Bluetooth: bnep: fix possible might sleep error in bnep_session

It looks like bnep_session has same pattern as the issue reported in
old rfcomm:

	while (1) {
		set_current_state(TASK_INTERRUPTIBLE);
		if (condition)
			break;
		// may call might_sleep here
		schedule();
	}
	__set_current_state(TASK_RUNNING);

Which fixed at:
	dfb2fae Bluetooth: Fix nested sleeps

So let's fix it at the same way, also follow the suggestion of:
https://lwn.net/Articles/628628/

Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Reviewed-by: AL Yu-Chen Cho <acho@suse.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

1 files changed, 5 insertions, 6 deletions

diff --git a/net/bluetooth/bnep/core.c b/net/bluetooth/bnep/core.c
index 9a40013da915..7b3965861013 100644
--- a/net/bluetooth/bnep/core.c
+++ b/net/bluetooth/bnep/core.c
@@ -481,16 +481,16 @@ static int bnep_session(void *arg)
         struct net_device *dev = s->dev;
         struct sock *sk = s->sock->sk;
         struct sk_buff *skb;
-        wait_queue_t wait;
+        DEFINE_WAIT_FUNC(wait, woken_wake_function);
 
         BT_DBG("");
 
         set_user_nice(current, -15);
 
-        init_waitqueue_entry(&wait, current);
         add_wait_queue(sk_sleep(sk), &wait);
         while (1) {
-                set_current_state(TASK_INTERRUPTIBLE);
+                /* Ensure session->terminate is updated */
+                smp_mb__before_atomic();
 
                 if (atomic_read(&s->terminate))
                         break;
@@ -512,9 +512,8 @@ static int bnep_session(void *arg)
                                 break;
                 netif_wake_queue(dev);
 
-                schedule();
+                wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
         }
-        __set_current_state(TASK_RUNNING);
         remove_wait_queue(sk_sleep(sk), &wait);
 
         /* Cleanup session */
@@ -663,7 +662,7 @@ int bnep_del_connection(struct bnep_conndel_req *req)
         s = __bnep_get_session(req->dst);
         if (s) {
                 atomic_inc(&s->terminate);
-                wake_up_process(s->task);
+                wake_up_interruptible(sk_sleep(s->sock->sk));
         } else
                 err = -ENOENT;