Bluetooth: SCO: fix sleeping under spinlock in sco_conn_ready

sco_conn_ready calls sleeping functions under conn->lock spinlock.

The critical section can be reduced: conn->hcon is modified only with
hdev->lock held. It is guaranteed to be held in sco_conn_ready, so
conn->lock is not needed to guard it.

Move taking conn->lock after lock_sock(parent). This also follows the
lock ordering lock_sock() > conn->lock elsewhere in the file.

Fixes: 27c24fda62b60 ("Bluetooth: switch to lock_sock in SCO")
Signed-off-by: Pauli Virtanen <pav@iki.fi>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
index 18826d4b9c0bf89efd965e513c4f380252238780..3a5479538e85878c8a157e59c690715676bf7dc7 100644 (file)
--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -1377,26 +1377,24 @@ static void sco_conn_ready(struct sco_conn *conn)
                sk->sk_state_change(sk);
                release_sock(sk);
        } else {
-               sco_conn_lock(conn);
-
-               if (!conn->hcon) {
-                       sco_conn_unlock(conn);
+               if (!conn->hcon)
                        return;
-               }
+
+               lockdep_assert_held(&conn->hcon->hdev->lock);
 
                parent = sco_get_sock_listen(&conn->hcon->src);
-               if (!parent) {
-                       sco_conn_unlock(conn);
+               if (!parent)
                        return;
-               }
 
                lock_sock(parent);
 
+               sco_conn_lock(conn);
+
                sk = sco_sock_alloc(sock_net(parent), NULL,
                                    BTPROTO_SCO, GFP_ATOMIC, 0);
                if (!sk) {
-                       release_sock(parent);
                        sco_conn_unlock(conn);
+                       release_sock(parent);
                        return;
                }
 
@@ -1417,9 +1415,9 @@ static void sco_conn_ready(struct sco_conn *conn)
                /* Wake up parent */
                parent->sk_data_ready(parent);
 
-               release_sock(parent);
-
                sco_conn_unlock(conn);
+
+               release_sock(parent);
        }
 }