[PATCH v3] drm/syncobj: Extend EXPORT_SYNC_FILE for timeline syncobjs

[Rob Clark <robdclark@gmail.com>]

From: Rob Clark <robdclark@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

Signed-off-by: Rob Clark <robdclark@chromium.org>
---
 drivers/gpu/drm/drm_syncobj.c | 18 +++++++++++++-----
 include/uapi/drm/drm.h        |  3 +++
 2 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/drm_syncobj.c b/drivers/gpu/drm/drm_syncobj.c
index 4f2ab8a7b50f..bc57d6f1a22e 100644
--- a/drivers/gpu/drm/drm_syncobj.c
+++ b/drivers/gpu/drm/drm_syncobj.c
@@ -762,7 +762,7 @@ static int drm_syncobj_import_sync_file_fence(struct drm_file *file_private,
 }
 
 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 +772,7 @@ 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 +869,9 @@ drm_syncobj_handle_to_fd_ioctl(struct drm_device *dev, void *data,
 				   struct drm_file *file_private)
 {
 	struct drm_syncobj_handle *args = data;
+	unsigned 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 +879,18 @@ 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 != 0 && (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);
diff --git a/include/uapi/drm/drm.h b/include/uapi/drm/drm.h
index 7fba37b94401..dd0fd13eadbd 100644
--- a/include/uapi/drm/drm.h
+++ b/include/uapi/drm/drm.h
@@ -906,12 +906,15 @@ struct drm_syncobj_destroy {
 
 #define DRM_SYNCOBJ_FD_TO_HANDLE_FLAGS_IMPORT_SYNC_FILE (1 << 0)
 #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