Hi Manivannan, Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> wrote on Sat, 30 Jan 2021 09:24:12 +0530: > The bbt pointer will be unavailable when NAND_SKIP_BBTSCAN option is > set for a NAND chip. The intention is to skip scanning for the bad > blocks during boot time. I don't have the same understanding: this flag skips the bad block table scan, not the bad block scan. We do want to scan all the devices in order to construct a RAM based table. > However, the MTD core will call > _block_isreserved() and _block_isbad() callbacks unconditionally for > the rawnand devices due to the callbacks always present while collecting > the ecc stats. > > The _block_isreserved() callback for rawnand will bail out if bbt > pointer is not available. But _block_isbad() will continue without > checking for it. So this contradicts with the NAND_SKIP_BBTSCAN option > since the bad block check will happen anyways (ie., not much difference > between scanning for bad blocks and checking each block for bad ones). > > Hence, do not check for the bad block if bbt pointer is unavailable. Not checking for bad blocks at all feels insane. I don't really get the scope and goal of such change? > > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx> > --- > drivers/mtd/nand/raw/nand_base.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c > index c33fa1b1847f..f18cd1db79a9 100644 > --- a/drivers/mtd/nand/raw/nand_base.c > +++ b/drivers/mtd/nand/raw/nand_base.c > @@ -4286,6 +4286,9 @@ static int nand_block_isbad(struct mtd_info *mtd, loff_t offs) > int chipnr = (int)(offs >> chip->chip_shift); > int ret; > > + if (!chip->bbt) > + return 0; > + > /* Select the NAND device */ > ret = nand_get_device(chip); > if (ret) Cheers, Miquèl
