mtd: nand: s3c2410: fix bug in s3c2410_nand_correct_data()

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=03a97550941d17c7d5b621afde5945bbc0da6546
Commit:     03a97550941d17c7d5b621afde5945bbc0da6546
Parent:     7a654172161c8c9c7d59cbd0054d9e63c7411219
Author:     Zhaoxiu Zeng <zhaoxiu.zeng at gmail.com>
AuthorDate: Tue Apr 12 15:30:35 2016 +0800
Committer:  Boris Brezillon <boris.brezillon at free-electrons.com>
CommitDate: Tue Apr 19 22:04:53 2016 +0200

    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 at gmail.com>
    Signed-off-by: Boris Brezillon <boris.brezillon at 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 9c9397b..86ffb73 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;