diff --git a/examples/nvme/fio_plugin/fio_plugin.c b/examples/nvme/fio_plugin/fio_plugin.c
index 7785c3993..d5b3596b5 100644
--- a/examples/nvme/fio_plugin/fio_plugin.c
+++ b/examples/nvme/fio_plugin/fio_plugin.c
@@ -101,12 +101,12 @@ struct spdk_fio_thread {
 	struct thread_data	*td;
 
 	struct spdk_fio_qpair	*fio_qpair;
-	struct spdk_fio_qpair	*fio_qpair_current; // the current fio_qpair to be handled.
+	struct spdk_fio_qpair	*fio_qpair_current;	/* the current fio_qpair to be handled. */
 
-	struct io_u		**iocq;	// io completion queue
-	unsigned int		iocq_count;	// number of iocq entries filled by last getevents
-	unsigned int		iocq_size;	// number of iocq entries allocated
-	struct fio_file		*current_f;   // fio_file given by user
+	struct io_u		**iocq;		/* io completion queue */
+	unsigned int		iocq_count;	/* number of iocq entries filled by last getevents */
+	unsigned int		iocq_size;	/* number of iocq entries allocated */
+	struct fio_file		*current_f;	/* fio_file given by user */
 
 };
 
@@ -690,7 +690,7 @@ spdk_fio_queue(struct thread_data *td, struct io_u *io_u)
 	lba = io_u->offset / block_size;
 	lba_count = io_u->xfer_buflen / block_size;
 
-	// TODO: considering situations that fio will randomize and verify io_u
+	/* TODO: considering situations that fio will randomize and verify io_u */
 	if (fio_qpair->do_nvme_pi) {
 		fio_extended_lba_setup_pi(fio_qpair, io_u);
 	}
diff --git a/lib/nvme/nvme_ctrlr_ocssd_cmd.c b/lib/nvme/nvme_ctrlr_ocssd_cmd.c
index 80de53281..b97bfc041 100644
--- a/lib/nvme/nvme_ctrlr_ocssd_cmd.c
+++ b/lib/nvme/nvme_ctrlr_ocssd_cmd.c
@@ -38,8 +38,9 @@ bool
 spdk_nvme_ctrlr_is_ocssd_supported(struct spdk_nvme_ctrlr *ctrlr)
 {
 	if (ctrlr->quirks & NVME_QUIRK_OCSSD) {
-		// TODO: There isn't a standardized way to identify Open-Channel SSD
-		// different verdors may have different conditions.
+		/* TODO: There isn't a standardized way to identify Open-Channel SSD
+		 * different verdors may have different conditions.
+		 */
 
 		/*
 		 * Current QEMU OpenChannel Device needs to check nsdata->vs[0].
diff --git a/test/unit/lib/nvme/nvme_qpair.c/nvme_qpair_ut.c b/test/unit/lib/nvme/nvme_qpair.c/nvme_qpair_ut.c
index 11fea8c71..c39ae7928 100644
--- a/test/unit/lib/nvme/nvme_qpair.c/nvme_qpair_ut.c
+++ b/test/unit/lib/nvme/nvme_qpair.c/nvme_qpair_ut.c
@@ -77,14 +77,14 @@ nvme_transport_qpair_fail(struct spdk_nvme_qpair *qpair)
 int
 nvme_transport_qpair_submit_request(struct spdk_nvme_qpair *qpair, struct nvme_request *req)
 {
-	// TODO
+	/* TODO */
 	return 0;
 }
 
 int32_t
 nvme_transport_qpair_process_completions(struct spdk_nvme_qpair *qpair, uint32_t max_completions)
 {
-	// TODO
+	/* TODO */
 	return 0;
 }