From adc83bf8896353603213754353dd66dae69e3d7f Mon Sep 17 00:00:00 2001 From: Brian Norris Date: Wed, 9 Dec 2015 10:24:03 -0800 Subject: [PATCH] mtd: partitions: support a cleanup callback for parsers If partition parsers need to clean up their resources, we shouldn't assume that all memory will fit in a single kmalloc() that the caller can kfree(). We should allow the parser to provide a proper cleanup routine. Note that this means we need to keep a hold on the parser's module for a bit longer, and release it later with mtd_part_parser_put(). Alongside this, define a default callback that we'll automatically use if the parser doesn't provide one, so we can still retain the old behavior. Signed-off-by: Brian Norris Reviewed-by: Boris Brezillon --- drivers/mtd/mtdcore.c | 3 +-- drivers/mtd/mtdcore.h | 2 ++ drivers/mtd/mtdpart.c | 35 ++++++++++++++++++++++++++++++++-- include/linux/mtd/partitions.h | 1 + 4 files changed, 37 insertions(+), 4 deletions(-) diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c index 20b2b38247b6..89d811e7b04a 100644 --- a/drivers/mtd/mtdcore.c +++ b/drivers/mtd/mtdcore.c @@ -630,8 +630,7 @@ int mtd_device_parse_register(struct mtd_info *mtd, const char * const *types, out: /* Cleanup any parsed partitions */ - if (parsed.parser) - kfree(parsed.parts); + mtd_part_parser_cleanup(&parsed); return ret; } EXPORT_SYMBOL_GPL(mtd_device_parse_register); diff --git a/drivers/mtd/mtdcore.h b/drivers/mtd/mtdcore.h index ce81cc2002f4..55fdb8e1fd2a 100644 --- a/drivers/mtd/mtdcore.h +++ b/drivers/mtd/mtdcore.h @@ -17,6 +17,8 @@ int parse_mtd_partitions(struct mtd_info *master, const char * const *types, struct mtd_partitions *pparts, struct mtd_part_parser_data *data); +void mtd_part_parser_cleanup(struct mtd_partitions *parts); + int __init init_mtdchar(void); void __exit cleanup_mtdchar(void); diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c index 53517d7653cb..10bf304027dd 100644 --- a/drivers/mtd/mtdpart.c +++ b/drivers/mtd/mtdpart.c @@ -709,10 +709,23 @@ static inline void mtd_part_parser_put(const struct mtd_part_parser *p) module_put(p->owner); } +/* + * Many partition parsers just expected the core to kfree() all their data in + * one chunk. Do that by default. + */ +static void mtd_part_parser_cleanup_default(const struct mtd_partition *pparts, + int nr_parts) +{ + kfree(pparts); +} + int __register_mtd_parser(struct mtd_part_parser *p, struct module *owner) { p->owner = owner; + if (!p->cleanup) + p->cleanup = &mtd_part_parser_cleanup_default; + spin_lock(&part_parser_lock); list_add(&p->list, &part_parsers); spin_unlock(&part_parser_lock); @@ -756,7 +769,9 @@ static const char * const default_mtd_part_types[] = { * This function may return: * o a negative error code in case of failure * o zero otherwise, and @pparts will describe the partitions, number of - * partitions, and the parser which parsed them + * partitions, and the parser which parsed them. Caller must release + * resources with mtd_part_parser_cleanup() when finished with the returned + * data. */ int parse_mtd_partitions(struct mtd_info *master, const char *const *types, struct mtd_partitions *pparts, @@ -780,7 +795,6 @@ int parse_mtd_partitions(struct mtd_info *master, const char *const *types, ret = (*parser->parse_fn)(master, &pparts->parts, data); pr_debug("%s: parser %s: %i\n", master->name, parser->name, ret); - mtd_part_parser_put(parser); if (ret > 0) { printk(KERN_NOTICE "%d %s partitions found on MTD device %s\n", ret, parser->name, master->name); @@ -788,6 +802,7 @@ int parse_mtd_partitions(struct mtd_info *master, const char *const *types, pparts->parser = parser; return 0; } + mtd_part_parser_put(parser); /* * Stash the first error we see; only report it if no parser * succeeds @@ -798,6 +813,22 @@ int parse_mtd_partitions(struct mtd_info *master, const char *const *types, return err; } +void mtd_part_parser_cleanup(struct mtd_partitions *parts) +{ + const struct mtd_part_parser *parser; + + if (!parts) + return; + + parser = parts->parser; + if (parser) { + if (parser->cleanup) + parser->cleanup(parts->parts, parts->nr_parts); + + mtd_part_parser_put(parser); + } +} + int mtd_is_partition(const struct mtd_info *mtd) { struct mtd_part *part; diff --git a/include/linux/mtd/partitions.h b/include/linux/mtd/partitions.h index cceaf7bd1537..70736e1e6c8f 100644 --- a/include/linux/mtd/partitions.h +++ b/include/linux/mtd/partitions.h @@ -71,6 +71,7 @@ struct mtd_part_parser { const char *name; int (*parse_fn)(struct mtd_info *, const struct mtd_partition **, struct mtd_part_parser_data *); + void (*cleanup)(const struct mtd_partition *pparts, int nr_parts); }; /* Container for passing around a set of parsed partitions */