rcu: Consistent rcu_is_watching() naming

The old rcu_is_cpu_idle() function is just __rcu_is_watching() with
preemption disabled.  This commit therefore renames rcu_is_cpu_idle()
to rcu_is_watching.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index a53a21a..39cbb88 100644 (file)
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -262,7 +262,7 @@ static inline void rcu_user_hooks_switch(struct task_struct *prev,
        } while (0)
 
 #if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) || defined(CONFIG_SMP)
-extern int rcu_is_cpu_idle(void);
+extern bool __rcu_is_watching(void);
 #endif /* #if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) || defined(CONFIG_SMP) */
 
 /*
@@ -351,7 +351,7 @@ static inline int rcu_read_lock_held(void)
 {
        if (!debug_lockdep_rcu_enabled())
                return 1;
-       if (rcu_is_cpu_idle())
+       if (!rcu_is_watching())
                return 0;
        if (!rcu_lockdep_current_cpu_online())
                return 0;
@@ -402,7 +402,7 @@ static inline int rcu_read_lock_sched_held(void)
 
        if (!debug_lockdep_rcu_enabled())
                return 1;
-       if (rcu_is_cpu_idle())
+       if (!rcu_is_watching())
                return 0;
        if (!rcu_lockdep_current_cpu_online())
                return 0;
@@ -771,7 +771,7 @@ static inline void rcu_read_lock(void)
        __rcu_read_lock();
        __acquire(RCU);
        rcu_lock_acquire(&rcu_lock_map);
-       rcu_lockdep_assert(!rcu_is_cpu_idle(),
+       rcu_lockdep_assert(rcu_is_watching(),
                           "rcu_read_lock() used illegally while idle");
 }
 
@@ -792,7 +792,7 @@ static inline void rcu_read_lock(void)
  */
 static inline void rcu_read_unlock(void)
 {
-       rcu_lockdep_assert(!rcu_is_cpu_idle(),
+       rcu_lockdep_assert(rcu_is_watching(),
                           "rcu_read_unlock() used illegally while idle");
        rcu_lock_release(&rcu_lock_map);
        __release(RCU);
@@ -821,7 +821,7 @@ static inline void rcu_read_lock_bh(void)
        local_bh_disable();
        __acquire(RCU_BH);
        rcu_lock_acquire(&rcu_bh_lock_map);
-       rcu_lockdep_assert(!rcu_is_cpu_idle(),
+       rcu_lockdep_assert(rcu_is_watching(),
                           "rcu_read_lock_bh() used illegally while idle");
 }
 
@@ -832,7 +832,7 @@ static inline void rcu_read_lock_bh(void)
  */
 static inline void rcu_read_unlock_bh(void)
 {
-       rcu_lockdep_assert(!rcu_is_cpu_idle(),
+       rcu_lockdep_assert(rcu_is_watching(),
                           "rcu_read_unlock_bh() used illegally while idle");
        rcu_lock_release(&rcu_bh_lock_map);
        __release(RCU_BH);
@@ -857,7 +857,7 @@ static inline void rcu_read_lock_sched(void)
        preempt_disable();
        __acquire(RCU_SCHED);
        rcu_lock_acquire(&rcu_sched_lock_map);
-       rcu_lockdep_assert(!rcu_is_cpu_idle(),
+       rcu_lockdep_assert(rcu_is_watching(),
                           "rcu_read_lock_sched() used illegally while idle");
 }
 
@@ -875,7 +875,7 @@ static inline notrace void rcu_read_lock_sched_notrace(void)
  */
 static inline void rcu_read_unlock_sched(void)
 {
-       rcu_lockdep_assert(!rcu_is_cpu_idle(),
+       rcu_lockdep_assert(rcu_is_watching(),
                           "rcu_read_unlock_sched() used illegally while idle");
        rcu_lock_release(&rcu_sched_lock_map);
        __release(RCU_SCHED);

diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h
index bee6659..09ebcbe 100644 (file)
--- a/include/linux/rcutiny.h
+++ b/include/linux/rcutiny.h
@@ -132,13 +132,21 @@ static inline void rcu_scheduler_starting(void)
 }
 #endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
 
-#ifdef CONFIG_RCU_TRACE
+#if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE)
 
-static inline bool __rcu_is_watching(void)
+static inline bool rcu_is_watching(void)
 {
-       return !rcu_is_cpu_idle();
+       return __rcu_is_watching();
 }
 
-#endif /* #ifdef CONFIG_RCU_TRACE */
+#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) */
 
 #endif /* __LINUX_RCUTINY_H */

diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h
index 293613d..4b9c815 100644 (file)
--- a/include/linux/rcutree.h
+++ b/include/linux/rcutree.h
@@ -90,6 +90,6 @@ extern void exit_rcu(void);
 extern void rcu_scheduler_starting(void);
 extern int rcu_scheduler_active __read_mostly;
 
-extern bool __rcu_is_watching(void);
+extern bool rcu_is_watching(void);
 
 #endif /* __LINUX_RCUTREE_H */

diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index e16c45b..4e8e14c 100644 (file)
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -4224,7 +4224,7 @@ void lockdep_rcu_suspicious(const char *file, const int line, const char *s)
        printk("\n%srcu_scheduler_active = %d, debug_locks = %d\n",
               !rcu_lockdep_current_cpu_online()
                        ? "RCU used illegally from offline CPU!\n"
-                       : rcu_is_cpu_idle()
+                       : !rcu_is_watching()
                                ? "RCU used illegally from idle CPU!\n"
                                : "",
               rcu_scheduler_active, debug_locks);
@@ -4247,7 +4247,7 @@ void lockdep_rcu_suspicious(const char *file, const int line, const char *s)
         * So complain bitterly if someone does call rcu_read_lock(),
         * rcu_read_lock_bh() and so on from extended quiescent states.
         */
-       if (rcu_is_cpu_idle())
+       if (!rcu_is_watching())
                printk("RCU used illegally from extended quiescent state!\n");
 
        lockdep_print_held_locks(curr);

diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
index b02a339..3b3c046 100644 (file)
--- a/kernel/rcupdate.c
+++ b/kernel/rcupdate.c
@@ -148,7 +148,7 @@ int rcu_read_lock_bh_held(void)
 {
        if (!debug_lockdep_rcu_enabled())
                return 1;
-       if (rcu_is_cpu_idle())
+       if (!rcu_is_watching())
                return 0;
        if (!rcu_lockdep_current_cpu_online())
                return 0;

diff --git a/kernel/rcutiny.c b/kernel/rcutiny.c
index b4bc618..0fa061d 100644 (file)
--- a/kernel/rcutiny.c
+++ b/kernel/rcutiny.c
@@ -179,11 +179,11 @@ EXPORT_SYMBOL_GPL(rcu_irq_enter);
 /*
  * Test whether RCU thinks that the current CPU is idle.
  */
-int rcu_is_cpu_idle(void)
+bool __rcu_is_watching(void)
 {
-       return !rcu_dynticks_nesting;
+       return rcu_dynticks_nesting;
 }
-EXPORT_SYMBOL(rcu_is_cpu_idle);
+EXPORT_SYMBOL(__rcu_is_watching);
 
 #endif /* defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) */
 

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 1b123e1..981d0c1 100644 (file)
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -655,34 +655,34 @@ void rcu_nmi_exit(void)
 }
 
 /**
- * rcu_is_cpu_idle - see if RCU thinks that the current CPU is idle
+ * __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 __rcu_is_watching(void)
+{
+       return atomic_read(this_cpu_ptr(&rcu_dynticks.dynticks)) & 0x1;
+}
+
+/**
+ * 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
  * or NMI handler, return true.
  */
-int rcu_is_cpu_idle(void)
+bool rcu_is_watching(void)
 {
        int ret;
 
        preempt_disable();
-       ret = (atomic_read(&__get_cpu_var(rcu_dynticks).dynticks) & 0x1) == 0;
+       ret = __rcu_is_watching();
        preempt_enable();
        return ret;
 }
-EXPORT_SYMBOL_GPL(rcu_is_cpu_idle);
-
-/**
- * __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_cpu_idle(), the caller of __rcu_is_watching() must have at
- * least disabled preemption.
- */
-bool __rcu_is_watching(void)
-{
-       return !!(atomic_read(this_cpu_ptr(&rcu_dynticks.dynticks)) & 0x1);
-}
+EXPORT_SYMBOL_GPL(rcu_is_watching);
 
 #if defined(CONFIG_PROVE_RCU) && defined(CONFIG_HOTPLUG_CPU)
 
@@ -2268,7 +2268,7 @@ static void __call_rcu_core(struct rcu_state *rsp, struct rcu_data *rdp,
         * If called from an extended quiescent state, invoke the RCU
         * core in order to force a re-evaluation of RCU's idleness.
         */
-       if (rcu_is_cpu_idle() && cpu_online(smp_processor_id()))
+       if (!rcu_is_watching() && cpu_online(smp_processor_id()))
                invoke_rcu_core();
 
        /* If interrupts were disabled or CPU offline, don't invoke RCU core. */