@@ -46,7 +46,9 @@ static struct percpu_counter mptcp_sockets_allocated ____cacheline_aligned_in_sm
static void __mptcp_destroy_sock(struct sock *sk);
static void mptcp_check_send_data_fin(struct sock *sk);
-DEFINE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions);
+DEFINE_PER_CPU(struct mptcp_delegated_action, mptcp_delegated_actions) = {
+ .bh_lock = INIT_LOCAL_LOCK(bh_lock),
+};
static struct net_device *mptcp_napi_dev;
/* Returns end sequence number of the receiver's advertised window */
@@ -479,6 +479,7 @@ mptcp_subflow_rsk(const struct request_sock *rsk)
struct mptcp_delegated_action {
struct napi_struct napi;
+ local_lock_t bh_lock;
struct list_head head;
};
@@ -670,9 +671,11 @@ static inline void mptcp_subflow_delegate(struct mptcp_subflow_context *subflow,
if (WARN_ON_ONCE(!list_empty(&subflow->delegated_node)))
return;
+ local_lock_nested_bh(&mptcp_delegated_actions.bh_lock);
delegated = this_cpu_ptr(&mptcp_delegated_actions);
schedule = list_empty(&delegated->head);
list_add_tail(&subflow->delegated_node, &delegated->head);
+ local_unlock_nested_bh(&mptcp_delegated_actions.bh_lock);
sock_hold(mptcp_subflow_tcp_sock(subflow));
if (schedule)
napi_schedule(&delegated->napi);
@@ -684,11 +687,15 @@ mptcp_subflow_delegated_next(struct mptcp_delegated_action *delegated)
{
struct mptcp_subflow_context *ret;
- if (list_empty(&delegated->head))
+ local_lock_nested_bh(&mptcp_delegated_actions.bh_lock);
+ if (list_empty(&delegated->head)) {
+ local_unlock_nested_bh(&mptcp_delegated_actions.bh_lock);
return NULL;
+ }
ret = list_first_entry(&delegated->head, struct mptcp_subflow_context, delegated_node);
list_del_init(&ret->delegated_node);
+ local_unlock_nested_bh(&mptcp_delegated_actions.bh_lock);
return ret;
}
mptcp_delegated_actions is a per-CPU variable and relies on disabled BH for its locking. Without per-CPU locking in local_bh_disable() on PREEMPT_RT this data structure requires explicit locking. Add a local_lock_t to the data structure and use local_lock_nested_bh() for locking. This change adds only lockdep coverage and does not alter the functional behaviour for !PREEMPT_RT. Cc: Matthieu Baerts <matttbe@kernel.org> Cc: Mat Martineau <martineau@kernel.org> Cc: Geliang Tang <geliang@kernel.org> Cc: mptcp@lists.linux.dev Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- net/mptcp/protocol.c | 4 +++- net/mptcp/protocol.h | 9 ++++++++- 2 files changed, 11 insertions(+), 2 deletions(-)