From 791875d16e2f6e2e5b90328ccac643f512ac76c4 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 3 May 2017 11:06:05 -0700 Subject: [PATCH] rcu: Eliminate the unused __rcu_is_watching() function The __rcu_is_watching() function is currently not used, aside from to implement the rcu_is_watching() function. This commit therefore eliminates __rcu_is_watching(), which has the beneficial side-effect of shrinking include/linux/rcupdate.h a bit. Reported-by: Ingo Molnar Signed-off-by: Paul E. McKenney --- include/linux/rcupdate.h | 4 ---- include/linux/rcutiny.h | 11 ----------- kernel/rcu/tiny.c | 13 ------------- kernel/rcu/tree.c | 19 ++++--------------- 4 files changed, 4 insertions(+), 43 deletions(-) diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 415633076cb1..b4edfe0966c6 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -204,10 +204,6 @@ do { \ rcu_note_voluntary_context_switch(current); \ } while (0) -#if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) || defined(CONFIG_SMP) -bool __rcu_is_watching(void); -#endif /* #if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) || defined(CONFIG_SMP) */ - /* * Infrastructure to implement the synchronize_() primitives in * TREE_RCU and rcu_barrier_() primitives in TINY_RCU. diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index ade360e0d58c..5ed6934152a6 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -232,22 +232,11 @@ static inline void rcu_scheduler_starting(void) } #endif /* #else #if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_SRCU) */ -#if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) - -static inline bool rcu_is_watching(void) -{ - return __rcu_is_watching(); -} - -#else /* defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) */ - static inline bool rcu_is_watching(void) { return true; } -#endif /* #else defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) */ - static inline void rcu_request_urgent_qs_task(struct task_struct *t) { } diff --git a/kernel/rcu/tiny.c b/kernel/rcu/tiny.c index e5385731e391..2306cab2195d 100644 --- a/kernel/rcu/tiny.c +++ b/kernel/rcu/tiny.c @@ -59,19 +59,6 @@ void rcu_barrier_sched(void) } EXPORT_SYMBOL(rcu_barrier_sched); -#if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) - -/* - * Test whether RCU thinks that the current CPU is idle. - */ -bool notrace __rcu_is_watching(void) -{ - return true; -} -EXPORT_SYMBOL(__rcu_is_watching); - -#endif /* defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) */ - /* * Helper function for rcu_sched_qs() and rcu_bh_qs(). * Also irqs are disabled to avoid confusion due to interrupt handlers diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 5ebc830297c1..61a97164abcc 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1138,23 +1138,12 @@ void rcu_nmi_exit(void) rcu_dynticks_eqs_enter(); } -/** - * __rcu_is_watching - are RCU read-side critical sections safe? - * - * Return true if RCU is watching the running CPU, which means that - * this CPU can safely enter RCU read-side critical sections. Unlike - * rcu_is_watching(), the caller of __rcu_is_watching() must have at - * least disabled preemption. - */ -bool notrace __rcu_is_watching(void) -{ - return !rcu_dynticks_curr_cpu_in_eqs(); -} - /** * rcu_is_watching - see if RCU thinks that the current CPU is idle * - * If the current CPU is in its idle loop and is neither in an interrupt + * Return true if RCU is watching the running CPU, which means that this + * CPU can safely enter RCU read-side critical sections. In other words, + * if the current CPU is in its idle loop and is neither in an interrupt * or NMI handler, return true. */ bool notrace rcu_is_watching(void) @@ -1162,7 +1151,7 @@ bool notrace rcu_is_watching(void) bool ret; preempt_disable_notrace(); - ret = __rcu_is_watching(); + ret = !rcu_dynticks_curr_cpu_in_eqs(); preempt_enable_notrace(); return ret; } -- 2.20.1