From ea3b2ea24ef0f2ef9c6795b19cff456195b6728a Mon Sep 17 00:00:00 2001 From: Shmulik Ladkani Date: Fri, 8 Jun 2012 18:29:06 +0300 Subject: [PATCH] mtd: nand: initialize bitflip_threshold prior to BBT scanning As of edbc454 [mtd: driver _read() returns max_bitflips; mtd_read() returns -EUCLEAN], 'mtd->bitflip_threshold' must be set for mtd devices having ECC, prior any 'mtd_read()' call. Otherwise, 'mtd_read()' will falsely return -EUCLEAN. Normally, 'mtd->bitflip_threshold' is initialized when the MTD is added. However, this is too late for NAND MTDs, as 'scan_bbt()' is invoked prior the existing initialization of 'mtd->bitflip_threshold'. This is a problem since 'scan_bbt()' calls 'mtd_read()', in the case of a flash-based bad block table. It resulted in a falsely reported bitflips indication during BBT read, which lead to constant scrubbing of the flash BBT blocks. Initialize 'mtd->bitflip_threshold' to its default value (if not already set by the driver), prior to invocation of 'scan_bbt()'. Reported-by: Sascha Hauer Tested-by: Sascha Hauer Signed-off-by: Shmulik Ladkani Signed-off-by: Artem Bityutskiy Signed-off-by: David Woodhouse --- drivers/mtd/nand/nand_base.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index d47586cf64ce..a11253a0fcab 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -3501,6 +3501,13 @@ int nand_scan_tail(struct mtd_info *mtd) /* propagate ecc info to mtd_info */ mtd->ecclayout = chip->ecc.layout; mtd->ecc_strength = chip->ecc.strength; + /* + * Initialize bitflip_threshold to its default prior scan_bbt() call. + * scan_bbt() might invoke mtd_read(), thus bitflip_threshold must be + * properly set. + */ + if (!mtd->bitflip_threshold) + mtd->bitflip_threshold = mtd->ecc_strength; /* Check, if we should skip the bad block table scan */ if (chip->options & NAND_SKIP_BBTSCAN) -- 2.20.1