[PATCH net-next 5/5] mptcp: make the locking tx schema more readable
From: Mat Martineau <hidden>
Date: 2021-08-27 00:45:09
Also in:
mptcp
Subsystem:
networking [general], networking [mptcp], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Matthieu Baerts, Mat Martineau, Linus Torvalds
From: Paolo Abeni <pabeni@redhat.com> Florian noted the locking schema used by __mptcp_push_pending() is hard to follow, let's add some more descriptive comments and drop an unneeded and confusing check. Suggested-by: Florian Westphal <fw@strlen.de> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <redacted> --- net/mptcp/protocol.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 1a408395e78f..ade648c3512b 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c@@ -1515,15 +1515,19 @@ void __mptcp_push_pending(struct sock *sk, unsigned int flags) mptcp_flush_join_list(msk); ssk = mptcp_subflow_get_send(msk); - /* try to keep the subflow socket lock across - * consecutive xmit on the same socket + /* First check. If the ssk has changed since + * the last round, release prev_ssk */ if (ssk != prev_ssk && prev_ssk) mptcp_push_release(sk, prev_ssk, &info); if (!ssk) goto out; - if (ssk != prev_ssk || !prev_ssk) + /* Need to lock the new subflow only if different + * from the previous one, otherwise we are still + * helding the relevant lock + */ + if (ssk != prev_ssk) lock_sock(ssk); /* keep it simple and always provide a new skb for the
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2.33.0