[PATCH v6] drm/syncobj: Extend EXPORT_SYNC_FILE for timeline syncobjs - Linaro-mm-sig

1 Apr 2025

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
v4: Also handle IMPORT_SYNC_FILE case
v5: Address comments from Dmitry
v6: checkpatch.pl nits
Signed-off-by: Rob Clark robdclark@chromium.org
Reviewed-by: Christian König christian.koenig@amd.com
Reviewed-by: Dmitry Osipenko dmitry.osipenko@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;
@@ -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


    