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Commit 3f926af3 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

net: use skb_queue_empty_lockless() in busy poll contexts 



Busy polling usually runs without locks.
Let's use skb_queue_empty_lockless() instead of skb_queue_empty()

Also uses READ_ONCE() in __skb_try_recv_datagram() to address
a similar potential problem.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 3ef7cf57

drivers/crypto/chelsio/chtls/chtls_io.c

+1 −1
Original line number Diff line number Diff line
@@ -1702,7 +1702,7 @@ int chtls_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, 
		return peekmsg(sk, msg, len, nonblock, flags);



	if (sk_can_busy_loop(sk) &&

	    skb_queue_empty(&sk->sk_receive_queue) &&

	    skb_queue_empty_lockless(&sk->sk_receive_queue) &&

	    sk->sk_state == TCP_ESTABLISHED)

		sk_busy_loop(sk, nonblock);

drivers/nvme/host/tcp.c

+1 −1
Original line number Diff line number Diff line
@@ -2219,7 +2219,7 @@ static int nvme_tcp_poll(struct blk_mq_hw_ctx *hctx) 
	struct nvme_tcp_queue *queue = hctx->driver_data;

	struct sock *sk = queue->sock->sk;



	if (sk_can_busy_loop(sk) && skb_queue_empty(&sk->sk_receive_queue))

	if (sk_can_busy_loop(sk) && skb_queue_empty_lockless(&sk->sk_receive_queue))

		sk_busy_loop(sk, true);

	nvme_tcp_try_recv(queue);

	return queue->nr_cqe;

net/core/datagram.c

+1 −1
Original line number Diff line number Diff line
@@ -278,7 +278,7 @@ struct sk_buff *__skb_try_recv_datagram(struct sock *sk, unsigned int flags, 
			break;



		sk_busy_loop(sk, flags & MSG_DONTWAIT);

	} while (sk->sk_receive_queue.prev != *last);

	} while (READ_ONCE(sk->sk_receive_queue.prev) != *last);



	error = -EAGAIN;

net/core/sock.c

+1 −1
Original line number Diff line number Diff line
@@ -3600,7 +3600,7 @@ bool sk_busy_loop_end(void *p, unsigned long start_time) 
{

	struct sock *sk = p;



	return !skb_queue_empty(&sk->sk_receive_queue) ||

	return !skb_queue_empty_lockless(&sk->sk_receive_queue) ||

	       sk_busy_loop_timeout(sk, start_time);

}

EXPORT_SYMBOL(sk_busy_loop_end);

net/ipv4/tcp.c

+1 −1
Original line number Diff line number Diff line
@@ -1964,7 +1964,7 @@ int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock, 
	if (unlikely(flags & MSG_ERRQUEUE))

		return inet_recv_error(sk, msg, len, addr_len);



	if (sk_can_busy_loop(sk) && skb_queue_empty(&sk->sk_receive_queue) &&

	if (sk_can_busy_loop(sk) && skb_queue_empty_lockless(&sk->sk_receive_queue) &&

	    (sk->sk_state == TCP_ESTABLISHED))

		sk_busy_loop(sk, nonblock);