Re: [PATCH 3/4] mtd: Introduce mtd_block_isreserved()

Brian Norris
2014-05-13T01:32:01Z

On Fri, Mar 21, 2014 at 08:57:43AM -0300, Ezequiel Garcia wrote:
> In addition to mtd_block_isbad(), which checks if a block is bad or reserved,
> it's needed to check if a block is reserved only (but not bad). This commit
> adds an MTD interface for it, in a similar fashion to mtd_block_isbad().
>
> Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
> ---
> drivers/mtd/mtdcore.c | 10 ++++++++++
> drivers/mtd/mtdpart.c | 9 +++++++++
> drivers/mtd/nand/nand_base.c | 1 +
> drivers/mtd/nand/nand_bbt.c | 14 ++++++++++++++
> include/linux/mtd/mtd.h | 2 ++
> include/linux/mtd/nand.h | 1 +
> 6 files changed, 37 insertions(+)
>
> diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
> index c5e9943..d65c5dc 100644
> --- a/drivers/mtd/mtdcore.c
> +++ b/drivers/mtd/mtdcore.c
> @@ -1012,6 +1012,16 @@ int mtd_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
> }
> EXPORT_SYMBOL_GPL(mtd_is_locked);
>
> +int mtd_block_isreserved(struct mtd_info *mtd, loff_t ofs)
> +{
> + if (!mtd->_block_isreserved)
> + return 0;
> + if (ofs < 0 || ofs > mtd->size)
> + return -EINVAL;

At first, I was going to recommend that the out-of-bounds check go
before the !mtd->_block_isreserved check, since it's best to warn users
for invalid input. But then, mtd_block_isbad() has the same ordering, so
it'd be nice to consistent...

Do we flip a coin to decide whether to change both or leave as-is? :)

> + return mtd->_block_isreserved(mtd, ofs);
> +}
> +EXPORT_SYMBOL_GPL(mtd_block_isreserved);
> +
> int mtd_block_isbad(struct mtd_info *mtd, loff_t ofs)
> {
> if (!mtd->_block_isbad)
> diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c
> index 1ca9aec..921e8c6 100644
> --- a/drivers/mtd/mtdpart.c
> +++ b/drivers/mtd/mtdpart.c
> @@ -290,6 +290,13 @@ static void part_resume(struct mtd_info *mtd)
> part->master->_resume(part->master);
> }
>
> +static int part_block_isreserved(struct mtd_info *mtd, loff_t ofs)
> +{
> + struct mtd_part *part = PART(mtd);
> + ofs += part->offset;
> + return part->master->_block_isreserved(part->master, ofs);
> +}
> +
> static int part_block_isbad(struct mtd_info *mtd, loff_t ofs)
> {
> struct mtd_part *part = PART(mtd);
> @@ -422,6 +429,8 @@ static struct mtd_part *allocate_partition(struct mtd_info *master,
> slave->mtd._unlock = part_unlock;
> if (master->_is_locked)
> slave->mtd._is_locked = part_is_locked;
> + if (master->_block_isreserved)
> + slave->mtd._block_isreserved = part_block_isreserved;
> if (master->_block_isbad)
> slave->mtd._block_isbad = part_block_isbad;
> if (master->_block_markbad)
> diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
> index 5826da3..58f5884 100644
> --- a/drivers/mtd/nand/nand_base.c
> +++ b/drivers/mtd/nand/nand_base.c
> @@ -4044,6 +4044,7 @@ int nand_scan_tail(struct mtd_info *mtd)
> mtd->_unlock = NULL;
> mtd->_suspend = nand_suspend;
> mtd->_resume = nand_resume;
> + mtd->_block_isreserved = nand_isreserved_bbt;

I think you want a small wrapper function in case we aren't using a BBT
at all. See nand_block_checkbad(), which checks for !chip->bbt. So we'd
need:

if (!chip->bbt)
return 0;

> mtd->_block_isbad = nand_block_isbad;
> mtd->_block_markbad = nand_block_markbad;
> mtd->writebufsize = mtd->writesize;
> diff --git a/drivers/mtd/nand/nand_bbt.c b/drivers/mtd/nand/nand_bbt.c
> index ea9a266..fd21169 100644
> --- a/drivers/mtd/nand/nand_bbt.c
> +++ b/drivers/mtd/nand/nand_bbt.c
> @@ -1312,6 +1312,20 @@ int nand_default_bbt(struct mtd_info *mtd)
> }
>
> /**
> + * nand_isreserved_bbt - [NAND Interface] Check if a block is reserved
> + * @mtd: MTD device structure
> + * @offs: offset in the device
> + */
> +int nand_isreserved_bbt(struct mtd_info *mtd, loff_t offs)
> +{
> + struct nand_chip *this = mtd->priv;
> + int block;
> +
> + block = (int)(offs >> this->bbt_erase_shift);
> + return bbt_get_entry(this, block) == BBT_BLOCK_RESERVED;
> +}
> +
> +/**
> * nand_isbad_bbt - [NAND Interface] Check if a block is bad
> * @mtd: MTD device structure
> * @offs: offset in the device
> diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
> index a1b0b4c..031ff3a 100644
> --- a/include/linux/mtd/mtd.h
> +++ b/include/linux/mtd/mtd.h
> @@ -222,6 +222,7 @@ struct mtd_info {
> int (*_lock) (struct mtd_info *mtd, loff_t ofs, uint64_t len);
> int (*_unlock) (struct mtd_info *mtd, loff_t ofs, uint64_t len);
> int (*_is_locked) (struct mtd_info *mtd, loff_t ofs, uint64_t len);
> + 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 (*_suspend) (struct mtd_info *mtd);
> @@ -302,6 +303,7 @@ static inline void mtd_sync(struct mtd_info *mtd)
> int mtd_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len);
> int mtd_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len);
> int mtd_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len);
> +int mtd_block_isreserved(struct mtd_info *mtd, loff_t ofs);
> int mtd_block_isbad(struct mtd_info *mtd, loff_t ofs);
> int mtd_block_markbad(struct mtd_info *mtd, loff_t ofs);
>
> diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
> index 0747fef..3b78c6b 100644
> --- a/include/linux/mtd/nand.h
> +++ b/include/linux/mtd/nand.h
> @@ -806,6 +806,7 @@ extern struct nand_manufacturers nand_manuf_ids[];
> extern int nand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd);
> extern int nand_default_bbt(struct mtd_info *mtd);
> extern int nand_markbad_bbt(struct mtd_info *mtd, loff_t offs);
> +extern int nand_isreserved_bbt(struct mtd_info *mtd, loff_t offs);
> extern int nand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt);
> extern int nand_erase_nand(struct mtd_info *mtd, struct erase_info *instr,
> int allowbbt);

Otherwise, looks good.

Brian