msm: camera: core: Fix context release timing issue

When sync object is invalid and num_in_map > 1,
it will lead to context ref leak. Check sync
object first, then register sync call back.

CRs-Fixed: 2594185
Change-Id: I2d39ce3ea43bbe7bc05420b86b37fdfba4aa795a
Signed-off-by: Ayush Kumar <ayushkr@codeaurora.org>

drivers/cam_sync/cam_sync_api.h

@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 /*
- * Copyright (c) 2017-2019, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2017-2020, The Linux Foundation. All rights reserved.
  */
 
 #ifndef __CAM_SYNC_API_H__
@@ -140,6 +140,16 @@ int cam_sync_destroy(int32_t sync_obj);
  */
 int cam_sync_wait(int32_t sync_obj, uint64_t timeout_ms);
 
+/**
+ * @brief: Check if sync object is valid
+ *
+ * @param sync_obj: int referencing the sync object to be checked
+ *
+ * @return 0 upon success, -EINVAL if sync object is in bad state or arguments
+ * are invalid
+ */
+int cam_sync_check_valid(int32_t sync_obj);
+
 /**
  * @brief : API to register SYNC to platform framework.
  * @return struct platform_device pointer on on success, or ERR_PTR() on error.