[Bluetooth] Add locking for bt_proto array manipulation

The bt_proto array needs to be protected by some kind of locking to
prevent a race condition between bt_sock_create and bt_sock_register.

And in addition all calls to sk_alloc need to be made GFP_ATOMIC now.

Signed-off-by: Masatake YAMATO <jet@gyve.org>
Signed-off-by: Frederik Deweerdt <frederik.deweerdt@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

net/bluetooth/hidp/sock.c

@@ -256,7 +256,7 @@ static int hidp_sock_create(struct socket *sock, int protocol)
 	if (sock->type != SOCK_RAW)
 		return -ESOCKTNOSUPPORT;
 
-	sk = sk_alloc(PF_BLUETOOTH, GFP_KERNEL, &hidp_proto, 1);
+	sk = sk_alloc(PF_BLUETOOTH, GFP_ATOMIC, &hidp_proto, 1);
 	if (!sk)
 		return -ENOMEM;