[PATCH 4.17 102/220] mtd: rawnand: fix return value check for bad block status

[Greg Kroah-Hartman]

4.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Abhishek Sahu <absahu@xxxxxxxxxxxxxx>

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@xxxxxxxxxxxxxxx>
Signed-off-by: Abhishek Sahu <absahu@xxxxxxxxxxxxxx>
Reviewed-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/mtd/nand/raw/nand_base.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/mtd/nand/raw/nand_base.c
+++ b/drivers/mtd/nand/raw/nand_base.c
@@ -440,7 +440,7 @@ static int nand_block_bad(struct mtd_inf
 
 	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];