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- From e237285113963bd1dd2e925770aa8b3aa8a1894c Mon Sep 17 00:00:00 2001
- From: =?UTF-8?q?Micha=C5=82=20K=C4=99pie=C5=84?= <[email protected]>
- Date: Wed, 29 Jun 2022 14:57:34 +0200
- Subject: [PATCH 1/4] mtd: track maximum number of bitflips for each read
- request
- MIME-Version: 1.0
- Content-Type: text/plain; charset=UTF-8
- Content-Transfer-Encoding: 8bit
- 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 <[email protected]>
- Signed-off-by: Michał Kępień <[email protected]>
- Signed-off-by: Miquel Raynal <[email protected]>
- Link: https://lore.kernel.org/linux-mtd/[email protected]
- ---
- drivers/mtd/mtdcore.c | 5 +++++
- include/linux/mtd/mtd.h | 5 +++++
- 2 files changed, 10 insertions(+)
- --- a/drivers/mtd/mtdcore.c
- +++ b/drivers/mtd/mtdcore.c
- @@ -1676,6 +1676,9 @@ int mtd_read_oob(struct mtd_info *mtd, l
- 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
- @@ -1693,6 +1696,8 @@ int mtd_read_oob(struct mtd_info *mtd, l
- 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);
- --- a/include/linux/mtd/mtd.h
- +++ b/include/linux/mtd/mtd.h
- @@ -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;
- };
-
- #define MTD_MAX_OOBFREE_ENTRIES_LARGE 32
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