From: Paolo Abeni pabeni@redhat.com
Such field is there to avoid acquiring the data lock in a few spots, but it adds complexity to the already non trivial locking schema.
All the relevant call sites (mptcp-level re-injection, set socket options), are slow-path, drop such field in favor of 'cb_flags', adding the relevant locking.
This patch could be seen as an improvement, instead of a fix. But it simplifies the next patch. The 'Fixes' tag has been added to help having this series backported to stable.
Fixes: e9d09baca676 ("mptcp: avoid atomic bit manipulation when possible") Cc: stable@vger.kernel.org Signed-off-by: Paolo Abeni pabeni@redhat.com Reviewed-by: Mat Martineau martineau@kernel.org Signed-off-by: Matthieu Baerts (NGI0) matttbe@kernel.org --- net/mptcp/protocol.c | 12 ++++++------ net/mptcp/protocol.h | 1 - 2 files changed, 6 insertions(+), 7 deletions(-)
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 028e8b473626..2111819016af 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1505,8 +1505,11 @@ static void mptcp_update_post_push(struct mptcp_sock *msk,
void mptcp_check_and_set_pending(struct sock *sk) { - if (mptcp_send_head(sk)) - mptcp_sk(sk)->push_pending |= BIT(MPTCP_PUSH_PENDING); + if (mptcp_send_head(sk)) { + mptcp_data_lock(sk); + mptcp_sk(sk)->cb_flags |= BIT(MPTCP_PUSH_PENDING); + mptcp_data_unlock(sk); + } }
static int __subflow_push_pending(struct sock *sk, struct sock *ssk, @@ -3142,7 +3145,6 @@ static int mptcp_disconnect(struct sock *sk, int flags) mptcp_destroy_common(msk, MPTCP_CF_FASTCLOSE); WRITE_ONCE(msk->flags, 0); msk->cb_flags = 0; - msk->push_pending = 0; msk->recovery = false; msk->can_ack = false; msk->fully_established = false; @@ -3330,8 +3332,7 @@ static void mptcp_release_cb(struct sock *sk) struct mptcp_sock *msk = mptcp_sk(sk);
for (;;) { - unsigned long flags = (msk->cb_flags & MPTCP_FLAGS_PROCESS_CTX_NEED) | - msk->push_pending; + unsigned long flags = (msk->cb_flags & MPTCP_FLAGS_PROCESS_CTX_NEED); struct list_head join_list;
if (!flags) @@ -3347,7 +3348,6 @@ static void mptcp_release_cb(struct sock *sk) * datapath acquires the msk socket spinlock while helding * the subflow socket lock */ - msk->push_pending = 0; msk->cb_flags &= ~flags; spin_unlock_bh(&sk->sk_lock.slock);
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index 3517f2d24a22..b905f1868298 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -286,7 +286,6 @@ struct mptcp_sock { int rmem_released; unsigned long flags; unsigned long cb_flags; - unsigned long push_pending; bool recovery; /* closing subflow write queue reinjected */ bool can_ack; bool fully_established;