), 100 deletions(-)
> 
> diff --git a/drivers/media/pci/ivtv/ivtv-driver.h 
> b/drivers/media/pci/ivtv/ivtv-driver.h
> index 
> a6ffa99e16bc64a5b7d3e48c1ab32b49a7989242..cad548b28e360ecfe2bcb9fcb5d12cd8823c3727
>  100644
> --- a/drivers/media/pci/ivtv/ivtv-driver.h
> +++ b/drivers/media/pci/ivtv/ivtv-driver.h
> @@ -388,6 +388,11 @@ static inline struct ivtv_open_id *fh2id(struct v4l2_fh 
> *fh)
>       return container_of(fh, struct ivtv_open_id, fh);
>  }
>  
> +static inline struct ivtv_open_id *file2id(struct file *filp)
> +{
> +     return container_of(file_to_v4l2_fh(filp), struct ivtv_open_id, fh);

Why not write:

        return fh2id(file_to_v4l2_fh(filp));

Same for all other drivers that do this. I prefer to have the contained_of()
in just one place.

> +}
> +
>  struct yuv_frame_info
>  {
>       u32 update;

<snip>

> diff --git a/drivers/media/platform/allegro-dvt/allegro-core.c 
> b/drivers/media/platform/allegro-dvt/allegro-core.c
> index 
> 1f134e08923a528cc676f825da68951c97ac2f25..74977f3ae4844022c04de877f31b4fc6aaac0749
>  100644
> --- a/drivers/media/platform/allegro-dvt/allegro-core.c
> +++ b/drivers/media/platform/allegro-dvt/allegro-core.c
> @@ -302,6 +302,11 @@ struct allegro_channel {
>       unsigned int error;
>  };
>  
> +static inline struct allegro_channel *file_to_channel(struct file *filp)
> +{
> +     return container_of(file_to_v4l2_fh(filp), struct allegro_channel, fh);
> +}
> +
>  static inline int
>  allegro_channel_get_i_frame_qp(struct allegro_channel *channel)
>  {
> @@ -3229,7 +3234,7 @@ static int allegro_open(struct file *file)
>  
>  static int allegro_release(struct file *file)
>  {
> -     struct allegro_channel *channel = fh_to_channel(file->private_data);
> +     struct allegro_channel *channel = file_to_channel(file);

So a file_to_channel inline function was added, but it is used in just one
place.

I would prefer to just drop the inline function and instead write:

        struct allegro_channel *channel = fh_to_channel(file_to_v4l2_fh(file));

If this is needed in two or more places, then the extra inline makes sense,
but it is a fairly common pattern that it is only needed in the release 
function.

Adding a new inline just for that seems overkill to me.

>  
>       v4l2_m2m_ctx_release(channel->fh.m2m_ctx);
>  

Regards,

        Hans


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