dm:simple_strtoul() cleanup.

index 3f06df5..e2b3240 100644
@@ -1241,7 +1241,6 @@ static void kcryptd_queue_crypt(struct dm_crypt_io *io)
 static int crypt_decode_key(u8 *key, char *hex, unsigned int size)
 {
 	char buffer[3];
-	char *endp;
 	unsigned int i;
 
 	buffer[2] = '\0';

@@ -1250,9 +1249,7 @@ static int crypt_decode_key(u8 *key, char *hex, unsigned int size)
 		buffer[0] = *hex++;
 		buffer[1] = *hex++;
 
-		key[i] = (u8)simple_strtoul(buffer, &endp, 16);
-
-		if (endp != &buffer[2])
+		if (kstrtou8(buffer, 16, &key[i]))
 			return -EINVAL;
 	}
 

index aa70f7d..cf583bc 100644
@@ -143,11 +143,9 @@ static int set_chunk_size(struct dm_exception_store *store,
 			  const char *chunk_size_arg, char **error)
 {
 	unsigned long chunk_size_ulong;
-	char *value;
 
-	chunk_size_ulong = simple_strtoul(chunk_size_arg, &value, 10);
-	if (*chunk_size_arg == '\0' || *value != '\0' ||
-	    chunk_size_ulong > UINT_MAX) {
+	if (kstrtoul(chunk_size_arg, 10, &chunk_size_ulong) ||
+			chunk_size_ulong > UINT_MAX) {
 		*error = "Invalid chunk size";
 		return -EINVAL;
 	}

index 35c94ff..183db5d 100644
@@ -99,7 +99,6 @@ static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	sector_t width;
 	uint32_t stripes;
 	uint32_t chunk_size;
-	char *end;
 	int r;
 	unsigned int i;
 

@@ -108,14 +107,12 @@ static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 		return -EINVAL;
 	}
 
-	stripes = simple_strtoul(argv[0], &end, 10);
-	if (!stripes || *end) {
+	if (kstrtouint(argv[0], 10, &stripes) || !stripes) {
 		ti->error = "Invalid stripe count";
 		return -EINVAL;
 	}
 
-	chunk_size = simple_strtoul(argv[1], &end, 10);
-	if (*end) {
+	if (kstrtouint(argv[1], 10, &chunk_size)) {
 		ti->error = "Invalid chunk_size";
 		return -EINVAL;
 	}