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Commit 2a23aa1d authored by Jonathan Brassow's avatar Jonathan Brassow Committed by Alasdair G Kergon
Browse files

dm log: make module use tracking internal 



Remove internal module reference fields from the interface.

Signed-off-by: default avatarJonathan Brassow <jbrassow@redhat.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
parent b8206bc3

drivers/md/dm-log.c

+94 −29
Original line number Diff line number Diff line
@@ -16,34 +16,51 @@ 


#define DM_MSG_PREFIX "dirty region log"



struct dm_dirty_log_internal {

	struct dm_dirty_log_type *type;



	struct list_head list;

	long use;

};



static LIST_HEAD(_log_types);

static DEFINE_SPINLOCK(_lock);



static struct dm_dirty_log_type *_get_type(const char *type_name)

static struct dm_dirty_log_internal *__find_dirty_log_type(const char *name)

{

	struct dm_dirty_log_type *type;

	struct dm_dirty_log_internal *log_type;



	list_for_each_entry(log_type, &_log_types, list)

		if (!strcmp(name, log_type->type->name))

			return log_type;



	spin_lock(&_lock);

	list_for_each_entry (type, &_log_types, list)

		if (!strcmp(type_name, type->name)) {

			if (!type->use_count && !try_module_get(type->module)){

				spin_unlock(&_lock);

	return NULL;

}

			type->use_count++;

			spin_unlock(&_lock);

			return type;



static struct dm_dirty_log_internal *_get_dirty_log_type(const char *name)

{

	struct dm_dirty_log_internal *log_type;



	spin_lock(&_lock);



	log_type = __find_dirty_log_type(name);

	if (log_type) {

		if (!log_type->use && !try_module_get(log_type->type->module))

			log_type = NULL;

		else

			log_type->use++;

	}



	spin_unlock(&_lock);

	return NULL;



	return log_type;

}



/*

 * get_type

 * @type_name

 *

 * Attempt to retrieve the dirty_log_type by name.  If not already

 * Attempt to retrieve the dm_dirty_log_type by name.  If not already

 * available, attempt to load the appropriate module.

 *

 * Log modules are named "dm-log-" followed by the 'type_name'.
@@ -59,11 +76,14 @@ static struct dm_dirty_log_type *_get_type(const char *type_name) 
static struct dm_dirty_log_type *get_type(const char *type_name)

{

	char *p, *type_name_dup;

	struct dm_dirty_log_type *type;

	struct dm_dirty_log_internal *log_type;



	if (!type_name)

		return NULL;



	type = _get_type(type_name);

	if (type)

		return type;

	log_type = _get_dirty_log_type(type_name);

	if (log_type)

		return log_type->type;



	type_name_dup = kstrdup(type_name, GFP_KERNEL);

	if (!type_name_dup) {
@@ -73,50 +93,95 @@ static struct dm_dirty_log_type *get_type(const char *type_name) 
	}



	while (request_module("dm-log-%s", type_name_dup) ||

	       !(type = _get_type(type_name))) {

	       !(log_type = _get_dirty_log_type(type_name))) {

		p = strrchr(type_name_dup, '-');

		if (!p)

			break;

		p[0] = '\0';

	}



	if (!type)

	if (!log_type)

		DMWARN("Module for logging type \"%s\" not found.", type_name);



	kfree(type_name_dup);



	return type;

	return log_type ? log_type->type : NULL;

}



static void put_type(struct dm_dirty_log_type *type)

{

	struct dm_dirty_log_internal *log_type;



	if (!type)

		return;



	spin_lock(&_lock);

	if (!--type->use_count)

	log_type = __find_dirty_log_type(type->name);

	if (!log_type)

		goto out;



	if (!--log_type->use)

		module_put(type->module);



	BUG_ON(log_type->use < 0);



out:

	spin_unlock(&_lock);

}



static struct dm_dirty_log_internal *_alloc_dirty_log_type(struct dm_dirty_log_type *type)

{

	struct dm_dirty_log_internal *log_type = kzalloc(sizeof(*log_type),

							 GFP_KERNEL);



	if (log_type)

		log_type->type = type;



	return log_type;

}



int dm_dirty_log_type_register(struct dm_dirty_log_type *type)

{

	struct dm_dirty_log_internal *log_type = _alloc_dirty_log_type(type);

	int r = 0;



	if (!log_type)

		return -ENOMEM;



	spin_lock(&_lock);

	type->use_count = 0;

	list_add(&type->list, &_log_types);

	if (!__find_dirty_log_type(type->name))

		list_add(&log_type->list, &_log_types);

	else {

		kfree(log_type);

		r = -EEXIST;

	}

	spin_unlock(&_lock);



	return 0;

	return r;

}

EXPORT_SYMBOL(dm_dirty_log_type_register);



int dm_dirty_log_type_unregister(struct dm_dirty_log_type *type)

{

	struct dm_dirty_log_internal *log_type;



	spin_lock(&_lock);



	if (type->use_count)

		DMWARN("Attempt to unregister a log type that is still in use");

	else

		list_del(&type->list);

	log_type = __find_dirty_log_type(type->name);

	if (!log_type) {

		spin_unlock(&_lock);

		return -EINVAL;

	}



	if (log_type->use) {

		spin_unlock(&_lock);

		return -ETXTBSY;

	}



	list_del(&log_type->list);



	spin_unlock(&_lock);

	kfree(log_type);



	return 0;

}

drivers/md/dm-log.h

+0 −2
Original line number Diff line number Diff line
@@ -25,10 +25,8 @@ struct dm_dirty_log { 
};



struct dm_dirty_log_type {

	struct list_head list;

	const char *name;

	struct module *module;

	unsigned use_count;



	int (*ctr)(struct dm_dirty_log *log, struct dm_target *ti,

		   unsigned argc, char **argv);