Bluetooth: Convert link keys list to use RCU

This patch converts the hdev->link_keys list to be protected through
RCU, thereby eliminating the need to hold the hdev lock while accessing
the list.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

1 files changed, 18 insertions, 19 deletions

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index a67a4b8e4e1c..5c319a49a5a4 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -274,15 +274,13 @@ static const struct file_operations inquiry_cache_fops = {
 static int link_keys_show(struct seq_file *f, void *ptr)
 {
         struct hci_dev *hdev = f->private;
-        struct list_head *p, *n;
+        struct link_key *key;
 
-        hci_dev_lock(hdev);
-        list_for_each_safe(p, n, &hdev->link_keys) {
-                struct link_key *key = list_entry(p, struct link_key, list);
+        rcu_read_lock();
+        list_for_each_entry_rcu(key, &hdev->link_keys, list)
                 seq_printf(f, "%pMR %u %*phN %u\n", &key->bdaddr, key->type,
                            HCI_LINK_KEY_SIZE, key->val, key->pin_len);
-        }
-        hci_dev_unlock(hdev);
+        rcu_read_unlock();
 
         return 0;
 }
@@ -3101,15 +3099,11 @@ void hci_uuids_clear(struct hci_dev *hdev)
 
 void hci_link_keys_clear(struct hci_dev *hdev)
 {
-        struct list_head *p, *n;
-
-        list_for_each_safe(p, n, &hdev->link_keys) {
-                struct link_key *key;
-
-                key = list_entry(p, struct link_key, list);
+        struct link_key *key;
 
-                list_del(p);
-                kfree(key);
+        list_for_each_entry_rcu(key, &hdev->link_keys, list) {
+                list_del_rcu(&key->list);
+                kfree_rcu(key, rcu);
         }
 }
 
@@ -3137,9 +3131,14 @@ struct link_key *hci_find_link_key(struct hci_dev *hdev, bdaddr_t *bdaddr)
 {
         struct link_key *k;
 
-        list_for_each_entry(k, &hdev->link_keys, list)
-                if (bacmp(bdaddr, &k->bdaddr) == 0)
+        rcu_read_lock();
+        list_for_each_entry_rcu(k, &hdev->link_keys, list) {
+                if (bacmp(bdaddr, &k->bdaddr) == 0) {
+                        rcu_read_unlock();
                         return k;
+                }
+        }
+        rcu_read_unlock();
 
         return NULL;
 }
@@ -3290,7 +3289,7 @@ struct link_key *hci_add_link_key(struct hci_dev *hdev, struct hci_conn *conn,
                 key = kzalloc(sizeof(*key), GFP_KERNEL);
                 if (!key)
                         return NULL;
-                list_add(&key->list, &hdev->link_keys);
+                list_add_rcu(&key->list, &hdev->link_keys);
         }
 
         BT_DBG("%s key for %pMR type %u", hdev->name, bdaddr, type);
@@ -3383,8 +3382,8 @@ int hci_remove_link_key(struct hci_dev *hdev, bdaddr_t *bdaddr)
 
         BT_DBG("%s removing %pMR", hdev->name, bdaddr);
 
-        list_del(&key->list);
-        kfree(key);
+        list_del_rcu(&key->list);
+        kfree_rcu(key, rcu);
 
         return 0;
 }