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@@ -16,34 +16,51 @@
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#define DM_MSG_PREFIX "dirty region log"
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+struct dm_dirty_log_internal {
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+ struct dm_dirty_log_type *type;
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+
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+ struct list_head list;
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+ long use;
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+};
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+
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static LIST_HEAD(_log_types);
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static DEFINE_SPINLOCK(_lock);
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-static struct dm_dirty_log_type *_get_type(const char *type_name)
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+static struct dm_dirty_log_internal *__find_dirty_log_type(const char *name)
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{
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- struct dm_dirty_log_type *type;
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+ struct dm_dirty_log_internal *log_type;
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+
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+ list_for_each_entry(log_type, &_log_types, list)
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+ if (!strcmp(name, log_type->type->name))
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+ return log_type;
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+
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+ return NULL;
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+}
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+
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+static struct dm_dirty_log_internal *_get_dirty_log_type(const char *name)
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+{
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+ struct dm_dirty_log_internal *log_type;
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spin_lock(&_lock);
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- list_for_each_entry (type, &_log_types, list)
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- if (!strcmp(type_name, type->name)) {
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- if (!type->use_count && !try_module_get(type->module)){
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- spin_unlock(&_lock);
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- return NULL;
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- }
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- type->use_count++;
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- spin_unlock(&_lock);
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- return type;
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- }
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+
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+ log_type = __find_dirty_log_type(name);
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+ if (log_type) {
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+ if (!log_type->use && !try_module_get(log_type->type->module))
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+ log_type = NULL;
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+ else
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+ log_type->use++;
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+ }
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spin_unlock(&_lock);
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- return NULL;
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+
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+ return log_type;
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}
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/*
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* get_type
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* @type_name
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*
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- * Attempt to retrieve the dirty_log_type by name. If not already
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+ * Attempt to retrieve the dm_dirty_log_type by name. If not already
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* available, attempt to load the appropriate module.
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*
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* Log modules are named "dm-log-" followed by the 'type_name'.
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@@ -59,11 +76,14 @@ static struct dm_dirty_log_type *_get_type(const char *type_name)
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static struct dm_dirty_log_type *get_type(const char *type_name)
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{
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char *p, *type_name_dup;
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- struct dm_dirty_log_type *type;
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+ struct dm_dirty_log_internal *log_type;
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- type = _get_type(type_name);
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- if (type)
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- return type;
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+ if (!type_name)
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+ return NULL;
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+
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+ log_type = _get_dirty_log_type(type_name);
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+ if (log_type)
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+ return log_type->type;
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type_name_dup = kstrdup(type_name, GFP_KERNEL);
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if (!type_name_dup) {
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@@ -73,50 +93,95 @@ static struct dm_dirty_log_type *get_type(const char *type_name)
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}
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while (request_module("dm-log-%s", type_name_dup) ||
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- !(type = _get_type(type_name))) {
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+ !(log_type = _get_dirty_log_type(type_name))) {
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p = strrchr(type_name_dup, '-');
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if (!p)
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break;
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p[0] = '\0';
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}
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- if (!type)
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+ if (!log_type)
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DMWARN("Module for logging type \"%s\" not found.", type_name);
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kfree(type_name_dup);
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- return type;
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+ return log_type ? log_type->type : NULL;
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}
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static void put_type(struct dm_dirty_log_type *type)
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{
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+ struct dm_dirty_log_internal *log_type;
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+
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+ if (!type)
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+ return;
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+
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spin_lock(&_lock);
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- if (!--type->use_count)
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+ log_type = __find_dirty_log_type(type->name);
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+ if (!log_type)
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+ goto out;
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+
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+ if (!--log_type->use)
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module_put(type->module);
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+
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+ BUG_ON(log_type->use < 0);
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+
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+out:
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spin_unlock(&_lock);
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}
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+static struct dm_dirty_log_internal *_alloc_dirty_log_type(struct dm_dirty_log_type *type)
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+{
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+ struct dm_dirty_log_internal *log_type = kzalloc(sizeof(*log_type),
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+ GFP_KERNEL);
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+
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+ if (log_type)
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+ log_type->type = type;
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+
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+ return log_type;
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+}
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+
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int dm_dirty_log_type_register(struct dm_dirty_log_type *type)
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{
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+ struct dm_dirty_log_internal *log_type = _alloc_dirty_log_type(type);
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+ int r = 0;
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+
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+ if (!log_type)
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+ return -ENOMEM;
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+
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spin_lock(&_lock);
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- type->use_count = 0;
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- list_add(&type->list, &_log_types);
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+ if (!__find_dirty_log_type(type->name))
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+ list_add(&log_type->list, &_log_types);
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+ else {
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+ kfree(log_type);
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+ r = -EEXIST;
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+ }
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spin_unlock(&_lock);
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- return 0;
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+ return r;
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}
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EXPORT_SYMBOL(dm_dirty_log_type_register);
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int dm_dirty_log_type_unregister(struct dm_dirty_log_type *type)
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{
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+ struct dm_dirty_log_internal *log_type;
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+
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spin_lock(&_lock);
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- if (type->use_count)
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- DMWARN("Attempt to unregister a log type that is still in use");
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- else
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- list_del(&type->list);
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+ log_type = __find_dirty_log_type(type->name);
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+ if (!log_type) {
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+ spin_unlock(&_lock);
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+ return -EINVAL;
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+ }
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+
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+ if (log_type->use) {
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+ spin_unlock(&_lock);
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+ return -ETXTBSY;
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+ }
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+
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+ list_del(&log_type->list);
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spin_unlock(&_lock);
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+ kfree(log_type);
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return 0;
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}
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