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-rw-r--r--include/net/bluetooth/l2cap.h10
-rw-r--r--net/bluetooth/l2cap_core.c86
2 files changed, 96 insertions, 0 deletions
diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
index 7b4cc5b98535..fb94cf13c777 100644
--- a/include/net/bluetooth/l2cap.h
+++ b/include/net/bluetooth/l2cap.h
@@ -584,6 +584,13 @@ struct l2cap_conn {
struct list_head chan_l;
struct mutex chan_lock;
struct kref ref;
+ struct list_head users;
+};
+
+struct l2cap_user {
+ struct list_head list;
+ int (*probe) (struct l2cap_conn *conn, struct l2cap_user *user);
+ void (*remove) (struct l2cap_conn *conn, struct l2cap_user *user);
};
#define L2CAP_INFO_CL_MTU_REQ_SENT 0x01
@@ -817,4 +824,7 @@ void __l2cap_physical_cfm(struct l2cap_chan *chan, int result);
void l2cap_conn_get(struct l2cap_conn *conn);
void l2cap_conn_put(struct l2cap_conn *conn);
+int l2cap_register_user(struct l2cap_conn *conn, struct l2cap_user *user);
+void l2cap_unregister_user(struct l2cap_conn *conn, struct l2cap_user *user);
+
#endif /* __L2CAP_H */
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index be9ad89339cd..eae1d9f90b68 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -1446,6 +1446,89 @@ static void l2cap_info_timeout(struct work_struct *work)
l2cap_conn_start(conn);
}
+/*
+ * l2cap_user
+ * External modules can register l2cap_user objects on l2cap_conn. The ->probe
+ * callback is called during registration. The ->remove callback is called
+ * during unregistration.
+ * An l2cap_user object can either be explicitly unregistered or when the
+ * underlying l2cap_conn object is deleted. This guarantees that l2cap->hcon,
+ * l2cap->hchan, .. are valid as long as the remove callback hasn't been called.
+ * External modules must own a reference to the l2cap_conn object if they intend
+ * to call l2cap_unregister_user(). The l2cap_conn object might get destroyed at
+ * any time if they don't.
+ */
+
+int l2cap_register_user(struct l2cap_conn *conn, struct l2cap_user *user)
+{
+ struct hci_dev *hdev = conn->hcon->hdev;
+ int ret;
+
+ /* We need to check whether l2cap_conn is registered. If it is not, we
+ * must not register the l2cap_user. l2cap_conn_del() is unregisters
+ * l2cap_conn objects, but doesn't provide its own locking. Instead, it
+ * relies on the parent hci_conn object to be locked. This itself relies
+ * on the hci_dev object to be locked. So we must lock the hci device
+ * here, too. */
+
+ hci_dev_lock(hdev);
+
+ if (user->list.next || user->list.prev) {
+ ret = -EINVAL;
+ goto out_unlock;
+ }
+
+ /* conn->hchan is NULL after l2cap_conn_del() was called */
+ if (!conn->hchan) {
+ ret = -ENODEV;
+ goto out_unlock;
+ }
+
+ ret = user->probe(conn, user);
+ if (ret)
+ goto out_unlock;
+
+ list_add(&user->list, &conn->users);
+ ret = 0;
+
+out_unlock:
+ hci_dev_unlock(hdev);
+ return ret;
+}
+EXPORT_SYMBOL(l2cap_register_user);
+
+void l2cap_unregister_user(struct l2cap_conn *conn, struct l2cap_user *user)
+{
+ struct hci_dev *hdev = conn->hcon->hdev;
+
+ hci_dev_lock(hdev);
+
+ if (!user->list.next || !user->list.prev)
+ goto out_unlock;
+
+ list_del(&user->list);
+ user->list.next = NULL;
+ user->list.prev = NULL;
+ user->remove(conn, user);
+
+out_unlock:
+ hci_dev_unlock(hdev);
+}
+EXPORT_SYMBOL(l2cap_unregister_user);
+
+static void l2cap_unregister_all_users(struct l2cap_conn *conn)
+{
+ struct l2cap_user *user;
+
+ while (!list_empty(&conn->users)) {
+ user = list_first_entry(&conn->users, struct l2cap_user, list);
+ list_del(&user->list);
+ user->list.next = NULL;
+ user->list.prev = NULL;
+ user->remove(conn, user);
+ }
+}
+
static void l2cap_conn_del(struct hci_conn *hcon, int err)
{
struct l2cap_conn *conn = hcon->l2cap_data;
@@ -1458,6 +1541,8 @@ static void l2cap_conn_del(struct hci_conn *hcon, int err)
kfree_skb(conn->rx_skb);
+ l2cap_unregister_all_users(conn);
+
mutex_lock(&conn->chan_lock);
/* Kill channels */
@@ -1550,6 +1635,7 @@ static struct l2cap_conn *l2cap_conn_add(struct hci_conn *hcon)
mutex_init(&conn->chan_lock);
INIT_LIST_HEAD(&conn->chan_l);
+ INIT_LIST_HEAD(&conn->users);
if (hcon->type == LE_LINK)
INIT_DELAYED_WORK(&conn->security_timer, security_timeout);