Commit b548b17a authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

tcp: tcp_wfree() refactoring 



Use try_cmpxchg() (instead of cmpxchg()) in a more readable way.

oval = smp_load_acquire(&sk->sk_tsq_flags);
do {
	...
} while (!try_cmpxchg(&sk->sk_tsq_flags, &oval, nval));

Reduce indentation level.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20221110190239.3531280-1-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent fac30731

net/ipv4/tcp_output.c

+14 −17
Original line number Diff line number Diff line
@@ -1139,6 +1139,8 @@ void tcp_wfree(struct sk_buff *skb) 
	struct sock *sk = skb->sk;

	struct tcp_sock *tp = tcp_sk(sk);

	unsigned long flags, nval, oval;

	struct tsq_tasklet *tsq;

	bool empty;



	/* Keep one reference on sk_wmem_alloc.

	 * Will be released by sk_free() from here or tcp_tasklet_func()
@@ -1155,17 +1157,13 @@ void tcp_wfree(struct sk_buff *skb) 
	if (refcount_read(&sk->sk_wmem_alloc) >= SKB_TRUESIZE(1) && this_cpu_ksoftirqd() == current)

		goto out;



	for (oval = READ_ONCE(sk->sk_tsq_flags);; oval = nval) {

		struct tsq_tasklet *tsq;

		bool empty;



	oval = smp_load_acquire(&sk->sk_tsq_flags);

	do {

		if (!(oval & TSQF_THROTTLED) || (oval & TSQF_QUEUED))

			goto out;



		nval = (oval & ~TSQF_THROTTLED) | TSQF_QUEUED;

		nval = cmpxchg(&sk->sk_tsq_flags, oval, nval);

		if (nval != oval)

			continue;

	} while (!try_cmpxchg(&sk->sk_tsq_flags, &oval, nval));



	/* queue this socket to tasklet queue */

	local_irq_save(flags);
@@ -1176,7 +1174,6 @@ void tcp_wfree(struct sk_buff *skb) 
		tasklet_schedule(&tsq->tasklet);

	local_irq_restore(flags);

	return;

	}

out:

	sk_free(sk);

}