[PATCH v5 1/3] mtd: mtdpart: Make ECC stat handling consistent
Boris Brezillon
boris.brezillon at free-electrons.com
Thu Jan 11 01:06:36 PST 2018
On Tue, 9 Jan 2018 09:50:33 +0100
Boris Brezillon <boris.brezillon at free-electrons.com> wrote:
> part_read() and part_read_oob() where counting ECC failures and
> bitflips differently. Adjust part_read_oob() to mimic what is done in
> part_read(). This is in needed to use ->_read_oob() as a fallback when
> when ->_read() is not implemented.
>
> Note that bitflips and ECC failure accounting on MTD partitions is
> broken by design, because nothing prevents concurrent accesses to the
> underlying master MTD device between the moment we save the stats in a
> local variable and the moment master->_read[_oob]() returns. It's not
> something that can easily be fixed, so leave it like that for now.
Applied the series (also fixed the typo reported by Robert).
>
> Suggested-by: Brian Norris <computersforpeace at gmail.com>
> Signed-off-by: Boris Brezillon <boris.brezillon at free-electrons.com>
> Tested-by: Ladislav Michl <ladis at linux-mips.org>
> ---
> Changes in v5:
> - save master's ECC stats before calling ->_read_oob()
>
> Changes in v4:
> - new patch
> ---
> drivers/mtd/mtdpart.c | 14 ++++++++------
> 1 file changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
> index be088bccd593..79bf1f61c7a0 100644
> --- a/drivers/mtd/mtdpart.c
> +++ b/drivers/mtd/mtdpart.c
> @@ -105,6 +105,7 @@ static int part_read_oob(struct mtd_info *mtd, loff_t from,
> struct mtd_oob_ops *ops)
> {
> struct mtd_part *part = mtd_to_part(mtd);
> + struct mtd_ecc_stats stats;
> int res;
>
> if (from >= mtd->size)
> @@ -126,13 +127,14 @@ static int part_read_oob(struct mtd_info *mtd, loff_t from,
> return -EINVAL;
> }
>
> + stats = part->parent->ecc_stats;
> res = part->parent->_read_oob(part->parent, from + part->offset, ops);
> - if (unlikely(res)) {
> - if (mtd_is_bitflip(res))
> - mtd->ecc_stats.corrected++;
> - if (mtd_is_eccerr(res))
> - mtd->ecc_stats.failed++;
> - }
> + if (unlikely(mtd_is_eccerr(res)))
> + mtd->ecc_stats.failed +=
> + part->parent->ecc_stats.failed - stats.failed;
> + else
> + mtd->ecc_stats.corrected +=
> + part->parent->ecc_stats.corrected - stats.corrected;
> return res;
> }
>
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