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Commit 45194e4f authored by Cheng Renquan's avatar Cheng Renquan Committed by Alasdair G Kergon
Browse files

dm target: remove struct tt_internal 



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;

Cc: stable@kernel.org
Signed-off-by: default avatarCheng Renquan <crquan@gmail.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
Reviewed-by: default avatarAlasdair G Kergon <agk@redhat.com>
parent 570b9d96

drivers/md/dm-target.c

+30 −60
Original line number Diff line number Diff line
@@ -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_type *t) 
 * 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;

drivers/md/dm.h

+1 −1
Original line number Diff line number Diff line
@@ -60,7 +60,7 @@ int dm_table_barrier_ok(struct dm_table *t); 
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);

include/linux/device-mapper.h

+3 −0
Original line number Diff line number Diff line
@@ -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 {