mtd: nand: omap: fix BCHx ecc.correct to return detected bit-flips in erased-page

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=f306e8c3b667632952f1a4a74ffb910bbc06255f
Commit:     f306e8c3b667632952f1a4a74ffb910bbc06255f
Parent:     9ab86995ed07f51c45ba1b549aff2bd6e46590e9
Author:     pekon gupta <pekon at ti.com>
AuthorDate: Thu Mar 20 18:49:58 2014 +0530
Committer:  Brian Norris <computersforpeace at gmail.com>
CommitDate: Tue May 20 16:32:17 2014 -0700

    mtd: nand: omap: fix BCHx ecc.correct to return detected bit-flips in erased-page
    
    fixes: commit 62116e5171e00f85a8d53f76e45b84423c89ff34
           mtd: nand: omap2: Support for hardware BCH error correction.
    
    In omap_elm_correct_data(), if bitflip_count in an erased-page is within the
    correctable limit (< ecc.strength), then it is not indicated back to the caller
    ecc->read_page().
    
    This mis-guides upper layers like MTD and UBIFS layer to assume erased-page as
    perfectly clean and use it for writing even if actual bitflip_count was
    dangerously high (bitflip_count > mtd->bitflip_threshold).
    
    This patch fixes this above issue, by returning 'stats' to caller
    ecc->read_page() under all scenarios.
    
    Reported-by: Brian Norris <computersforpeace at gmail.com>
    Signed-off-by: Pekon Gupta <pekon at ti.com>
    Cc: <stable at vger.kernel.org> # 3.9.x+
    Signed-off-by: Brian Norris <computersforpeace at gmail.com>
---
 drivers/mtd/nand/omap2.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index 1b800bc..10c319e 100644
--- a/drivers/mtd/nand/omap2.c
+++ b/drivers/mtd/nand/omap2.c
@@ -1382,7 +1382,7 @@ static int omap_elm_correct_data(struct mtd_info *mtd, u_char *data,
 
 	/* Check if any error reported */
 	if (!is_error_reported)
-		return 0;
+		return stat;
 
 	/* Decode BCH error using ELM module */
 	elm_decode_bch_error_page(info->elm_dev, ecc_vec, err_vec);