diff --git a/drivers/s390/char/sclp_async.c b/drivers/s390/char/sclp_async.c
index 7ad30e72f868..5f9f929e891c 100644
--- a/drivers/s390/char/sclp_async.c
+++ b/drivers/s390/char/sclp_async.c
@@ -82,12 +82,9 @@ static int proc_handler_callhome(struct ctl_table *ctl, int write,
 			return -EFAULT;
 	} else {
 		len = *count;
-		rc = copy_from_user(buf, buffer, sizeof(buf));
-		if (rc != 0)
-			return -EFAULT;
-		buf[sizeof(buf) - 1] = '\0';
-		if (strict_strtoul(buf, 0, &val) != 0)
-			return -EINVAL;
+		rc = kstrtoul_from_user(buffer, len, 0, &val);
+		if (rc)
+			return rc;
 		if (val != 0 && val != 1)
 			return -EINVAL;
 		callhome_enabled = val;