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

[Christian König]

Am 01.04.25 um 22:46 schrieb Dmitry Osipenko:
> On 4/1/25 23:40, Rob Clark wrote:
>> 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
> Christian already applied to misc-test, please rebase and make it as a
> new patch

Yeah, sorry I was a bit to quick obviously.

On the other hand I don't see an immediate need for a check for DRIVER_SYNCOBJ_TIMELINE here.

The functions should work even when the driver doesn't handle timeline syncobj on it's own.

Regards,
Christian.