dm log: remove struct dm_dirty_log_internal

Remove the 'dm_dirty_log_internal' structure.  The resulting cleanup
eliminates extra memory allocations.  Therefore exposing the internal
list_head to the external 'dm_dirty_log_type' structure is a worthwhile
compromise.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

diff --git a/drivers/md/dm-log.c b/drivers/md/dm-log.c
index 094c8f0..be233bc 100644 (file)
--- a/drivers/md/dm-log.c
+++ b/drivers/md/dm-log.c
@@ -16,34 +16,28 @@
 
 #define DM_MSG_PREFIX "dirty region log"
 
-struct dm_dirty_log_internal {
-       struct dm_dirty_log_type *type;
-
-       struct list_head list;
-};
-
 static LIST_HEAD(_log_types);
 static DEFINE_SPINLOCK(_lock);
 
-static struct dm_dirty_log_internal *__find_dirty_log_type(const char *name)
+static struct dm_dirty_log_type *__find_dirty_log_type(const char *name)
 {
-       struct dm_dirty_log_internal *log_type;
+       struct dm_dirty_log_type *log_type;
 
        list_for_each_entry(log_type, &_log_types, list)
-               if (!strcmp(name, log_type->type->name))
+               if (!strcmp(name, log_type->name))
                        return log_type;
 
        return NULL;
 }
 
-static struct dm_dirty_log_internal *_get_dirty_log_type(const char *name)
+static struct dm_dirty_log_type *_get_dirty_log_type(const char *name)
 {
-       struct dm_dirty_log_internal *log_type;
+       struct dm_dirty_log_type *log_type;
 
        spin_lock(&_lock);
 
        log_type = __find_dirty_log_type(name);
-       if (log_type && !try_module_get(log_type->type->module))
+       if (log_type && !try_module_get(log_type->module))
                log_type = NULL;
 
        spin_unlock(&_lock);
@@ -71,14 +65,14 @@ static struct dm_dirty_log_internal *_get_dirty_log_type(const char *name)
 static struct dm_dirty_log_type *get_type(const char *type_name)
 {
        char *p, *type_name_dup;
-       struct dm_dirty_log_internal *log_type;
+       struct dm_dirty_log_type *log_type;
 
        if (!type_name)
                return NULL;
 
        log_type = _get_dirty_log_type(type_name);
        if (log_type)
-               return log_type->type;
+               return log_type;
 
        type_name_dup = kstrdup(type_name, GFP_KERNEL);
        if (!type_name_dup) {
@@ -100,19 +94,16 @@ static struct dm_dirty_log_type *get_type(const char *type_name)
 
        kfree(type_name_dup);
 
-       return log_type ? log_type->type : NULL;
+       return log_type;
 }
 
 static void put_type(struct dm_dirty_log_type *type)
 {
-       struct dm_dirty_log_internal *log_type;
-
        if (!type)
                return;
 
        spin_lock(&_lock);
-       log_type = __find_dirty_log_type(type->name);
-       if (!log_type)
+       if (!__find_dirty_log_type(type->name))
                goto out;
 
        module_put(type->module);
@@ -121,32 +112,15 @@ 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);
        if (!__find_dirty_log_type(type->name))
-               list_add(&log_type->list, &_log_types);
-       else {
-               kfree(log_type);
+               list_add(&type->list, &_log_types);
+       else
                r = -EEXIST;
-       }
        spin_unlock(&_lock);
 
        return r;
@@ -155,20 +129,16 @@ 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);
 
-       log_type = __find_dirty_log_type(type->name);
-       if (!log_type) {
+       if (!__find_dirty_log_type(type->name)) {
                spin_unlock(&_lock);
                return -EINVAL;
        }
 
-       list_del(&log_type->list);
+       list_del(&type->list);
 
        spin_unlock(&_lock);
-       kfree(log_type);
 
        return 0;
 }

diff --git a/include/linux/dm-dirty-log.h b/include/linux/dm-dirty-log.h
index 600c5fb..727602b 100644 (file)
--- a/include/linux/dm-dirty-log.h
+++ b/include/linux/dm-dirty-log.h
@@ -28,6 +28,9 @@ struct dm_dirty_log_type {
        const char *name;
        struct module *module;
 
+       /* For internal device-mapper use */
+       struct list_head list;
+
        int (*ctr)(struct dm_dirty_log *log, struct dm_target *ti,
                   unsigned argc, char **argv);
        void (*dtr)(struct dm_dirty_log *log);