mtd: track maximum number of bitflips for each read request

mtd_read_oob() callers are currently oblivious to the details of ECC
errors detected during the read operation - they only learn (through the
return value) whether any corrected bitflips or uncorrectable errors
occurred.  More detailed ECC information can be useful to user-space
applications for making better-informed choices about moving data
around.

Extend struct mtd_oob_ops with a pointer to a newly-introduced struct
mtd_req_stats and set its 'max_bitflips' field to the maximum number of
bitflips found in a single ECC step during the read operation performed
by mtd_read_oob().  This is a prerequisite for ultimately passing that
value back to user space.

Suggested-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Michał Kępień <kernel@kempniu.pl>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220629125737.14418-2-kernel@kempniu.pl
This commit is contained in:
Michał Kępień 2022-06-29 14:57:34 +02:00 committed by Miquel Raynal
parent 9ee6718230
commit 65394169bd
2 changed files with 10 additions and 0 deletions

View File

@ -1624,6 +1624,9 @@ int mtd_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops)
if (!master->_read_oob && (!master->_read || ops->oobbuf))
return -EOPNOTSUPP;
if (ops->stats)
memset(ops->stats, 0, sizeof(*ops->stats));
if (mtd->flags & MTD_SLC_ON_MLC_EMULATION)
ret_code = mtd_io_emulated_slc(mtd, from, true, ops);
else
@ -1641,6 +1644,8 @@ int mtd_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops)
return ret_code;
if (mtd->ecc_strength == 0)
return 0; /* device lacks ecc */
if (ops->stats)
ops->stats->max_bitflips = ret_code;
return ret_code >= mtd->bitflip_threshold ? -EUCLEAN : 0;
}
EXPORT_SYMBOL_GPL(mtd_read_oob);

View File

@ -40,6 +40,10 @@ struct mtd_erase_region_info {
unsigned long *lockmap; /* If keeping bitmap of locks */
};
struct mtd_req_stats {
unsigned int max_bitflips;
};
/**
* struct mtd_oob_ops - oob operation operands
* @mode: operation mode
@ -70,6 +74,7 @@ struct mtd_oob_ops {
uint32_t ooboffs;
uint8_t *datbuf;
uint8_t *oobbuf;
struct mtd_req_stats *stats;
};
/**