Bluetooth: Let HIDP grab the device reference for connections

The core exports the hci_conn_hold_device() and hci_conn_put_device()
functions for device reference of connections. Use this to ensure that
the uevents from the parent are send after the child ones.

Based on a report by Brian Rogers <brian@xyzw.org>

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

2 files changed, 43 insertions, 21 deletions

diff --git a/net/bluetooth/hidp/core.c b/net/bluetooth/hidp/core.c
index f912d6537180..09bedeb5579c 100644
--- a/net/bluetooth/hidp/core.c
+++ b/net/bluetooth/hidp/core.c
@@ -93,10 +93,14 @@ static void __hidp_link_session(struct hidp_session *session)
 {
         __module_get(THIS_MODULE);
         list_add(&session->list, &hidp_session_list);
+
+        hci_conn_hold_device(session->conn);
 }
 
 static void __hidp_unlink_session(struct hidp_session *session)
 {
+        hci_conn_put_device(session->conn);
+
         list_del(&session->list);
         module_put(THIS_MODULE);
 }
@@ -577,7 +581,9 @@ static int hidp_session(void *arg)
                         hidinput_disconnect(session->hid);
                 if (session->hid->claimed & HID_CLAIMED_HIDRAW)
                         hidraw_disconnect(session->hid);
+
                 hid_destroy_device(session->hid);
+                session->hid = NULL;
         }
 
         /* Wakeup user-space polling for socket errors */
@@ -605,25 +611,27 @@ static struct device *hidp_get_device(struct hidp_session *session)
 {
         bdaddr_t *src = &bt_sk(session->ctrl_sock->sk)->src;
         bdaddr_t *dst = &bt_sk(session->ctrl_sock->sk)->dst;
+        struct device *device = NULL;
         struct hci_dev *hdev;
-        struct hci_conn *conn;
 
         hdev = hci_get_route(dst, src);
         if (!hdev)
                 return NULL;
 
-        conn = hci_conn_hash_lookup_ba(hdev, ACL_LINK, dst);
+        session->conn = hci_conn_hash_lookup_ba(hdev, ACL_LINK, dst);
+        if (session->conn)
+                device = &session->conn->dev;
 
         hci_dev_put(hdev);
 
-        return conn ? &conn->dev : NULL;
+        return device;
 }
 
 static int hidp_setup_input(struct hidp_session *session,
                                 struct hidp_connadd_req *req)
 {
         struct input_dev *input;
-        int i;
+        int err, i;
 
         input = input_allocate_device();
         if (!input)
@@ -670,7 +678,13 @@ static int hidp_setup_input(struct hidp_session *session,
 
         input->event = hidp_input_event;
 
-        return input_register_device(input);
+        err = input_register_device(input);
+        if (err < 0) {
+                hci_conn_put_device(session->conn);
+                return err;
+        }
+
+        return 0;
 }
 
 static int hidp_open(struct hid_device *hid)
@@ -752,13 +766,11 @@ static int hidp_setup_hid(struct hidp_session *session,
 {
         struct hid_device *hid;
         bdaddr_t src, dst;
-        int ret;
+        int err;
 
         hid = hid_allocate_device();
-        if (IS_ERR(hid)) {
-                ret = PTR_ERR(session->hid);
-                goto err;
-        }
+        if (IS_ERR(hid))
+                return PTR_ERR(session->hid);
 
         session->hid = hid;
         session->req = req;
@@ -780,16 +792,17 @@ static int hidp_setup_hid(struct hidp_session *session,
         hid->dev.parent = hidp_get_device(session);
         hid->ll_driver = &hidp_hid_driver;
 
-        ret = hid_add_device(hid);
-        if (ret)
-                goto err_hid;
+        err = hid_add_device(hid);
+        if (err < 0)
+                goto failed;
 
         return 0;
-err_hid:
+
+failed:
         hid_destroy_device(hid);
         session->hid = NULL;
-err:
-        return ret;
+
+        return err;
 }
 
 int hidp_add_connection(struct hidp_connadd_req *req, struct socket *ctrl_sock, struct socket *intr_sock)
@@ -839,13 +852,13 @@ int hidp_add_connection(struct hidp_connadd_req *req, struct socket *ctrl_sock,
         if (req->rd_size > 0) {
                 err = hidp_setup_hid(session, req);
                 if (err && err != -ENODEV)
-                        goto err_skb;
+                        goto purge;
         }
 
         if (!session->hid) {
                 err = hidp_setup_input(session, req);
                 if (err < 0)
-                        goto err_skb;
+                        goto purge;
         }
 
         __hidp_link_session(session);
@@ -873,13 +886,20 @@ unlink:
 
         __hidp_unlink_session(session);
 
-        if (session->input)
+        if (session->input) {
                 input_unregister_device(session->input);
-        if (session->hid)
+                session->input = NULL;
+        }
+
+        if (session->hid) {
                 hid_destroy_device(session->hid);
-err_skb:
+                session->hid = NULL;
+        }
+
+purge:
         skb_queue_purge(&session->ctrl_transmit);
         skb_queue_purge(&session->intr_transmit);
+
 failed:
         up_write(&hidp_session_sem);
 
diff --git a/net/bluetooth/hidp/hidp.h b/net/bluetooth/hidp/hidp.h
index e503c89057ad..faf3d74c3586 100644
--- a/net/bluetooth/hidp/hidp.h
+++ b/net/bluetooth/hidp/hidp.h
@@ -126,6 +126,8 @@ int hidp_get_conninfo(struct hidp_conninfo *ci);
 struct hidp_session {
         struct list_head list;
 
+        struct hci_conn *conn;
+
         struct socket *ctrl_sock;
         struct socket *intr_sock;