diff --git a/lib/libgeom/geom_stats.c b/lib/libgeom/geom_stats.c
index 7ae5c947b7b1..510636eb9a8b 100644
--- a/lib/libgeom/geom_stats.c
+++ b/lib/libgeom/geom_stats.c
@@ -1,190 +1,180 @@
 /*-
  * SPDX-License-Identifier: BSD-3-Clause
  *
  * Copyright (c) 2003 Poul-Henning Kamp
  * 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.
  * 3. The names of the authors may not be used to endorse or promote
  *    products derived from this software without specific prior written
  *    permission.
  *
  * 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/types.h>
 #include <sys/ioctl.h>
 #include <sys/disk.h>
 #include <sys/devicestat.h>
 #include <sys/mman.h>
 #include <sys/time.h>
 #include <err.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <paths.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 #include <libgeom.h>
 
 /************************************************************/
 static uint npages, spp;
 static int pagesize, statsfd = -1;
 static u_char *statp;
 
 void
 geom_stats_close(void)
 {
 	if (statsfd == -1)
 		return;
-	munmap(statp, npages * pagesize);
-	statp = NULL;
-	close (statsfd);
+	if (statp != NULL) {
+		if (munmap(statp, npages * pagesize) != 0)
+			err(1, "munmap");
+		statp = NULL;
+	}
+	close(statsfd);
 	statsfd = -1;
 }
 
 void
 geom_stats_resync(void)
 {
 	void *p;
 	off_t mediasize;
 	int error;
 
 	if (statsfd == -1)
 		return;
 	error = ioctl(statsfd, DIOCGMEDIASIZE, &mediasize);
 	if (error)
 		err(1, "DIOCGMEDIASIZE(" _PATH_DEV DEVSTAT_DEVICE_NAME ")");
 
-	munmap(statp, npages * pagesize);
-	p = mmap(statp, mediasize, PROT_READ, MAP_SHARED, statsfd, 0);
+	if (statp != NULL && munmap(statp, npages * pagesize) != 0)
+		err(1, "munmap");
+	p = mmap(NULL, mediasize, PROT_READ, MAP_SHARED, statsfd, 0);
 	if (p == MAP_FAILED)
-		err(1, "mmap(/dev/devstat):");
-	else {
-		statp = p;
-		npages = mediasize / pagesize;
-	}
+		err(1, "mmap(/dev/devstat)");
+	statp = p;
+	npages = mediasize / pagesize;
 }
 
 int
 geom_stats_open(void)
 {
-	int error;
-	void *p;
-
 	if (statsfd != -1)
 		return (EBUSY);
 	statsfd = open(_PATH_DEV DEVSTAT_DEVICE_NAME, O_RDONLY);
 	if (statsfd < 0)
 		return (errno);
 	pagesize = getpagesize();
 	spp = pagesize / sizeof(struct devstat);
-	p = mmap(NULL, pagesize, PROT_READ, MAP_SHARED, statsfd, 0);
-	if (p == MAP_FAILED) {
-		error = errno;
-		close(statsfd);
-		statsfd = -1;
-		errno = error;
-		return (error);
-	}
-	statp = p;
 	npages = 1;
 	geom_stats_resync();
 	return (0);
 }
 
 struct snapshot {
 	u_char		*ptr;
 	uint		pages;
 	uint		pagesize;
 	uint		perpage;
 	struct timespec	time;
 	/* used by getnext: */
 	uint		u, v;
 };
 
 void *
 geom_stats_snapshot_get(void)
 {
 	struct snapshot *sp;
 
 	sp = malloc(sizeof *sp);
 	if (sp == NULL)
 		return (NULL);
 	memset(sp, 0, sizeof *sp);
 	sp->ptr = malloc(pagesize * npages);
 	if (sp->ptr == NULL) {
 		free(sp);
 		return (NULL);
 	}
 	explicit_bzero(sp->ptr, pagesize * npages); 	/* page in, cache */
 	clock_gettime(CLOCK_REALTIME, &sp->time);
 	memcpy(sp->ptr, statp, pagesize * npages);
 	sp->pages = npages;
 	sp->perpage = spp;
 	sp->pagesize = pagesize;
 	return (sp);
 }
 
 void
 geom_stats_snapshot_free(void *arg)
 {
 	struct snapshot *sp;
 
 	sp = arg;
 	free(sp->ptr);
 	free(sp);
 }
 
 void
 geom_stats_snapshot_timestamp(void *arg, struct timespec *tp)
 {
 	struct snapshot *sp;
 
 	sp = arg;
 	*tp = sp->time;
 }
 
 void
 geom_stats_snapshot_reset(void *arg)
 {
 	struct snapshot *sp;
 
 	sp = arg;
 	sp->u = sp->v = 0;
 }
 
 struct devstat *
 geom_stats_snapshot_next(void *arg)
 {
 	struct devstat *gsp;
 	struct snapshot *sp;
 
 	sp = arg;
 	gsp = (struct devstat *)
 	    (sp->ptr + sp->u * pagesize + sp->v * sizeof *gsp);
 	if (++sp->v >= sp->perpage) {
 		if (++sp->u >= sp->pages)
 			return (NULL);
 		else
 			sp->v = 0;
 	}
 	return (gsp);
 }