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Subject[PATCH tip/core/rcu 55/88] rcu: Eliminate the unused __rcu_is_watching() function
Date
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 <mingo@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
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
@@ -1139,22 +1139,11 @@ void rcu_nmi_exit(void)
}

/**
- * __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;
}
--
2.5.2
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