diff options
| -rw-r--r-- | drivers/md/dm-log.c | 123 | ||||
| -rw-r--r-- | drivers/md/dm-log.h | 2 |
2 files changed, 94 insertions, 31 deletions
diff --git a/drivers/md/dm-log.c b/drivers/md/dm-log.c index 82df73f67a0..e6b6a9d5fdd 100644 --- a/drivers/md/dm-log.c +++ b/drivers/md/dm-log.c @@ -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; + + return NULL; +} + +static struct dm_dirty_log_internal *_get_dirty_log_type(const char *name) +{ + struct dm_dirty_log_internal *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; - } + + 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; - type = _get_type(type_name); - if (type) - return type; + if (!type_name) + return NULL; + + 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; } diff --git a/drivers/md/dm-log.h b/drivers/md/dm-log.h index 2da48a857cb..600c5fb2daa 100644 --- a/drivers/md/dm-log.h +++ b/drivers/md/dm-log.h @@ -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); |