drm/syncobj: extend syncobj query ability v3

user space needs a flexiable query ability.
So that umd can get last signaled or submitted point.
v2:
add sanitizer checking.
v3:
rebase

Change-Id: I6512b430524ebabe715e602a2bf5abb0a7e780ea
Signed-off-by: Chunming Zhou <[e-mail]>
Cc: Lionel Landwerlin <[e-mail]>
Cc: Christian König <[e-mail]>
Reviewed-by: Lionel Landwerlin <[e-mail]>
Signed-off-by: Christian König <[e-mail]>
Link: https://patchwork.freedesktop.org/series/64044/

drivers/gpu/drm/drm_syncobj.c

···
 	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ_TIMELINE))
 		return -EOPNOTSUPP;
 
-	if (args->pad != 0)
+	if (args->flags != 0)
 		return -EINVAL;
 
 	if (args->count_handles == 0)
···
 	if (!drm_core_check_feature(dev, DRIVER_SYNCOBJ_TIMELINE))
 		return -EOPNOTSUPP;
 
-	if (args->pad != 0)
+	if (args->flags & ~DRM_SYNCOBJ_QUERY_FLAGS_LAST_SUBMITTED)
 		return -EINVAL;
 
 	if (args->count_handles == 0)
···
 		fence = drm_syncobj_fence_get(syncobjs[i]);
 		chain = to_dma_fence_chain(fence);
 		if (chain) {
-			struct dma_fence *iter, *last_signaled = NULL;
+			struct dma_fence *iter, *last_signaled =
+				dma_fence_get(fence);
 
-			dma_fence_chain_for_each(iter, fence) {
-				if (iter->context != fence->context) {
-					dma_fence_put(iter);
-					/* It is most likely that timeline has
-					 * unorder points. */
-					break;
+			if (args->flags &
+			    DRM_SYNCOBJ_QUERY_FLAGS_LAST_SUBMITTED) {
+				point = fence->seqno;
+			} else {
+				dma_fence_chain_for_each(iter, fence) {
+					if (iter->context != fence->context) {
+						dma_fence_put(iter);
+						/* It is most likely that timeline has
+						* unorder points. */
+						break;
+					}
+					dma_fence_put(last_signaled);
+					last_signaled = dma_fence_get(iter);
 				}
-				dma_fence_put(last_signaled);
-				last_signaled = dma_fence_get(iter);
+				point = dma_fence_is_signaled(last_signaled) ?
+					last_signaled->seqno :
+					to_dma_fence_chain(last_signaled)->prev_seqno;
 			}
-			point = dma_fence_is_signaled(last_signaled) ?
-				last_signaled->seqno :
-				to_dma_fence_chain(last_signaled)->prev_seqno;
 			dma_fence_put(last_signaled);
 		} else {
 			point = 0;
 		}
+		dma_fence_put(fence);
 		ret = copy_to_user(&points[i], &point, sizeof(uint64_t));
 		ret = ret ? -EFAULT : 0;
 		if (ret)

include/uapi/drm/drm.h

···
 	__u32 pad;
 };
 
+#define DRM_SYNCOBJ_QUERY_FLAGS_LAST_SUBMITTED (1 << 0) /* last available point on timeline syncobj */
 struct drm_syncobj_timeline_array {
 	__u64 handles;
 	__u64 points;
 	__u32 count_handles;
-	__u32 pad;
+	__u32 flags;
 };