[PATCH v2 6/6] mtd: partitions: support a cleanup callback for parsers
Brian Norris
computersforpeace at gmail.com
Fri Dec 4 15:25:18 PST 2015
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 at gmail.com>
---
v2:
* put more common logic in mtd_part_parser_cleanup()
* provide default cleanup routine (i.e., kfree()) for parsers
drivers/mtd/mtdcore.c | 2 +-
drivers/mtd/mtdcore.h | 2 ++
drivers/mtd/mtdpart.c | 35 +++++++++++++++++++++++++++++++++--
include/linux/mtd/partitions.h | 1 +
4 files changed, 37 insertions(+), 3 deletions(-)
diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 20b2b38247b6..466cb0da7c08 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -631,7 +631,7 @@ 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 c5108e0efe88..7ab6b313add4 100644
--- a/drivers/mtd/mtdpart.c
+++ b/drivers/mtd/mtdpart.c
@@ -706,10 +706,23 @@ 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);
@@ -753,7 +766,9 @@ 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,
@@ -777,7 +792,6 @@ 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);
@@ -785,6 +799,7 @@ 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
@@ -795,6 +810,22 @@ 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 */
--
2.6.0.rc2.230.g3dd15c0
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