HID: bt: Move hid_add_device() call to after hidp_session() has started.

Move the call to hid_add_device() (which calls a device's probe() function)
to after the kernel_thread() call which starts the hidp_session() thread.
This ensures the Bluetooth receive socket is fully running by the time a
device's probe() function is called. This way, a device can communicate
(send and receive) with the Bluetooth device from its probe() function.

Signed-off-by: Alan Ott <alan@signal11.us>
Acked-by: Gustavo F. Padovan <padovan@profusion.mobi>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

2 files changed, 23 insertions, 8 deletions

diff --git a/net/bluetooth/hidp/core.c b/net/bluetooth/hidp/core.c
index 29544c21f4b5..67cc4bc82c68 100644
--- a/net/bluetooth/hidp/core.c
+++ b/net/bluetooth/hidp/core.c
@@ -563,6 +563,8 @@ static int hidp_session(void *arg)
         init_waitqueue_entry(&intr_wait, current);
         add_wait_queue(sk_sleep(ctrl_sk), &ctrl_wait);
         add_wait_queue(sk_sleep(intr_sk), &intr_wait);
+        session->waiting_for_startup = 0;
+        wake_up_interruptible(&session->startup_queue);
         while (!atomic_read(&session->terminate)) {
                 set_current_state(TASK_INTERRUPTIBLE);
 
@@ -754,6 +756,8 @@ static struct hid_ll_driver hidp_hid_driver = {
         .hidinput_input_event = hidp_hidinput_event,
 };
 
+/* This function sets up the hid device. It does not add it
+   to the HID system. That is done in hidp_add_connection(). */
 static int hidp_setup_hid(struct hidp_session *session,
                                 struct hidp_connadd_req *req)
 {
@@ -795,16 +799,8 @@ static int hidp_setup_hid(struct hidp_session *session,
 
         hid->hid_output_raw_report = hidp_output_raw_report;
 
-        err = hid_add_device(hid);
-        if (err < 0)
-                goto failed;
-
         return 0;
 
-failed:
-        hid_destroy_device(hid);
-        session->hid = NULL;
-
 fault:
         kfree(session->rd_data);
         session->rd_data = NULL;
@@ -853,6 +849,8 @@ int hidp_add_connection(struct hidp_connadd_req *req, struct socket *ctrl_sock,
         skb_queue_head_init(&session->ctrl_transmit);
         skb_queue_head_init(&session->intr_transmit);
 
+        init_waitqueue_head(&session->startup_queue);
+        session->waiting_for_startup = 1;
         session->flags   = req->flags & (1 << HIDP_BLUETOOTH_VENDOR_ID);
         session->idle_to = req->idle_to;
 
@@ -875,6 +873,14 @@ int hidp_add_connection(struct hidp_connadd_req *req, struct socket *ctrl_sock,
         err = kernel_thread(hidp_session, session, CLONE_KERNEL);
         if (err < 0)
                 goto unlink;
+        while (session->waiting_for_startup) {
+                wait_event_interruptible(session->startup_queue,
+                        !session->waiting_for_startup);
+        }
+
+        err = hid_add_device(session->hid);
+        if (err < 0)
+                goto err_add_device;
 
         if (session->input) {
                 hidp_send_ctrl_message(session,
@@ -888,6 +894,12 @@ int hidp_add_connection(struct hidp_connadd_req *req, struct socket *ctrl_sock,
         up_write(&hidp_session_sem);
         return 0;
 
+err_add_device:
+        hid_destroy_device(session->hid);
+        session->hid = NULL;
+        atomic_inc(&session->terminate);
+        hidp_schedule(session);
+
 unlink:
         hidp_del_timer(session);
 
diff --git a/net/bluetooth/hidp/hidp.h b/net/bluetooth/hidp/hidp.h
index 8d934a19da0a..2cc35dc8fa03 100644
--- a/net/bluetooth/hidp/hidp.h
+++ b/net/bluetooth/hidp/hidp.h
@@ -157,6 +157,9 @@ struct hidp_session {
         /* Report descriptor */
         __u8 *rd_data;
         uint rd_size;
+
+        wait_queue_head_t startup_queue;
+        int waiting_for_startup;
 };
 
 static inline void hidp_schedule(struct hidp_session *session)