[PATCH v2] landlock: Use kmem for landlock_object
Ayush Tiwari
ayushtiw0110 at gmail.com
Sat Mar 30 13:54:19 UTC 2024
Use kmem_cache replace kzalloc() calls with kmem_cache_zalloc() for
struct landlock_object and update the related dependencies to improve
memory allocation and deallocation performance. This patch does not
change kfree() and kfree_rcu() calls because according to kernel commit
ae65a5211d90("mm/slab: document kfree() as allowed for
kmem_cache_alloc() objects"), starting from kernel 6.4 with
CONFIG_SLOB, kfree() is safe to use for such objects.
Signed-off-by: Ayush Tiwari <ayushtiw0110 at gmail.com>
---
Changes in v2: Used clang-format and corrected the removal of kfree_rcu.
Tried to use KMEM macro but due to lack of cache pointer in that macro,
had to explicitly define landlock_object_cache, as done in security.c.
security/landlock/object.c | 12 +++++++++++-
security/landlock/object.h | 2 ++
security/landlock/setup.c | 1 +
3 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/security/landlock/object.c b/security/landlock/object.c
index 1f50612f0185..cfc367725624 100644
--- a/security/landlock/object.c
+++ b/security/landlock/object.c
@@ -17,6 +17,15 @@
#include "object.h"
+static struct kmem_cache *landlock_object_cache;
+
+void __init landlock_object_cache_init(void)
+{
+ landlock_object_cache = kmem_cache_create(
+ "landlock_object_cache", sizeof(struct landlock_object), 0,
+ SLAB_PANIC, NULL);
+}
+
struct landlock_object *
landlock_create_object(const struct landlock_object_underops *const underops,
void *const underobj)
@@ -25,7 +34,8 @@ landlock_create_object(const struct landlock_object_underops *const underops,
if (WARN_ON_ONCE(!underops || !underobj))
return ERR_PTR(-ENOENT);
- new_object = kzalloc(sizeof(*new_object), GFP_KERNEL_ACCOUNT);
+ new_object =
+ kmem_cache_zalloc(landlock_object_cache, GFP_KERNEL_ACCOUNT);
if (!new_object)
return ERR_PTR(-ENOMEM);
refcount_set(&new_object->usage, 1);
diff --git a/security/landlock/object.h b/security/landlock/object.h
index 5f28c35e8aa8..d9967ef16ec1 100644
--- a/security/landlock/object.h
+++ b/security/landlock/object.h
@@ -15,6 +15,8 @@
struct landlock_object;
+void __init landlock_object_cache_init(void);
+
/**
* struct landlock_object_underops - Operations on an underlying object
*/
diff --git a/security/landlock/setup.c b/security/landlock/setup.c
index f6dd33143b7f..525820fc03ec 100644
--- a/security/landlock/setup.c
+++ b/security/landlock/setup.c
@@ -33,6 +33,7 @@ const struct lsm_id landlock_lsmid = {
static int __init landlock_init(void)
{
+ landlock_object_cache_init();
landlock_add_cred_hooks();
landlock_add_ptrace_hooks();
landlock_add_fs_hooks();
--
2.40.1
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