[PATCH v6] drm/syncobj: Extend EXPORT_SYNC_FILE for timeline syncobjs

Rob Clark robdclark at gmail.com
Tue Apr 1 20:40:49 UTC 2025


On Tue, Apr 1, 2025 at 8:58 AM Rob Clark <robdclark at gmail.com> wrote:
>
> From: Rob Clark <robdclark at chromium.org>
>
> Add support for exporting a dma_fence fd for a specific point on a
> timeline.  This is needed for vtest/vpipe[1][2] to implement timeline
> syncobj support, as it needs a way to turn a point on a timeline back
> into a dma_fence fd.  It also closes an odd omission from the syncobj
> UAPI.
>
> [1] https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33433
> [2] https://gitlab.freedesktop.org/virgl/virglrenderer/-/merge_requests/805
>
> v2: Add DRM_SYNCOBJ_HANDLE_TO_FD_FLAGS_TIMELINE
> v3: Add unstaged uabi header hunk
> v4: Also handle IMPORT_SYNC_FILE case
> v5: Address comments from Dmitry
> v6: checkpatch.pl nits
>
> Signed-off-by: Rob Clark <robdclark at chromium.org>
> Reviewed-by: Christian König <christian.koenig at amd.com>
> Reviewed-by: Dmitry Osipenko <dmitry.osipenko at collabora.com>
> ---
>  drivers/gpu/drm/drm_syncobj.c | 47 +++++++++++++++++++++++++++--------
>  include/uapi/drm/drm.h        |  4 +++
>  2 files changed, 41 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
> index 4f2ab8a7b50f..636cd83ca29e 100644
> --- a/drivers/gpu/drm/drm_syncobj.c
> +++ b/drivers/gpu/drm/drm_syncobj.c
> @@ -741,7 +741,7 @@ static int drm_syncobj_fd_to_handle(struct drm_file *file_private,
>  }
>
>  static int drm_syncobj_import_sync_file_fence(struct drm_file *file_private,
> -                                             int fd, int handle)
> +                                             int fd, int handle, u64 point)
>  {
>         struct dma_fence *fence = sync_file_get_fence(fd);
>         struct drm_syncobj *syncobj;
> @@ -755,14 +755,24 @@ static int drm_syncobj_import_sync_file_fence(struct drm_file *file_private,
>                 return -ENOENT;
>         }
>
> -       drm_syncobj_replace_fence(syncobj, fence);
> +       if (point) {
> +               struct dma_fence_chain *chain = dma_fence_chain_alloc();
> +
> +               if (!chain)
> +                       return -ENOMEM;
> +
> +               drm_syncobj_add_point(syncobj, chain, fence, point);
> +       } else {
> +               drm_syncobj_replace_fence(syncobj, fence);
> +       }
> +
>         dma_fence_put(fence);
>         drm_syncobj_put(syncobj);
>         return 0;
>  }
>
>  static int drm_syncobj_export_sync_file(struct drm_file *file_private,
> -                                       int handle, int *p_fd)
> +                                       int handle, u64 point, int *p_fd)
>  {
>         int ret;
>         struct dma_fence *fence;
> @@ -772,7 +782,7 @@ static int drm_syncobj_export_sync_file(struct drm_file *file_private,
>         if (fd < 0)
>                 return fd;
>
> -       ret = drm_syncobj_find_fence(file_private, handle, 0, 0, &fence);
> +       ret = drm_syncobj_find_fence(file_private, handle, point, 0, &fence);
>         if (ret)
>                 goto err_put_fd;
>
> @@ -869,6 +879,9 @@ drm_syncobj_handle_to_fd_ioctl(struct drm_device *dev, void *data,
>                                    struct drm_file *file_private)
>  {
>         struct drm_syncobj_handle *args = data;
> +       unsigned int valid_flags = DRM_SYNCOBJ_HANDLE_TO_FD_FLAGS_TIMELINE |
> +                                  DRM_SYNCOBJ_HANDLE_TO_FD_FLAGS_EXPORT_SYNC_FILE;
> +       u64 point = 0;
>
>         if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ))
>                 return -EOPNOTSUPP;
> @@ -876,13 +889,18 @@ drm_syncobj_handle_to_fd_ioctl(struct drm_device *dev, void *data,
>         if (args->pad)
>                 return -EINVAL;
>
> -       if (args->flags != 0 &&
> -           args->flags != DRM_SYNCOBJ_HANDLE_TO_FD_FLAGS_EXPORT_SYNC_FILE)
> +       if (args->flags & ~valid_flags)
>                 return -EINVAL;
>
> +       if (args->flags & DRM_SYNCOBJ_HANDLE_TO_FD_FLAGS_TIMELINE)
> +               point = args->point;
> +
>         if (args->flags & DRM_SYNCOBJ_HANDLE_TO_FD_FLAGS_EXPORT_SYNC_FILE)
>                 return drm_syncobj_export_sync_file(file_private, args->handle,
> -                                                   &args->fd);
> +                                                   point, &args->fd);
> +
> +       if (args->point)
> +               return -EINVAL;
>
>         return drm_syncobj_handle_to_fd(file_private, args->handle,
>                                         &args->fd);
> @@ -893,6 +911,9 @@ drm_syncobj_fd_to_handle_ioctl(struct drm_device *dev, void *data,
>                                    struct drm_file *file_private)
>  {
>         struct drm_syncobj_handle *args = data;
> +       unsigned int valid_flags = DRM_SYNCOBJ_FD_TO_HANDLE_FLAGS_TIMELINE |
> +                                  DRM_SYNCOBJ_FD_TO_HANDLE_FLAGS_IMPORT_SYNC_FILE;
> +       u64 point = 0;
>
>         if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ))
>                 return -EOPNOTSUPP;

oh, I suppose I should add a check for DRIVER_SYNCOBJ_TIMELINE?  I'll
send a v7 a bit later

BR,
-R

> @@ -900,14 +921,20 @@ drm_syncobj_fd_to_handle_ioctl(struct drm_device *dev, void *data,
>         if (args->pad)
>                 return -EINVAL;
>
> -       if (args->flags != 0 &&
> -           args->flags != DRM_SYNCOBJ_FD_TO_HANDLE_FLAGS_IMPORT_SYNC_FILE)
> +       if (args->flags & ~valid_flags)
>                 return -EINVAL;
>
> +       if (args->flags & DRM_SYNCOBJ_FD_TO_HANDLE_FLAGS_TIMELINE)
> +               point = args->point;
> +
>         if (args->flags & DRM_SYNCOBJ_FD_TO_HANDLE_FLAGS_IMPORT_SYNC_FILE)
>                 return drm_syncobj_import_sync_file_fence(file_private,
>                                                           args->fd,
> -                                                         args->handle);
> +                                                         args->handle,
> +                                                         point);
> +
> +       if (args->point)
> +               return -EINVAL;
>
>         return drm_syncobj_fd_to_handle(file_private, args->fd,
>                                         &args->handle);
> diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
> index 7fba37b94401..e63a71d3c607 100644
> --- a/include/uapi/drm/drm.h
> +++ b/include/uapi/drm/drm.h
> @@ -905,13 +905,17 @@ struct drm_syncobj_destroy {
>  };
>
>  #define DRM_SYNCOBJ_FD_TO_HANDLE_FLAGS_IMPORT_SYNC_FILE (1 << 0)
> +#define DRM_SYNCOBJ_FD_TO_HANDLE_FLAGS_TIMELINE         (1 << 1)
>  #define DRM_SYNCOBJ_HANDLE_TO_FD_FLAGS_EXPORT_SYNC_FILE (1 << 0)
> +#define DRM_SYNCOBJ_HANDLE_TO_FD_FLAGS_TIMELINE         (1 << 1)
>  struct drm_syncobj_handle {
>         __u32 handle;
>         __u32 flags;
>
>         __s32 fd;
>         __u32 pad;
> +
> +       __u64 point;
>  };
>
>  struct drm_syncobj_transfer {
> --
> 2.49.0
>


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