1 struct foo {
2 struct list_head list;
3 int key;
4 int data;
5 };
6
7 LIST_HEAD(mylist);
8 DEFINE_SPINLOCK(mylock);
9 struct foo *cache;
10
11 int search(int key, int *data)
12 {
13 struct foo *p;
14
15 rcu_read_lock();
16 p = rcu_dereference(cache);
17 if (p != NULL && p->key == key)
18 goto found;
19 list_for_each_entry_rcu(p, &mylist, list)
20 if (p->key == key) {
21 rcu_assign_pointer(cache, p);
22 goto found;
23 }
24 rcu_read_unlock();
25 return -ENOENT;
26 found:
27 *data = p->data;
28 rcu_read_unlock();
29 return 0;
30 }
31
32 int insert(int key, int data)
33 {
34 struct foo *p = kmalloc(sizeof(*p), GFP_KERNEL);
35
36 if (p == NULL)
37 return -ENOMEM;
38 p->key = key;
39 p->data = data;
40 spin_lock(&mylock);
41 list_add_rcu(&p->list, &mylist);
42 spin_unlock(&mylock);
43 }
44
45 int delete(int key)
46 {
47 struct foo *p;
48
49 spin_lock(&mylock);
50 list_for_each_entry(p, &mylist, list)
51 if (p->key == key) {
52 list_del_rcu(&p->list);
53 RCU_INIT_POINTER(cache, NULL);
54 spin_unlock(&mylock);
55 synchronize_rcu();
56 free(p);
57 return 0;
58 }
59 spin_unlock(&mylock);
60 return -ENOENT;
61 }
Can you spot the additional bug?
