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Commit adc83bf8 authored by Brian Norris's avatar Brian Norris
Browse files

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: default avatarBrian Norris <computersforpeace@gmail.com>
Reviewed-by: default avatarBoris Brezillon <boris.brezillon@free-electrons.com>
parent 07fd2f87

drivers/mtd/mtdcore.c

+1 −2
Original line number Diff line number Diff line
@@ -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);

drivers/mtd/mtdcore.h

+2 −0
Original line number Diff line number Diff line
@@ -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);

drivers/mtd/mtdpart.c

+33 −2
Original line number Diff line number Diff line
@@ -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;

include/linux/mtd/partitions.h

+1 −0
Original line number Diff line number Diff line
@@ -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 */