From: Paolo Abeni pabeni@redhat.com
[ Upstream commit c2e6048fa1cf2228063aec299f93ac6eb256b457 ]
If we receive a MPTCP_PUSH_PENDING even from a subflow when mptcp_release_cb() is serving the previous one, the latter will be delayed up to the next release_sock(msk).
Address the issue implementing a test/serve loop for such event.
Additionally rename the push helper to __mptcp_push_pending() to be more consistent with the existing code.
Fixes: 6e628cd3a8f7 ("mptcp: use mptcp release_cb for delayed tasks") Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Mat Martineau mathew.j.martineau@linux.intel.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/mptcp/protocol.c | 33 +++++++++++++++++++++------------ 1 file changed, 21 insertions(+), 12 deletions(-)
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index c3299a4568a0..7cbb544c6d02 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1442,7 +1442,7 @@ static void mptcp_push_release(struct sock *sk, struct sock *ssk, release_sock(ssk); }
-static void mptcp_push_pending(struct sock *sk, unsigned int flags) +static void __mptcp_push_pending(struct sock *sk, unsigned int flags) { struct sock *prev_ssk = NULL, *ssk = NULL; struct mptcp_sock *msk = mptcp_sk(sk); @@ -1681,14 +1681,14 @@ static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
wait_for_memory: set_bit(MPTCP_NOSPACE, &msk->flags); - mptcp_push_pending(sk, msg->msg_flags); + __mptcp_push_pending(sk, msg->msg_flags); ret = sk_stream_wait_memory(sk, &timeo); if (ret) goto out; }
if (copied) - mptcp_push_pending(sk, msg->msg_flags); + __mptcp_push_pending(sk, msg->msg_flags);
out: release_sock(sk); @@ -2944,13 +2944,14 @@ static void mptcp_release_cb(struct sock *sk) { unsigned long flags, nflags;
- /* push_pending may touch wmem_reserved, do it before the later - * cleanup - */ - if (test_and_clear_bit(MPTCP_CLEAN_UNA, &mptcp_sk(sk)->flags)) - __mptcp_clean_una(sk); - if (test_and_clear_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->flags)) { - /* mptcp_push_pending() acquires the subflow socket lock + for (;;) { + flags = 0; + if (test_and_clear_bit(MPTCP_PUSH_PENDING, &mptcp_sk(sk)->flags)) + flags |= MPTCP_PUSH_PENDING; + if (!flags) + break; + + /* the following actions acquire the subflow socket lock * * 1) can't be invoked in atomic scope * 2) must avoid ABBA deadlock with msk socket spinlock: the RX @@ -2959,13 +2960,21 @@ static void mptcp_release_cb(struct sock *sk) */
spin_unlock_bh(&sk->sk_lock.slock); - mptcp_push_pending(sk, 0); + if (flags & MPTCP_PUSH_PENDING) + __mptcp_push_pending(sk, 0); + + cond_resched(); spin_lock_bh(&sk->sk_lock.slock); } + + if (test_and_clear_bit(MPTCP_CLEAN_UNA, &mptcp_sk(sk)->flags)) + __mptcp_clean_una(sk); if (test_and_clear_bit(MPTCP_ERROR_REPORT, &mptcp_sk(sk)->flags)) __mptcp_error_report(sk);
- /* clear any wmem reservation and errors */ + /* push_pending may touch wmem_reserved, ensure we do the cleanup + * later + */ __mptcp_update_wmem(sk); __mptcp_update_rmem(sk);