[congwang:bpf 6/6] net/core/skmsg.c:420:3: warning: Assignment of function parameter has no effect outside the function. [uselessAssignmentArg]

[congwang:bpf 6/6] net/core/skmsg.c:420:3: warning: Assignment of function parameter has no effect outside the function. [uselessAssignmentArg]

[kernel test robot]

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CC: kbuild-all(a)lists.01.org
TO: Cong Wang <cong.wang@bytedance.com>

tree:   https://github.com/congwang/linux.git bpf
head:   f32ecd3b543074a848132bbdb4c94f96c4b9f83a
commit: f32ecd3b543074a848132bbdb4c94f96c4b9f83a [6/6] udp_bpf: use psock lock to serilize ->recvmsg()
:::::: branch date: 4 hours ago
:::::: commit date: 4 hours ago
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>


cppcheck possible warnings: (new ones prefixed by >>, may not real problems)

>> net/core/skmsg.c:420:3: warning: Assignment of function parameter has no effect outside the function. [uselessAssignmentArg]
     timeo = wait_woken(&wait, TASK_INTERRUPTIBLE, timeo);
     ^

vim +420 net/core/skmsg.c

604326b41a6fb9 Daniel Borkmann 2018-10-13  401  
53174844f4fa03 Cong Wang       2021-05-16  402  int sk_msg_wait_data(struct sock *sk, struct sk_psock *psock,
53174844f4fa03 Cong Wang       2021-05-16  403  		     struct sk_buff_head *queue, long timeo)
2bc793e3272a13 Cong Wang       2021-03-30  404  {
2bc793e3272a13 Cong Wang       2021-03-30  405  	DEFINE_WAIT_FUNC(wait, woken_wake_function);
2bc793e3272a13 Cong Wang       2021-03-30  406  	int ret = 0;
2bc793e3272a13 Cong Wang       2021-03-30  407  
2bc793e3272a13 Cong Wang       2021-03-30  408  	if (sk->sk_shutdown & RCV_SHUTDOWN)
2bc793e3272a13 Cong Wang       2021-03-30  409  		return 1;
2bc793e3272a13 Cong Wang       2021-03-30  410  
2bc793e3272a13 Cong Wang       2021-03-30  411  	if (!timeo)
2bc793e3272a13 Cong Wang       2021-03-30  412  		return ret;
2bc793e3272a13 Cong Wang       2021-03-30  413  
2bc793e3272a13 Cong Wang       2021-03-30  414  	add_wait_queue(sk_sleep(sk), &wait);
2bc793e3272a13 Cong Wang       2021-03-30  415  	sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
f32ecd3b543074 Cong Wang       2021-05-16  416  	mutex_unlock(&psock->lock);
f32ecd3b543074 Cong Wang       2021-05-16  417  	ret = !skb_queue_empty(&psock->ingress_skb) ||
f32ecd3b543074 Cong Wang       2021-05-16  418  	      !list_empty(&psock->ingress_msg) || !skb_queue_empty(queue);
f32ecd3b543074 Cong Wang       2021-05-16  419  	if (!ret)
f32ecd3b543074 Cong Wang       2021-05-16 @420  		timeo = wait_woken(&wait, TASK_INTERRUPTIBLE, timeo);
f32ecd3b543074 Cong Wang       2021-05-16  421  	mutex_lock(&psock->lock);
f32ecd3b543074 Cong Wang       2021-05-16  422  	ret = !skb_queue_empty(&psock->ingress_skb) ||
f32ecd3b543074 Cong Wang       2021-05-16  423  	      !list_empty(&psock->ingress_msg) || !skb_queue_empty(queue);
f32ecd3b543074 Cong Wang       2021-05-16  424  
2bc793e3272a13 Cong Wang       2021-03-30  425  	sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
2bc793e3272a13 Cong Wang       2021-03-30  426  	remove_wait_queue(sk_sleep(sk), &wait);
2bc793e3272a13 Cong Wang       2021-03-30  427  	return ret;
2bc793e3272a13 Cong Wang       2021-03-30  428  }
2bc793e3272a13 Cong Wang       2021-03-30  429  EXPORT_SYMBOL_GPL(sk_msg_wait_data);
2bc793e3272a13 Cong Wang       2021-03-30  430  

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