Index: head/sbin/nvmecontrol/devlist.c
===================================================================
--- head/sbin/nvmecontrol/devlist.c
+++ head/sbin/nvmecontrol/devlist.c
@@ -60,7 +60,7 @@
 }
 
 static void
-devlist(struct nvme_function *nf, int argc, char *argv[])
+devlist(const struct nvme_function *nf, int argc, char *argv[])
 {
 	struct nvme_controller_data	cdata;
 	struct nvme_namespace_data	nsdata;
Index: head/sbin/nvmecontrol/firmware.c
===================================================================
--- head/sbin/nvmecontrol/firmware.c
+++ head/sbin/nvmecontrol/firmware.c
@@ -174,7 +174,7 @@
 }
 
 static void
-firmware(struct nvme_function *nf, int argc, char *argv[])
+firmware(const struct nvme_function *nf, int argc, char *argv[])
 {
 	int				fd = -1, slot = 0;
 	int				a_flag, s_flag, f_flag;
Index: head/sbin/nvmecontrol/format.c
===================================================================
--- head/sbin/nvmecontrol/format.c
+++ head/sbin/nvmecontrol/format.c
@@ -47,7 +47,7 @@
 	"format [-f fmt] [-m mset] [-p pi] [-l pil] [-E] [-C] <controller id|namespace id>\n"
 
 static void
-format(struct nvme_function *nf, int argc, char *argv[])
+format(const struct nvme_function *nf, int argc, char *argv[])
 {
 	struct nvme_controller_data	cd;
 	struct nvme_namespace_data	nsd;
Index: head/sbin/nvmecontrol/identify.c
===================================================================
--- head/sbin/nvmecontrol/identify.c
+++ head/sbin/nvmecontrol/identify.c
@@ -150,7 +150,7 @@
 }
 
 static void
-identify_ctrlr(struct nvme_function *nf, int argc, char *argv[])
+identify_ctrlr(const struct nvme_function *nf, int argc, char *argv[])
 {
 	struct nvme_controller_data	cdata;
 	int				ch, fd, hexflag = 0, hexlength;
@@ -197,7 +197,7 @@
 }
 
 static void
-identify_ns(struct nvme_function *nf,int argc, char *argv[])
+identify_ns(const struct nvme_function *nf,int argc, char *argv[])
 {
 	struct nvme_namespace_data	nsdata;
 	char				path[64];
@@ -261,7 +261,7 @@
 }
 
 static void
-identify(struct nvme_function *nf, int argc, char *argv[])
+identify(const struct nvme_function *nf, int argc, char *argv[])
 {
 	char	*target;
 
Index: head/sbin/nvmecontrol/logpage.c
===================================================================
--- head/sbin/nvmecontrol/logpage.c
+++ head/sbin/nvmecontrol/logpage.c
@@ -326,7 +326,7 @@
 static void
 logpage_help(void)
 {
-	struct logpage_function		**f;
+	const struct logpage_function	* const *f;
 	const char 			*v;
 
 	fprintf(stderr, "\n");
@@ -341,7 +341,7 @@
 }
 
 static void
-logpage(struct nvme_function *nf, int argc, char *argv[])
+logpage(const struct nvme_function *nf, int argc, char *argv[])
 {
 	int				fd;
 	int				log_page = 0, pageflag = false;
@@ -352,7 +352,7 @@
 	uint32_t			nsid, size;
 	void				*buf;
 	const char			*vendor = NULL;
-	struct logpage_function		**f;
+	const struct logpage_function	* const *f;
 	struct nvme_controller_data	cdata;
 	print_fn_t			print_fn;
 	uint8_t				ns_smart;
Index: head/sbin/nvmecontrol/ns.c
===================================================================
--- head/sbin/nvmecontrol/ns.c
+++ head/sbin/nvmecontrol/ns.c
@@ -60,10 +60,10 @@
 #define NSDETACH_USAGE							\
 	"ns detach -n nsid [-c ctrlrid] nvmeN\n"
 
-void nscreate(struct nvme_function *nf, int argc, char *argv[]);
-void nsdelete(struct nvme_function *nf, int argc, char *argv[]);
-void nsattach(struct nvme_function *nf, int argc, char *argv[]);
-void nsdetach(struct nvme_function *nf, int argc, char *argv[]);
+static void nscreate(const struct nvme_function *nf, int argc, char *argv[]);
+static void nsdelete(const struct nvme_function *nf, int argc, char *argv[]);
+static void nsattach(const struct nvme_function *nf, int argc, char *argv[]);
+static void nsdetach(const struct nvme_function *nf, int argc, char *argv[]);
 
 NVME_COMMAND(ns, create, nscreate, NSCREATE_USAGE);
 NVME_COMMAND(ns, delete, nsdelete, NSDELETE_USAGE);
@@ -109,8 +109,8 @@
  * 0x16 = Namespace ID  unavailable (number namespaces exceeded)
  * 0xb = Thin Provisioning Not supported
  */
-void
-nscreate(struct nvme_function *nf, int argc, char *argv[])
+static void
+nscreate(const struct nvme_function *nf, int argc, char *argv[])
 {
 	struct nvme_pt_command	pt;
 	struct nvme_controller_data cd;
@@ -204,8 +204,8 @@
 	exit(0);
 }
 
-void
-nsdelete(struct nvme_function *nf, int argc, char *argv[])
+static void
+nsdelete(const struct nvme_function *nf, int argc, char *argv[])
 {
 	struct nvme_pt_command	pt;
 	struct nvme_controller_data cd;
@@ -271,8 +271,8 @@
  *
  * 0x2 Invalid Field can occur if ctrlrid d.n.e in system.
  */
-void
-nsattach(struct nvme_function *nf, int argc, char *argv[])
+static void
+nsattach(const struct nvme_function *nf, int argc, char *argv[])
 {
 	struct nvme_pt_command	pt;
 	struct nvme_controller_data cd;
@@ -350,8 +350,8 @@
 	exit(0);
 }
 
-void
-nsdetach(struct nvme_function *nf, int argc, char *argv[])
+static void
+nsdetach(const struct nvme_function *nf, int argc, char *argv[])
 {
 	struct nvme_pt_command	pt;
 	struct nvme_controller_data cd;
@@ -437,7 +437,7 @@
 }
 
 static void
-ns(struct nvme_function *nf __unused, int argc, char *argv[])
+ns(const struct nvme_function *nf __unused, int argc, char *argv[])
 {
 
 	DISPATCH(argc, argv, ns);
Index: head/sbin/nvmecontrol/nvmecontrol.h
===================================================================
--- head/sbin/nvmecontrol/nvmecontrol.h
+++ head/sbin/nvmecontrol/nvmecontrol.h
@@ -35,7 +35,7 @@
 #include <dev/nvme/nvme.h>
 
 struct nvme_function;
-typedef void (*nvme_fn_t)(struct nvme_function *nf, int argc, char *argv[]);
+typedef void (*nvme_fn_t)(const struct nvme_function *nf, int argc, char *argv[]);
 
 struct nvme_function {
 	const char	*name;
@@ -96,8 +96,8 @@
 void set_concat_add(struct set_concat *m, void *begin, void *end);
 #define SET_CONCAT_DEF(set, t) 							\
 static struct set_concat set ## _concat;					\
-static inline t **set ## _begin() { return ((t **)set ## _concat.begin); }	\
-static inline t **set ## _limit() { return ((t **)set ## _concat.limit); }	\
+static inline const t * const *set ## _begin() { return ((const t * const *)set ## _concat.begin); }	\
+static inline const t * const *set ## _limit() { return ((const t * const *)set ## _concat.limit); }	\
 void add_to_ ## set(t **b, t **e)						\
 {										\
 	set_concat_add(&set ## _concat, b, e);					\
@@ -120,11 +120,13 @@
 void print_temp(uint16_t t);
 
 void usage(const struct nvme_function *f);
-void dispatch_set(int argc, char *argv[], struct nvme_function **tbl,
-    struct nvme_function **tbl_limit);
+void dispatch_set(int argc, char *argv[], const struct nvme_function * const *tbl,
+    const struct nvme_function * const *tbl_limit);
 
-#define DISPATCH(argc, argv, set)	\
-	dispatch_set(argc, argv, NVME_CMD_BEGIN(set), NVME_CMD_LIMIT(set))
+#define DISPATCH(argc, argv, set)					\
+	dispatch_set(argc, argv,					\
+	    (const struct nvme_function * const *)NVME_CMD_BEGIN(set),	\
+	    (const struct nvme_function * const *)NVME_CMD_LIMIT(set))	\
 
 /* Utility Routines */
 /*
Index: head/sbin/nvmecontrol/nvmecontrol.c
===================================================================
--- head/sbin/nvmecontrol/nvmecontrol.c
+++ head/sbin/nvmecontrol/nvmecontrol.c
@@ -75,7 +75,7 @@
 }
 
 static void
-gen_usage_set(struct nvme_function **f, struct nvme_function **flimit)
+gen_usage_set(const struct nvme_function * const *f, const struct nvme_function * const *flimit)
 {
 
 	fprintf(stderr, "usage:\n");
@@ -96,10 +96,10 @@
 }
 
 void
-dispatch_set(int argc, char *argv[], struct nvme_function **tbl,
-    struct nvme_function **tbl_limit)
+dispatch_set(int argc, char *argv[], const struct nvme_function * const *tbl,
+    const struct nvme_function * const *tbl_limit)
 {
-	struct nvme_function **f = tbl;
+	const struct nvme_function * const *f = tbl;
 
 	if (argv[1] == NULL) {
 		gen_usage_set(tbl, tbl_limit);
Index: head/sbin/nvmecontrol/perftest.c
===================================================================
--- head/sbin/nvmecontrol/perftest.c
+++ head/sbin/nvmecontrol/perftest.c
@@ -75,7 +75,7 @@
 }
 
 static void
-perftest(struct nvme_function *nf, int argc, char *argv[])
+perftest(const struct nvme_function *nf, int argc, char *argv[])
 {
 	struct nvme_io_test		io_test;
 	int				fd;
Index: head/sbin/nvmecontrol/power.c
===================================================================
--- head/sbin/nvmecontrol/power.c
+++ head/sbin/nvmecontrol/power.c
@@ -129,7 +129,7 @@
 }
 
 static void
-power(struct nvme_function *nf, int argc, char *argv[])
+power(const struct nvme_function *nf, int argc, char *argv[])
 {
 	struct nvme_controller_data	cdata;
 	int				ch, listflag = 0, powerflag = 0, power_val = 0, fd;
Index: head/sbin/nvmecontrol/reset.c
===================================================================
--- head/sbin/nvmecontrol/reset.c
+++ head/sbin/nvmecontrol/reset.c
@@ -45,7 +45,7 @@
 	"reset <controller id>\n"
 
 static void
-reset(struct nvme_function *nf, int argc, char *argv[])
+reset(const struct nvme_function *nf, int argc, char *argv[])
 {
 	int	ch, fd;
 
Index: head/sbin/nvmecontrol/wdc.c
===================================================================
--- head/sbin/nvmecontrol/wdc.c
+++ head/sbin/nvmecontrol/wdc.c
@@ -52,7 +52,7 @@
 #define WDC_NVME_CAP_DIAG_OPCODE	0xe6
 #define WDC_NVME_CAP_DIAG_CMD		0x0000
 
-static void wdc_cap_diag(struct nvme_function *nf, int argc, char *argv[]);
+static void wdc_cap_diag(const struct nvme_function *nf, int argc, char *argv[]);
 
 #define WDC_CAP_DIAG_USAGE	"wdc cap-diag [-o path-template]\n"
 
@@ -154,7 +154,7 @@
 }
 
 static void
-wdc_cap_diag(struct nvme_function *nf, int argc, char *argv[])
+wdc_cap_diag(const struct nvme_function *nf, int argc, char *argv[])
 {
 	char path_tmpl[MAXPATHLEN];
 	int ch, fd;
@@ -183,7 +183,7 @@
 }
 
 static void
-wdc(struct nvme_function *nf __unused, int argc, char *argv[])
+wdc(const struct nvme_function *nf __unused, int argc, char *argv[])
 {
 
 	DISPATCH(argc, argv, wdc);