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mptcp: defer work schedule until mptcp lock is released

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Don't schedule the work queue right away, instead defer this
to the lock release callback.

This has the advantage that it will give recv path a chance to
complete -- this might have moved all pending packets from the
subflow to the mptcp receive queue, which allows to avoid the
schedule_work().

Co-developed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Paolo Abeni 2020-02-26 10:14:52 +01:00 committed by David S. Miller
parent 2e52213c79
commit 14c441b564
1 changed files with 36 additions and 2 deletions
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38
net/mptcp/protocol.c
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@ -238,9 +238,16 @@ void mptcp_data_ready(struct sock *sk, struct sock *ssk)
if (atomic_read(&sk->sk_rmem_alloc) > READ_ONCE(sk->sk_rcvbuf))
goto wake;
if (schedule_work(&msk->work))
sock_hold((struct sock *)msk);
/* mptcp socket is owned, release_cb should retry */
if (!test_and_set_bit(TCP_DELACK_TIMER_DEFERRED,
&sk->sk_tsq_flags)) {
sock_hold(sk);
/* need to try again, its possible release_cb() has already
* been called after the test_and_set_bit() above.
*/
move_skbs_to_msk(msk, ssk);
}
wake:
sk->sk_data_ready(sk);
}
@ -941,6 +948,32 @@ static int mptcp_getsockopt(struct sock *sk, int level, int optname,
return -EOPNOTSUPP;
}
#define MPTCP_DEFERRED_ALL TCPF_DELACK_TIMER_DEFERRED
/* this is very alike tcp_release_cb() but we must handle differently a
* different set of events
*/
static void mptcp_release_cb(struct sock *sk)
{
unsigned long flags, nflags;
do {
flags = sk->sk_tsq_flags;
if (!(flags & MPTCP_DEFERRED_ALL))
return;
nflags = flags & ~MPTCP_DEFERRED_ALL;
} while (cmpxchg(&sk->sk_tsq_flags, flags, nflags) != flags);
if (flags & TCPF_DELACK_TIMER_DEFERRED) {
struct mptcp_sock *msk = mptcp_sk(sk);
struct sock *ssk;
ssk = mptcp_subflow_recv_lookup(msk);
if (!ssk || !schedule_work(&msk->work))
__sock_put(sk);
}
}
static int mptcp_get_port(struct sock *sk, unsigned short snum)
{
struct mptcp_sock *msk = mptcp_sk(sk);
@ -1016,6 +1049,7 @@ static struct proto mptcp_prot = {
.destroy = mptcp_destroy,
.sendmsg = mptcp_sendmsg,
.recvmsg = mptcp_recvmsg,
.release_cb = mptcp_release_cb,
.hash = inet_hash,
.unhash = inet_unhash,
.get_port = mptcp_get_port,