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dm log: remove struct dm_dirty_log_internal
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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>
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Mike Snitzer authored and Alasdair G Kergon committed Apr 2, 2009
1 parent 84e67c9 commit ec44ab9
Showing 2 changed files with 17 additions and 44 deletions.
58 changes: 14 additions & 44 deletions drivers/md/dm-log.c
Original file line number Diff line number Diff line change
@@ -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 @@ static void put_type(struct dm_dirty_log_type *type)
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;
}
3 changes: 3 additions & 0 deletions include/linux/dm-dirty-log.h
Original file line number Diff line number Diff line change
@@ -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);

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