Ever since the kvfree_rcu() tracing moved out of the callback-enqueue path, rcutree_enqueue() no longer looks at the callback function pointer: By the time it is invoked, __call_rcu_common() has already stored the function into rhp->func, and the enqueue path only adds the rcu_head to the segmented callback list and emits tracepoints that do not take the function pointer.
Nevertheless, the function pointer is still threaded through call_rcu_core(), call_rcu_nocb(), and rcutree_enqueue(), forcing each level to carry a dead argument. Remove the parameter from all three functions, from the no-CBs stub, and from the corresponding declarations. Anything needing the callback function can still get it from rhp->func. No functional change. Signed-off-by: Joel Fernandes <[email protected]> --- kernel/rcu/tree.c | 10 +++++----- kernel/rcu/tree.h | 2 +- kernel/rcu/tree_nocb.h | 6 +++--- 3 files changed, 9 insertions(+), 9 deletions(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index ef553189ee24..f741654e80e1 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -3020,7 +3020,7 @@ static int __init rcu_spawn_core_kthreads(void) return 0; } -static void rcutree_enqueue(struct rcu_data *rdp, struct rcu_head *head, rcu_callback_t func) +static void rcutree_enqueue(struct rcu_data *rdp, struct rcu_head *head) { rcu_segcblist_enqueue(&rdp->cblist, head); trace_rcu_callback(rcu_state.name, head, @@ -3032,9 +3032,9 @@ static void rcutree_enqueue(struct rcu_data *rdp, struct rcu_head *head, rcu_cal * Handle any core-RCU processing required by a call_rcu() invocation. */ static void call_rcu_core(struct rcu_data *rdp, struct rcu_head *head, - rcu_callback_t func, unsigned long flags) + unsigned long flags) { - rcutree_enqueue(rdp, head, func); + rcutree_enqueue(rdp, head); /* * If called from an extended quiescent state, invoke the RCU * core in order to force a re-evaluation of RCU's idleness. @@ -3175,9 +3175,9 @@ __call_rcu_common(struct rcu_head *head, rcu_callback_t func, bool lazy_in) check_cb_ovld(rdp); if (unlikely(rcu_rdp_is_offloaded(rdp))) - call_rcu_nocb(rdp, head, func, flags, lazy); + call_rcu_nocb(rdp, head, flags, lazy); else - call_rcu_core(rdp, head, func, flags); + call_rcu_core(rdp, head, flags); local_irq_restore(flags); } diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index beb86e39909a..aaccc57e75b1 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -502,7 +502,7 @@ static bool wake_nocb_gp(struct rcu_data *rdp); static bool rcu_nocb_flush_bypass(struct rcu_data *rdp, struct rcu_head *rhp, unsigned long j, bool lazy); static void call_rcu_nocb(struct rcu_data *rdp, struct rcu_head *head, - rcu_callback_t func, unsigned long flags, bool lazy); + unsigned long flags, bool lazy); static void __maybe_unused __call_rcu_nocb_wake(struct rcu_data *rdp, bool was_empty, unsigned long flags); static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp, int level); diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h index c4a5b4662b3a..9e5757e6f875 100644 --- a/kernel/rcu/tree_nocb.h +++ b/kernel/rcu/tree_nocb.h @@ -603,13 +603,13 @@ static void __call_rcu_nocb_wake(struct rcu_data *rdp, bool was_alldone, } static void call_rcu_nocb(struct rcu_data *rdp, struct rcu_head *head, - rcu_callback_t func, unsigned long flags, bool lazy) + unsigned long flags, bool lazy) { bool was_alldone; if (!rcu_nocb_try_bypass(rdp, head, &was_alldone, flags, lazy)) { /* Not enqueued on bypass but locked, do regular enqueue */ - rcutree_enqueue(rdp, head, func); + rcutree_enqueue(rdp, head); __call_rcu_nocb_wake(rdp, was_alldone, flags); /* unlocks */ } } @@ -1666,7 +1666,7 @@ static bool rcu_nocb_flush_bypass(struct rcu_data *rdp, struct rcu_head *rhp, } static void call_rcu_nocb(struct rcu_data *rdp, struct rcu_head *head, - rcu_callback_t func, unsigned long flags, bool lazy) + unsigned long flags, bool lazy) { WARN_ON_ONCE(1); /* Should be dead code! */ } -- 2.34.1
