From 03a97550941d17c7d5b621afde5945bbc0da6546 Mon Sep 17 00:00:00 2001
From: Zhaoxiu Zeng <zhaoxiu.zeng@gmail.com>
Date: Tue, 12 Apr 2016 15:30:35 +0800
Subject: [PATCH] mtd: nand: s3c2410: fix bug in s3c2410_nand_correct_data()

If there is only one bit difference in the ECC, the function should
return 1.
The result of "diff0 & ~(1<<fls(diff0))" is equal to diff0, so the
function actually returns -1.

Signed-off-by: Zhaoxiu Zeng <zhaoxiu.zeng@gmail.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
---
 drivers/mtd/nand/s3c2410.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/nand/s3c2410.c b/drivers/mtd/nand/s3c2410.c
index 9c9397b54b2c..86ffb73e1085 100644
--- a/drivers/mtd/nand/s3c2410.c
+++ b/drivers/mtd/nand/s3c2410.c
@@ -542,7 +542,8 @@ static int s3c2410_nand_correct_data(struct mtd_info *mtd, u_char *dat,
 	diff0 |= (diff1 << 8);
 	diff0 |= (diff2 << 16);
 
-	if ((diff0 & ~(1<<fls(diff0))) == 0)
+	/* equal to "(diff0 & ~(1 << __ffs(diff0)))" */
+	if ((diff0 & (diff0 - 1)) == 0)
 		return 1;
 
 	return -1;
-- 
2.11.0