From: Cheng Renquan <crquan@xxxxxxxxx>
The tt_internal is really just a list_head to manage registered target_type
in a double linked list,
Here embed the list_head into target_type directly,
1. to avoid kmalloc/kfree;
2. then tt_internal is really unneeded;
Signed-off-by: Cheng Renquan <crquan@xxxxxxxxx>
Signed-off-by: Alasdair G Kergon <agk@xxxxxxxxxx>
Reviewed-by: Alasdair G Kergon <agk@xxxxxxxxxx>
---
drivers/md/dm-target.c | 90 ++++++++++++++----------------------------
drivers/md/dm.h | 2
include/linux/device-mapper.h | 3 +
3 files changed, 34 insertions(+), 61 deletions(-)
Index: linux-2.6.28/drivers/md/dm-target.c
===================================================================
--- linux-2.6.28.orig/drivers/md/dm-target.c 2009-01-07 20:30:57.000000000 +0000
+++ linux-2.6.28/drivers/md/dm-target.c 2009-01-07 20:35:22.000000000 +0000
@@ -14,40 +14,34 @@
#define DM_MSG_PREFIX "target"
-struct tt_internal {
- struct target_type tt;
-
- struct list_head list;
-};
-
static LIST_HEAD(_targets);
static DECLARE_RWSEM(_lock);
#define DM_MOD_NAME_SIZE 32
-static inline struct tt_internal *__find_target_type(const char *name)
+static inline struct target_type *__find_target_type(const char *name)
{
- struct tt_internal *ti;
+ struct target_type *tt;
- list_for_each_entry (ti, &_targets, list)
- if (!strcmp(name, ti->tt.name))
- return ti;
+ list_for_each_entry(tt, &_targets, list)
+ if (!strcmp(name, tt->name))
+ return tt;
return NULL;
}
-static struct tt_internal *get_target_type(const char *name)
+static struct target_type *get_target_type(const char *name)
{
- struct tt_internal *ti;
+ struct target_type *tt;
down_read(&_lock);
- ti = __find_target_type(name);
- if (ti && !try_module_get(ti->tt.module))
- ti = NULL;
+ tt = __find_target_type(name);
+ if (tt && !try_module_get(tt->module))
+ tt = NULL;
up_read(&_lock);
- return ti;
+ return tt;
}
static void load_module(const char *name)
@@ -57,83 +51,59 @@ static void load_module(const char *name
struct target_type *dm_get_target_type(const char *name)
{
- struct tt_internal *ti = get_target_type(name);
+ struct target_type *tt = get_target_type(name);
- if (!ti) {
+ if (!tt) {
load_module(name);
- ti = get_target_type(name);
+ tt = get_target_type(name);
}
- return ti ? &ti->tt : NULL;
+ return tt;
}
-void dm_put_target_type(struct target_type *t)
+void dm_put_target_type(struct target_type *tt)
{
- struct tt_internal *ti = (struct tt_internal *) t;
-
down_read(&_lock);
- module_put(ti->tt.module);
+ module_put(tt->module);
up_read(&_lock);
-
- return;
}
-static struct tt_internal *alloc_target(struct target_type *t)
-{
- struct tt_internal *ti = kzalloc(sizeof(*ti), GFP_KERNEL);
-
- if (ti)
- ti->tt = *t;
-
- return ti;
-}
-
-
int dm_target_iterate(void (*iter_func)(struct target_type *tt,
void *param), void *param)
{
- struct tt_internal *ti;
+ struct target_type *tt;
down_read(&_lock);
- list_for_each_entry (ti, &_targets, list)
- iter_func(&ti->tt, param);
+ list_for_each_entry(tt, &_targets, list)
+ iter_func(tt, param);
up_read(&_lock);
return 0;
}
-int dm_register_target(struct target_type *t)
+int dm_register_target(struct target_type *tt)
{
int rv = 0;
- struct tt_internal *ti = alloc_target(t);
-
- if (!ti)
- return -ENOMEM;
down_write(&_lock);
- if (__find_target_type(t->name))
+ if (__find_target_type(tt->name))
rv = -EEXIST;
else
- list_add(&ti->list, &_targets);
+ list_add(&tt->list, &_targets);
up_write(&_lock);
- if (rv)
- kfree(ti);
return rv;
}
-void dm_unregister_target(struct target_type *t)
+void dm_unregister_target(struct target_type *tt)
{
- struct tt_internal *ti;
-
down_write(&_lock);
- if (!(ti = __find_target_type(t->name))) {
- DMCRIT("Unregistering unrecognised target: %s", t->name);
+ if (!__find_target_type(tt->name)) {
+ DMCRIT("Unregistering unrecognised target: %s", tt->name);
BUG();
}
- list_del(&ti->list);
- kfree(ti);
+ list_del(&tt->list);
up_write(&_lock);
}
@@ -142,17 +112,17 @@ void dm_unregister_target(struct target_
* io-err: always fails an io, useful for bringing
* up LVs that have holes in them.
*/
-static int io_err_ctr(struct dm_target *ti, unsigned int argc, char **args)
+static int io_err_ctr(struct dm_target *tt, unsigned int argc, char **args)
{
return 0;
}
-static void io_err_dtr(struct dm_target *ti)
+static void io_err_dtr(struct dm_target *tt)
{
/* empty */
}
-static int io_err_map(struct dm_target *ti, struct bio *bio,
+static int io_err_map(struct dm_target *tt, struct bio *bio,
union map_info *map_context)
{
return -EIO;
Index: linux-2.6.28/drivers/md/dm.h
===================================================================
--- linux-2.6.28.orig/drivers/md/dm.h 2009-01-07 20:19:02.000000000 +0000
+++ linux-2.6.28/drivers/md/dm.h 2009-01-07 20:32:48.000000000 +0000
@@ -60,7 +60,7 @@ int dm_table_barrier_ok(struct dm_table
int dm_target_init(void);
void dm_target_exit(void);
struct target_type *dm_get_target_type(const char *name);
-void dm_put_target_type(struct target_type *t);
+void dm_put_target_type(struct target_type *tt);
int dm_target_iterate(void (*iter_func)(struct target_type *tt,
void *param), void *param);
Index: linux-2.6.28/include/linux/device-mapper.h
===================================================================
--- linux-2.6.28.orig/include/linux/device-mapper.h 2009-01-07 20:19:02.000000000 +0000
+++ linux-2.6.28/include/linux/device-mapper.h 2009-01-07 20:32:48.000000000 +0000
@@ -139,6 +139,9 @@ struct target_type {
dm_ioctl_fn ioctl;
dm_merge_fn merge;
dm_busy_fn busy;
+
+ /* For internal device-mapper use. */
+ struct list_head list;
};
struct io_restrictions {
--
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