From 9eba32b86d17ef87131fa0bce43c614904ab5781 Mon Sep 17 00:00:00 2001 From: Marcel Holtmann Date: Sat, 22 Aug 2009 14:19:26 -0700 Subject: [PATCH] Bluetooth: Add extra device reference counting for connections The device model itself has no real usable reference counting at the moment and this causes problems if parents are deleted before their children. The device model itself handles the memory details of this correctly, but the uevent order is not consistent. This causes various problems for systems like HAL or even X. So until device_put() does a proper cleanup, the device for Bluetooth connection will be protected with an extra reference counting to ensure the correct order of uevents when connections are terminated. This is not an automatic feature. Higher Bluetooth layers like HIDP or BNEP should grab this new reference to ensure that their uevents are send before the ones from the parent device. Based on a report by Brian Rogers Signed-off-by: Marcel Holtmann --- include/net/bluetooth/hci_core.h | 4 ++++ net/bluetooth/hci_conn.c | 17 ++++++++++++++++- net/bluetooth/hci_event.c | 2 ++ 3 files changed, 22 insertions(+), 1 deletion(-) diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h index c4ca4228b083..25b8a0345a6a 100644 --- a/include/net/bluetooth/hci_core.h +++ b/include/net/bluetooth/hci_core.h @@ -187,6 +187,7 @@ struct hci_conn { struct work_struct work_del; struct device dev; + atomic_t devref; struct hci_dev *hdev; void *l2cap_data; @@ -339,6 +340,9 @@ int hci_conn_switch_role(struct hci_conn *conn, __u8 role); void hci_conn_enter_active_mode(struct hci_conn *conn); void hci_conn_enter_sniff_mode(struct hci_conn *conn); +void hci_conn_hold_device(struct hci_conn *conn); +void hci_conn_put_device(struct hci_conn *conn); + static inline void hci_conn_hold(struct hci_conn *conn) { atomic_inc(&conn->refcnt); diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c index fa47d5d84f5c..a9750984f772 100644 --- a/net/bluetooth/hci_conn.c +++ b/net/bluetooth/hci_conn.c @@ -246,6 +246,8 @@ struct hci_conn *hci_conn_add(struct hci_dev *hdev, int type, bdaddr_t *dst) if (hdev->notify) hdev->notify(hdev, HCI_NOTIFY_CONN_ADD); + atomic_set(&conn->devref, 0); + hci_conn_init_sysfs(conn); tasklet_enable(&hdev->tx_task); @@ -288,7 +290,7 @@ int hci_conn_del(struct hci_conn *conn) skb_queue_purge(&conn->data_q); - hci_conn_del_sysfs(conn); + hci_conn_put_device(conn); hci_dev_put(hdev); @@ -583,6 +585,19 @@ void hci_conn_check_pending(struct hci_dev *hdev) hci_dev_unlock(hdev); } +void hci_conn_hold_device(struct hci_conn *conn) +{ + atomic_inc(&conn->devref); +} +EXPORT_SYMBOL(hci_conn_hold_device); + +void hci_conn_put_device(struct hci_conn *conn) +{ + if (atomic_dec_and_test(&conn->devref)) + hci_conn_del_sysfs(conn); +} +EXPORT_SYMBOL(hci_conn_put_device); + int hci_get_conn_list(void __user *arg) { struct hci_conn_list_req req, *cl; diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c index 184ba0a88ec0..e99fe385fba2 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -887,6 +887,7 @@ static inline void hci_conn_complete_evt(struct hci_dev *hdev, struct sk_buff *s } else conn->state = BT_CONNECTED; + hci_conn_hold_device(conn); hci_conn_add_sysfs(conn); if (test_bit(HCI_AUTH, &hdev->flags)) @@ -1693,6 +1694,7 @@ static inline void hci_sync_conn_complete_evt(struct hci_dev *hdev, struct sk_bu conn->handle = __le16_to_cpu(ev->handle); conn->state = BT_CONNECTED; + hci_conn_hold_device(conn); hci_conn_add_sysfs(conn); break; -- 2.39.2