diff --git a/src/nvme/ioctl.c b/src/nvme/ioctl.c
index 8649a74c..8d88af12 100644
--- a/src/nvme/ioctl.c
+++ b/src/nvme/ioctl.c
@@ -114,112 +114,6 @@ static void nvme_show_command(struct nvme_passthru_cmd *cmd, int err)
 	printf("err          : %d\n", err);
 }
 
-const char *nvme_admin_to_string(__u8 opcode)
-{
-	switch (opcode) {
-	case nvme_admin_delete_sq:
-		return "Delete I/O Submission Queue";
-	case nvme_admin_create_sq:
-		return "Create I/O Submission Queue";
-	case nvme_admin_get_log_page:
-		return "Get Log Page";
-	case nvme_admin_delete_cq:
-		return "Delete I/O Completion Queue";
-	case nvme_admin_create_cq:
-		return "Create I/O Completion Queue";
-	case nvme_admin_identify:
-		return "Identify";
-	case nvme_admin_abort_cmd:
-		return "Abort";
-	case nvme_admin_set_features:
-		return "Set Features";
-	case nvme_admin_get_features:
-		return "Get Features";
-	case nvme_admin_async_event:
-		return "Asynchronous Event Request";
-	case nvme_admin_ns_mgmt:
-		return "Namespace Management";
-	case nvme_admin_fw_commit:
-		return "Firmware Commit";
-	case nvme_admin_fw_download:
-		return "Firmware Image Download";
-	case nvme_admin_dev_self_test:
-		return "Device Self-test";
-	case nvme_admin_ns_attach:
-		return "Namespace Attachment";
-	case nvme_admin_keep_alive:
-		return "Keep Alive";
-	case nvme_admin_directive_send:
-		return "Directive Send";
-	case nvme_admin_directive_recv:
-		return "Directive Receive";
-	case nvme_admin_virtual_mgmt:
-		return "Virtualization Management";
-	case nvme_admin_nvme_mi_send:
-		return "NVMe-MI Send";
-	case nvme_admin_nvme_mi_recv:
-		return "NVMe-MI Receive";
-	case nvme_admin_dbbuf:
-		return "Doorbell Buffer Config";
-	case nvme_admin_format_nvm:
-		return "Format NVM";
-	case nvme_admin_security_send:
-		return "Security Send";
-	case nvme_admin_security_recv:
-		return "Security Receive";
-	case nvme_admin_sanitize_nvm:
-		return "Sanitize";
-	case nvme_admin_get_lba_status:
-		return "Get LBA Status";
-	default:
-		break;
-	}
-
-	return NULL;
-}
-
-const char *nvme_nvm_to_string(__u8 opcode)
-{
-	switch (opcode) {
-	case nvme_cmd_flush:
-		return "Flush";
-	case nvme_cmd_write:
-		return "Write";
-	case nvme_cmd_read:
-		return "Read";
-	case nvme_cmd_write_uncor:
-		return "Write Uncorrectable";
-	case nvme_cmd_compare:
-		return "Compare";
-	case nvme_cmd_write_zeroes:
-		return "Write Zeroes";
-	case nvme_cmd_dsm:
-		return "Dataset Management";
-	case nvme_cmd_resv_register:
-		return "Reservation Register";
-	case nvme_cmd_resv_report:
-		return "Reservation Report";
-	case nvme_cmd_resv_acquire:
-		return "Reservation Acquire";
-	case nvme_cmd_resv_release:
-		return "Reservation Release";
-	case nvme_cmd_verify:
-		return "Verify";
-	case nvme_cmd_copy:
-		return "Copy";
-	case nvme_zns_cmd_mgmt_send:
-		return "Zone Management Send";
-	case nvme_zns_cmd_mgmt_recv:
-		return "Zone Management Receive";
-	case nvme_zns_cmd_append:
-		return "Zone Append";
-	default:
-		break;
-	}
-
-	return NULL;
-}
-
 static const char *nvme_cmd_to_string(bool admin, __u8 opcode)
 {
 	const char *cmd_name;
diff --git a/src/nvme/ioctl.h b/src/nvme/ioctl.h
index bdb22b3f..f48b5b44 100644
--- a/src/nvme/ioctl.h
+++ b/src/nvme/ioctl.h
@@ -4072,22 +4072,4 @@ void nvme_set_latency(bool latency);
  * Return: false if disabled or true if enabled.
  */
 bool nvme_get_latency(void);
-
-/**
- * nvme_admin_to_string - Returns string describing nvme admin opcode
- * @opcode:  Admin opcode for an nvme command
- *
- * Return: representation of the admin opcode if it is an admin opcode field,
- * or NULL if opcode is unknown.
- */
-const char *nvme_admin_to_string(__u8 opcode);
-
-/**
- * nvme_nvm_to_string - Returns string describing nvme nvm opcode
- * @opcode:  NVM opcode for an nvme command
- *
- * Return: representation of the nvm opcode if it is an nvm opcode field,
- * or NULL if opcode is unknown.
- */
-const char *nvme_nvm_to_string(__u8 opcode);
 #endif /* _LIBNVME_IOCTL_H */
diff --git a/src/nvme/util.c b/src/nvme/util.c
index 45512ff9..bf3946c0 100644
--- a/src/nvme/util.c
+++ b/src/nvme/util.c
@@ -1116,3 +1116,68 @@ void *__nvme_alloc(size_t len)
 	memset(p, 0, _len);
 	return p;
 }
+
+static const char * const admin_opcode[] = {
+	[nvme_admin_delete_sq] = "Delete I/O Submission Queue",
+	[nvme_admin_create_sq] = "Create I/O Submission Queue",
+	[nvme_admin_get_log_page] = "Get Log Page",
+	[nvme_admin_delete_cq] = "Delete I/O Completion Queue",
+	[nvme_admin_create_cq] = "Create I/O Completion Queue",
+	[nvme_admin_identify] = "Identify",
+	[nvme_admin_abort_cmd] = "Abort",
+	[nvme_admin_set_features] = "Set Features",
+	[nvme_admin_get_features] = "Get Features",
+	[nvme_admin_async_event] = "Asynchronous Event Request",
+	[nvme_admin_ns_mgmt] = "Namespace Management",
+	[nvme_admin_fw_commit] = "Firmware Commit",
+	[nvme_admin_fw_download] = "Firmware Image Download",
+	[nvme_admin_dev_self_test] = "Device Self-test",
+	[nvme_admin_ns_attach] = "Namespace Attachment",
+	[nvme_admin_keep_alive] = "Keep Alive",
+	[nvme_admin_directive_send] = "Directive Send",
+	[nvme_admin_directive_recv] = "Directive Receive",
+	[nvme_admin_virtual_mgmt] = "Virtualization Management",
+	[nvme_admin_nvme_mi_send] = "NVMe-MI Send",
+	[nvme_admin_nvme_mi_recv] = "NVMe-MI Receive",
+	[nvme_admin_dbbuf] = "Doorbell Buffer Config",
+	[nvme_admin_format_nvm] = "Format NVM",
+	[nvme_admin_security_send] = "Security Send",
+	[nvme_admin_security_recv] = "Security Receive",
+	[nvme_admin_sanitize_nvm] = "Sanitize",
+	[nvme_admin_get_lba_status] = "Get LBA Status",
+};
+
+static const char * const nvm_opcode[] = {
+	[nvme_cmd_flush] = "Flush",
+	[nvme_cmd_write] = "Write",
+	[nvme_cmd_read] = "Read",
+	[nvme_cmd_write_uncor] = "Write Uncorrectable",
+	[nvme_cmd_compare] = "Compare",
+	[nvme_cmd_write_zeroes] = "Write Zeroes",
+	[nvme_cmd_dsm] = "Dataset Management",
+	[nvme_cmd_resv_register] = "Reservation Register",
+	[nvme_cmd_resv_report] = "Reservation Report",
+	[nvme_cmd_resv_acquire] = "Reservation Acquire",
+	[nvme_cmd_resv_release] = "Reservation Release",
+	[nvme_cmd_verify] = "Verify",
+	[nvme_cmd_copy] = "Copy",
+	[nvme_zns_cmd_mgmt_send] = "Zone Management Send",
+	[nvme_zns_cmd_mgmt_recv] = "Zone Management Receive",
+	[nvme_zns_cmd_append] = "Zone Append",
+};
+
+const char *nvme_admin_to_string(__u8 opcode)
+{
+	if (opcode < ARRAY_SIZE(admin_opcode))
+		return admin_opcode[opcode];
+
+	return NULL;
+}
+
+const char *nvme_nvm_to_string(__u8 opcode)
+{
+	if (opcode < ARRAY_SIZE(nvm_opcode))
+		return nvm_opcode[opcode];
+
+	return NULL;
+}
diff --git a/src/nvme/util.h b/src/nvme/util.h
index 16d5b9ca..bf91302e 100644
--- a/src/nvme/util.h
+++ b/src/nvme/util.h
@@ -702,4 +702,21 @@ const char *nvme_iface_matching_addr(const struct ifaddrs *iface_list, const cha
  */
 bool nvme_iface_primary_addr_matches(const struct ifaddrs *iface_list, const char *iface, const char *addr);
 
+/**
+ * nvme_admin_to_string - Returns string describing nvme admin opcode
+ * @opcode:  Admin opcode for an nvme command
+ *
+ * Return: representation of the admin opcode if it is an admin opcode field,
+ * or NULL if opcode is unknown.
+ */
+const char *nvme_admin_to_string(__u8 opcode);
+
+/**
+ * nvme_nvm_to_string - Returns string describing nvme nvm opcode
+ * @opcode:  NVM opcode for an nvme command
+ *
+ * Return: representation of the nvm opcode if it is an nvm opcode field,
+ * or NULL if opcode is unknown.
+ */
+const char *nvme_nvm_to_string(__u8 opcode);
 #endif /* _LIBNVME_UTIL_H */