diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index 097315a9bf0f..33dbc71b730f 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -16,6 +16,7 @@
 #include <linux/dm-kcopyd.h>
 #include <linux/jiffies.h>
 #include <linux/init.h>
+#include <linux/kstrtox.h>
 #include <linux/mempool.h>
 #include <linux/module.h>
 #include <linux/rwsem.h>
@@ -3311,42 +3312,46 @@ struct cblock_range {
 	dm_cblock_t end;
 };
 
+static inline dm_cblock_t cblock_succ(dm_cblock_t b)
+{
+	return to_cblock(from_cblock(b) + 1);
+}
+
 /*
  * A cache block range can take two forms:
  *
  * i) A single cblock, eg. '3456'
  * ii) A begin and end cblock with a dash between, eg. 123-234
  */
-static int parse_cblock_range(struct cache *cache, const char *str,
+static int parse_cblock_range(struct cache *cache, char *str,
 			      struct cblock_range *result)
 {
-	char dummy;
-	uint64_t b, e;
+	char *blocknr = strsep(&str, "-");
+	unsigned int b, e;
 	int r;
 
-	/*
-	 * Try and parse form (ii) first.
-	 */
-	r = sscanf(str, "%llu-%llu%c", &b, &e, &dummy);
+	r = kstrtouint(blocknr, 10, &b);
+	if (r)
+		goto bad;
+
+	result->begin = to_cblock(b);
+
+	if (str) {
+		blocknr = str;
+
+		r = kstrtouint(blocknr, 10, &e);
+		if (r)
+			goto bad;
 
-	if (r == 2) {
-		result->begin = to_cblock(b);
 		result->end = to_cblock(e);
-		return 0;
+	} else {
+		result->end = cblock_succ(result->begin);
 	}
 
-	/*
-	 * That didn't work, try form (i).
-	 */
-	r = sscanf(str, "%llu%c", &b, &dummy);
+	return 0;
 
-	if (r == 1) {
-		result->begin = to_cblock(b);
-		result->end = to_cblock(from_cblock(result->begin) + 1u);
-		return 0;
-	}
-
-	DMERR("%s: invalid cblock range '%s'", cache_device_name(cache), str);
+bad:
+	DMERR("%s: invalid cblock range '%s'", cache_device_name(cache), blocknr);
 	return -EINVAL;
 }
 
@@ -3377,11 +3382,6 @@ static int validate_cblock_range(struct cache *cache, struct cblock_range *range
 	return 0;
 }
 
-static inline dm_cblock_t cblock_succ(dm_cblock_t b)
-{
-	return to_cblock(from_cblock(b) + 1);
-}
-
 static int request_invalidation(struct cache *cache, struct cblock_range *range)
 {
 	int r = 0;
@@ -3405,7 +3405,7 @@ static int request_invalidation(struct cache *cache, struct cblock_range *range)
 }
 
 static int process_invalidate_cblocks_message(struct cache *cache, unsigned int count,
-					      const char **cblock_ranges)
+					      char **cblock_ranges)
 {
 	int r = 0;
 	unsigned int i;
@@ -3460,7 +3460,7 @@ static int cache_message(struct dm_target *ti, unsigned int argc, char **argv,
 	}
 
 	if (!strcasecmp(argv[0], "invalidate_cblocks"))
-		return process_invalidate_cblocks_message(cache, argc - 1, (const char **) argv + 1);
+		return process_invalidate_cblocks_message(cache, argc - 1, argv + 1);
 
 	if (argc != 2)
 		return -EINVAL;