Commit 952b3557 authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Alasdair G Kergon
Browse files

dm io: use slab for struct io 



Allocate "struct io" from a slab.

This patch changes dm-io, so that "struct io" is allocated from a slab cache.
It used to be allocated with kmalloc. Allocating from a slab will be needed
for the next patch, because it requires a special alignment of "struct io"
and kmalloc cannot meet this alignment.

Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
parent 542da317

drivers/md/dm-io.c

+20 −1
Original line number Diff line number Diff line
@@ -5,6 +5,8 @@ 
 * This file is released under the GPL.

 */



#include "dm.h"



#include <linux/device-mapper.h>



#include <linux/bio.h>
@@ -30,6 +32,8 @@ struct io { 
	void *context;

};



static struct kmem_cache *_dm_io_cache;



/*

 * io contexts are only dynamically allocated for asynchronous

 * io.  Since async io is likely to be the majority of io we'll
@@ -53,7 +57,7 @@ struct dm_io_client *dm_io_client_create(unsigned num_pages) 
	if (!client)

		return ERR_PTR(-ENOMEM);



	client->pool = mempool_create_kmalloc_pool(ios, sizeof(struct io));

	client->pool = mempool_create_slab_pool(ios, _dm_io_cache);

	if (!client->pool)

		goto bad;
@@ -472,3 +476,18 @@ int dm_io(struct dm_io_request *io_req, unsigned num_regions, 
			&dp, io_req->notify.fn, io_req->notify.context);

}

EXPORT_SYMBOL(dm_io);



int __init dm_io_init(void)

{

	_dm_io_cache = KMEM_CACHE(io, 0);

	if (!_dm_io_cache)

		return -ENOMEM;



	return 0;

}



void dm_io_exit(void)

{

	kmem_cache_destroy(_dm_io_cache);

	_dm_io_cache = NULL;

}

drivers/md/dm.c

+2 −0
Original line number Diff line number Diff line
@@ -275,6 +275,7 @@ static int (*_inits[])(void) __initdata = { 
	dm_target_init,

	dm_linear_init,

	dm_stripe_init,

	dm_io_init,

	dm_kcopyd_init,

	dm_interface_init,

};
@@ -284,6 +285,7 @@ static void (*_exits[])(void) = { 
	dm_target_exit,

	dm_linear_exit,

	dm_stripe_exit,

	dm_io_exit,

	dm_kcopyd_exit,

	dm_interface_exit,

};

drivers/md/dm.h

+3 −0
Original line number Diff line number Diff line
@@ -118,6 +118,9 @@ int dm_lock_for_deletion(struct mapped_device *md); 
void dm_kobject_uevent(struct mapped_device *md, enum kobject_action action,

		       unsigned cookie);



int dm_io_init(void);

void dm_io_exit(void);



int dm_kcopyd_init(void);

void dm_kcopyd_exit(void);