diff --git a/drivers/mmc/card/mmc_test.c b/drivers/mmc/card/mmc_test.c
index a69df5216274..0c0fc52d42c5 100644
--- a/drivers/mmc/card/mmc_test.c
+++ b/drivers/mmc/card/mmc_test.c
@@ -2849,18 +2849,12 @@ static ssize_t mtf_test_write(struct file *file, const char __user *buf,
 	struct seq_file *sf = (struct seq_file *)file->private_data;
 	struct mmc_card *card = (struct mmc_card *)sf->private;
 	struct mmc_test_card *test;
-	char lbuf[12];
 	long testcase;
+	int ret;
 
-	if (count >= sizeof(lbuf))
-		return -EINVAL;
-
-	if (copy_from_user(lbuf, buf, count))
-		return -EFAULT;
-	lbuf[count] = '\0';
-
-	if (strict_strtol(lbuf, 10, &testcase))
-		return -EINVAL;
+	ret = kstrtol_from_user(buf, count, 10, &testcase);
+	if (ret)
+		return ret;
 
 	test = kzalloc(sizeof(struct mmc_test_card), GFP_KERNEL);
 	if (!test)