[PATCH v3 4/7] mm: kmemleak: split __create_object into two functions

Liu Shixin
2023-10-18T09:30:46Z

__create_object() consists of two part, the first part allocate a
kmemleak object and initialize it, the second part insert it into
object tree. This function need kmemleak_lock but actually only the
second part need lock.

Split it into two functions, the first function __alloc_object only
allocate a kmemleak object, and the second function __link_object()
will initialize the object and insert it into object tree, use the
kmemleak_lock to protect __link_object() only.

Signed-off-by: Liu Shixin <liushixin2@huawei.com>
---
mm/kmemleak.c | 61 +++++++++++++++++++++++++++++++++------------------
1 file changed, 40 insertions(+), 21 deletions(-)

diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 289b3be5ee6e..064fc3695c6b 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -623,25 +623,15 @@ static noinline depot_stack_handle_t set_track_prepare(void)
return trace_handle;
}

-/*
- * Create the metadata (struct kmemleak_object) corresponding to an allocated
- * memory block and add it to the object_list and object_tree_root (or
- * object_phys_tree_root).
- */
-static void __create_object(unsigned long ptr, size_t size,
- int min_count, gfp_t gfp, bool is_phys)
+static struct kmemleak_object * __alloc_object(gfp_t gfp)
{
- unsigned long flags;
- struct kmemleak_object *object, *parent;
- struct rb_node **link, *rb_parent;
- unsigned long untagged_ptr;
- unsigned long untagged_objp;
+ struct kmemleak_object *object;

object = mem_pool_alloc(gfp);
if (!object) {
pr_warn("Cannot allocate a kmemleak_object structure\n");
kmemleak_disable();
- return;
+ return NULL;
}

INIT_LIST_HEAD(&object->object_list);
@@ -649,13 +639,8 @@ static void __create_object(unsigned long ptr, size_t size,
INIT_HLIST_HEAD(&object->area_list);
raw_spin_lock_init(&object->lock);
atomic_set(&object->use_count, 1);
- object->flags = OBJECT_ALLOCATED | (is_phys ? OBJECT_PHYS : 0);
- object->pointer = ptr;
- object->size = kfence_ksize((void *)ptr) ?: size;
object->excess_ref = 0;
- object->min_count = min_count;
object->count = 0; /* white color initially */
- object->jiffies = jiffies;
object->checksum = 0;
object->del_state = 0;

@@ -680,7 +665,23 @@ static void __create_object(unsigned long ptr, size_t size,
/* kernel backtrace */
object->trace_handle = set_track_prepare();

- raw_spin_lock_irqsave(&kmemleak_lock, flags);
+ return object;
+}
+
+static void __link_object(struct kmemleak_object *object, unsigned long ptr,
+ size_t size, int min_count, bool is_phys)
+{
+
+ struct kmemleak_object *parent;
+ struct rb_node **link, *rb_parent;
+ unsigned long untagged_ptr;
+ unsigned long untagged_objp;
+
+ object->flags = OBJECT_ALLOCATED | (is_phys ? OBJECT_PHYS : 0);
+ object->pointer = ptr;
+ object->size = kfence_ksize((void *)ptr) ?: size;
+ object->min_count = min_count;
+ object->jiffies = jiffies;

untagged_ptr = (unsigned long)kasan_reset_tag((void *)ptr);
/*
@@ -711,14 +712,32 @@ static void __create_object(unsigned long ptr, size_t size,
*/
dump_object_info(parent);
kmem_cache_free(object_cache, object);
- goto out;
+ return;
}
}
rb_link_node(&object->rb_node, rb_parent, link);
rb_insert_color(&object->rb_node, is_phys ? &object_phys_tree_root :
&object_tree_root);
list_add_tail_rcu(&object->object_list, &object_list);
-out:
+}
+
+/*
+ * Create the metadata (struct kmemleak_object) corresponding to an allocated
+ * memory block and add it to the object_list and object_tree_root (or
+ * object_phys_tree_root).
+ */
+static void __create_object(unsigned long ptr, size_t size,
+ int min_count, gfp_t gfp, bool is_phys)
+{
+ struct kmemleak_object *object;
+ unsigned long flags;
+
+ object = __alloc_object(gfp);
+ if (!object)
+ return;
+
+ raw_spin_lock_irqsave(&kmemleak_lock, flags);
+ __link_object(object, ptr, size, min_count, is_phys);
raw_spin_unlock_irqrestore(&kmemleak_lock, flags);
}

--
2.25.1