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: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index a7663eba17e2..4a95e8fa3607 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -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);