Index: head/sbin/nvmecontrol/devlist.c
===================================================================
--- head/sbin/nvmecontrol/devlist.c	(revision 342357)
+++ head/sbin/nvmecontrol/devlist.c	(revision 342358)
@@ -1,123 +1,123 @@
 /*-
  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
  *
  * Copyright (C) 2012-2013 Intel Corporation
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
 
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
 
 #include <err.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <paths.h>
 #include <stddef.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 
 #include "nvmecontrol.h"
 
 #define DEVLIST_USAGE							       \
 	"devlist\n"
 
+#define NVME_MAX_UNIT 256
+
 static inline uint32_t
 ns_get_sector_size(struct nvme_namespace_data *nsdata)
 {
 	uint8_t flbas_fmt, lbads;
 
 	flbas_fmt = (nsdata->flbas >> NVME_NS_DATA_FLBAS_FORMAT_SHIFT) &
 		NVME_NS_DATA_FLBAS_FORMAT_MASK;
 	lbads = (nsdata->lbaf[flbas_fmt] >> NVME_NS_DATA_LBAF_LBADS_SHIFT) &
 		NVME_NS_DATA_LBAF_LBADS_MASK;
 
 	return (1 << lbads);
 }
 
 static void
 devlist(const struct nvme_function *nf, int argc, char *argv[])
 {
 	struct nvme_controller_data	cdata;
 	struct nvme_namespace_data	nsdata;
 	char				name[64];
 	uint8_t				mn[64];
 	uint32_t			i;
 	int				ch, ctrlr, fd, found, ret;
 
 	while ((ch = getopt(argc, argv, "")) != -1) {
 		switch ((char)ch) {
 		default:
 			usage(nf);
 		}
 	}
 
 	ctrlr = -1;
 	found = 0;
 
-	while (1) {
+	while (ctrlr < NVME_MAX_UNIT) {
 		ctrlr++;
 		sprintf(name, "%s%d", NVME_CTRLR_PREFIX, ctrlr);
 
 		ret = open_dev(name, &fd, 0, 0);
 
-		if (ret != 0) {
-			if (ret == EACCES) {
-				warnx("could not open "_PATH_DEV"%s\n", name);
-				continue;
-			} else
-				break;
-		}
+		if (ret == EACCES) {
+			warnx("could not open "_PATH_DEV"%s\n", name);
+			continue;
+		} else if (ret != 0)
+			continue;
 
 		found++;
 		read_controller_data(fd, &cdata);
 		nvme_strvis(mn, cdata.mn, sizeof(mn), NVME_MODEL_NUMBER_LENGTH);
 		printf("%6s: %s\n", name, mn);
 
 		for (i = 0; i < cdata.nn; i++) {
 			sprintf(name, "%s%d%s%d", NVME_CTRLR_PREFIX, ctrlr,
 			    NVME_NS_PREFIX, i+1);
 			read_namespace_data(fd, i+1, &nsdata);
 			if (nsdata.nsze == 0)
 				continue;
 			printf("  %10s (%lldMB)\n",
 				name,
 				nsdata.nsze *
 				(long long)ns_get_sector_size(&nsdata) /
 				1024 / 1024);
 		}
 
 		close(fd);
 	}
 
 	if (found == 0)
 		printf("No NVMe controllers found.\n");
 
 	exit(1);
 }
 
 NVME_COMMAND(top, devlist, devlist, DEVLIST_USAGE);