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>
diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
index 3a2e6a2..b0d264e 100644
--- a/drivers/md/dm-io.c
+++ b/drivers/md/dm-io.c
@@ -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 @@
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 @@
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 @@
&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;
+}
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 724efc6..473f0c3 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -275,6 +275,7 @@
dm_target_init,
dm_linear_init,
dm_stripe_init,
+ dm_io_init,
dm_kcopyd_init,
dm_interface_init,
};
@@ -284,6 +285,7 @@
dm_target_exit,
dm_linear_exit,
dm_stripe_exit,
+ dm_io_exit,
dm_kcopyd_exit,
dm_interface_exit,
};
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index a7663eb..4a95e8f 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -118,6 +118,9 @@
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);
