mtd: rawnand: fix return value check for bad block status

commit e9893e6fa932f42c90c4ac5849fa9aa0f0f00a34 upstream.

Positive return value from read_oob() is making false BAD
blocks. For some of the NAND controllers, OOB bytes will be
protected with ECC and read_oob() will return number of bitflips.
If there is any bitflip in ECC protected OOB bytes for BAD block
status page, then that block is getting treated as BAD.

Fixes: c120e75e0e7d ("mtd: nand: use read_oob() instead of cmdfunc() for bad block check")
Cc: <stable@vger.kernel.org>
Signed-off-by: Abhishek Sahu <absahu@codeaurora.org>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
[backported to 4.14.y]
Signed-off-by: Abhishek Sahu <absahu@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 528e04f..d410de3 100644 (file)
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -440,7 +440,7 @@ static int nand_block_bad(struct mtd_info *mtd, loff_t ofs)
 
        for (; page < page_end; page++) {
                res = chip->ecc.read_oob(mtd, chip, page);
-               if (res)
+               if (res < 0)
                        return res;
 
                bad = chip->oob_poi[chip->badblockpos];