Re: [RESEND PATCH v5 1/5] mtd: introduce function max_bad_blocks

From: Brian Norris
Date: Tue Nov 22 2016 - 13:49:24 EST


A few small comments.

On Mon, Nov 21, 2016 at 01:51:35PM -0600, Zach Brown wrote:
> From: Jeff Westfahl <jeff.westfahl@xxxxxx>
>
> If implemented, 'max_bad_blocks' returns the maximum number of bad
> blocks to reserve for an MTD. An implementation for NAND is coming soon.
>
> Signed-off-by: Jeff Westfahl <jeff.westfahl@xxxxxx>
> Signed-off-by: Zach Brown <zach.brown@xxxxxx>
> Acked-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxx>
> ---
> drivers/mtd/mtdpart.c | 12 ++++++++++++
> include/linux/mtd/mtd.h | 11 +++++++++++
> 2 files changed, 23 insertions(+)
>
> diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
> index fccdd49..565f0dd 100644
> --- a/drivers/mtd/mtdpart.c
> +++ b/drivers/mtd/mtdpart.c
> @@ -349,6 +349,16 @@ static const struct mtd_ooblayout_ops part_ooblayout_ops = {
> .free = part_ooblayout_free,
> };
>
> +static int part_max_bad_blocks(struct mtd_info *mtd, loff_t ofs, size_t len)
> +{
> + struct mtd_part *part = mtd_to_part(mtd);
> +
> + if ((len + ofs) > mtd->size)
> + return -EINVAL;

Normally you want the bounds checking in the top-level API, and that
should be enough for the partitions as well. Also, what about 'ofs < 0'?

> + return part->master->_max_bad_blocks(part->master,
> + ofs + part->offset, len);
> +}
> +
> static inline void free_partition(struct mtd_part *p)
> {
> kfree(p->mtd.name);
> @@ -481,6 +491,8 @@ static struct mtd_part *allocate_partition(struct mtd_info *master,
> if (master->_put_device)
> slave->mtd._put_device = part_put_device;
>
> + if (master->_max_bad_blocks)
> + slave->mtd._max_bad_blocks = part_max_bad_blocks;

Nit: add an extra blank line after? Also might make sense to stick this
up with the other bad-block-related assignments (after _block_markbad =
...).

> slave->mtd._erase = part_erase;
> slave->master = master;
> slave->offset = part->offset;
> diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
> index 13f8052..c02d3c2 100644
> --- a/include/linux/mtd/mtd.h
> +++ b/include/linux/mtd/mtd.h
> @@ -322,6 +322,7 @@ struct mtd_info {
> int (*_block_isreserved) (struct mtd_info *mtd, loff_t ofs);
> int (*_block_isbad) (struct mtd_info *mtd, loff_t ofs);
> int (*_block_markbad) (struct mtd_info *mtd, loff_t ofs);
> + int (*_max_bad_blocks) (struct mtd_info *mtd, loff_t ofs, size_t len);
> int (*_suspend) (struct mtd_info *mtd);
> void (*_resume) (struct mtd_info *mtd);
> void (*_reboot) (struct mtd_info *mtd);
> @@ -402,6 +403,16 @@ int mtd_wunit_to_pairing_info(struct mtd_info *mtd, int wunit,
> int mtd_pairing_info_to_wunit(struct mtd_info *mtd,
> const struct mtd_pairing_info *info);
> int mtd_pairing_groups(struct mtd_info *mtd);
> +
> +static inline int mtd_max_bad_blocks(struct mtd_info *mtd,
> + loff_t ofs, size_t len)
> +{

Bounds checks here?

Brian

> + if (mtd->_max_bad_blocks)
> + return mtd->_max_bad_blocks(mtd, ofs, len);
> +
> + return -ENOTSUPP;
> +}
> +
> int mtd_erase(struct mtd_info *mtd, struct erase_info *instr);
> int mtd_point(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
> void **virt, resource_size_t *phys);
> --
> 2.7.4
>