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 <computersforpeace@gmail.com>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
This commit is contained in:
Brian Norris 2015-12-09 10:24:03 -08:00
parent 07fd2f871c
commit adc83bf889
4 changed files with 37 additions and 4 deletions

View File

@ -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);

View File

@ -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);

View File

@ -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;

View File

@ -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 */