--- linux-4.9.37/drivers/dma-buf/sync_file.c	2017-07-12 16:42:41.000000000 +0300
+++ linux-4.9.y/drivers/dma-buf/sync_file.c	2021-06-07 13:01:33.000000000 +0300
@@ -67,9 +67,10 @@
  * sync_file_create() - creates a sync file
  * @fence:	fence to add to the sync_fence
  *
- * Creates a sync_file containg @fence. Once this is called, the sync_file
- * takes ownership of @fence. The sync_file can be released with
- * fput(sync_file->file). Returns the sync_file or NULL in case of error.
+ * Creates a sync_file containg @fence. This function acquires and additional
+ * reference of @fence for the newly-created &sync_file, if it succeeds. The
+ * sync_file can be released with fput(sync_file->file). Returns the
+ * sync_file or NULL in case of error.
  */
 struct sync_file *sync_file_create(struct fence *fence)
 {
@@ -79,7 +80,7 @@
 	if (!sync_file)
 		return NULL;
 
-	sync_file->fence = fence;
+	sync_file->fence = fence_get(fence);
 
 	snprintf(sync_file->name, sizeof(sync_file->name), "%s-%s%llu-%d",
 		 fence->ops->get_driver_name(fence),
@@ -90,14 +91,7 @@
 }
 EXPORT_SYMBOL(sync_file_create);
 
-/**
- * sync_file_fdget() - get a sync_file from an fd
- * @fd:		fd referencing a fence
- *
- * Ensures @fd references a valid sync_file, increments the refcount of the
- * backing file. Returns the sync_file or NULL in case of error.
- */
-static struct sync_file *sync_file_fdget(int fd)
+struct sync_file *sync_file_fdget(int fd)
 {
 	struct file *file = fget(fd);
 
@@ -114,6 +108,8 @@
 	return NULL;
 }
 
+EXPORT_SYMBOL(sync_file_fdget);
+
 /**
  * sync_file_get_fence - get the fence related to the sync_file fd
  * @fd:		sync_file fd to get the fence from
@@ -305,10 +301,9 @@
 
 	poll_wait(file, &sync_file->wq, wait);
 
-	if (!poll_does_not_wait(wait) &&
-	    !test_and_set_bit(POLL_ENABLED, &sync_file->fence->flags)) {
+	if (!test_and_set_bit(POLL_ENABLED, &sync_file->fence->flags)) {
 		if (fence_add_callback(sync_file->fence, &sync_file->cb,
-				       fence_check_cb_func) < 0)
+					   fence_check_cb_func) < 0)
 			wake_up_all(&sync_file->wq);
 	}
 
@@ -370,7 +365,7 @@
 	return err;
 }
 
-static void sync_fill_fence_info(struct fence *fence,
+static int sync_fill_fence_info(struct fence *fence,
 				 struct sync_fence_info *info)
 {
 	strlcpy(info->obj_name, fence->ops->get_timeline_name(fence),
@@ -382,6 +377,8 @@
 	else
 		info->status = 0;
 	info->timestamp_ns = ktime_to_ns(fence->timestamp);
+
+	return info->status;
 }
 
 static long sync_file_ioctl_fence_info(struct sync_file *sync_file,
@@ -407,8 +404,12 @@
 	 * sync_fence_info and return the actual number of fences on
 	 * info->num_fences.
 	 */
-	if (!info.num_fences)
+	if (!info.num_fences) {
+		info.status = fence_is_signaled(sync_file->fence);
 		goto no_fences;
+	} else {
+		info.status = 1;
+	}
 
 	if (info.num_fences < num_fences)
 		return -EINVAL;
@@ -418,8 +419,10 @@
 	if (!fence_info)
 		return -ENOMEM;
 
-	for (i = 0; i < num_fences; i++)
-		sync_fill_fence_info(fences[i], &fence_info[i]);
+	for (i = 0; i < num_fences; i++) {
+		int status = sync_fill_fence_info(fences[i], &fence_info[i]);
+		info.status = info.status <= 0 ? info.status : status;
+	}
 
 	if (copy_to_user(u64_to_user_ptr(info.sync_fence_info), fence_info,
 			 size)) {
@@ -429,7 +432,6 @@
 
 no_fences:
 	strlcpy(info.name, sync_file->name, sizeof(info.name));
-	info.status = fence_is_signaled(sync_file->fence);
 	info.num_fences = num_fences;
 
 	if (copy_to_user((void __user *)arg, &info, sizeof(info)))
@@ -443,12 +445,26 @@
 	return ret;
 }
 
+#define SYNC_IOC_WAIT          _IOW(SYNC_IOC_MAGIC, 0, __s32)
+static long sync_fence_ioctl_wait(struct sync_file *sync_file, unsigned long arg)
+{
+       __s32 value;
+
+       if (copy_from_user(&value, (void __user *)arg, sizeof(value)))
+               return -EFAULT;
+        if(value <= 0)
+                       value = MAX_SCHEDULE_TIMEOUT;
+       return fence_wait_timeout(sync_file->fence, true, value);
+}
+
 static long sync_file_ioctl(struct file *file, unsigned int cmd,
 			    unsigned long arg)
 {
 	struct sync_file *sync_file = file->private_data;
 
 	switch (cmd) {
+	case SYNC_IOC_WAIT:
+       return sync_fence_ioctl_wait(sync_file, arg);
 	case SYNC_IOC_MERGE:
 		return sync_file_ioctl_merge(sync_file, arg);