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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>
This commit is contained in:
Paul E. McKenney 2013-09-13 17:20:11 -07:00
parent f9ffc31ebd
commit 5c173eb8bc
7 changed files with 48 additions and 40 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
include/linux/rcupdate.h
View File

@ -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);

16
include/linux/rcutiny.h
View File

@ -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 */

2
include/linux/rcutree.h
View File

@ -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 */

4
kernel/lockdep.c
View File

@ -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);

2
kernel/rcupdate.c
View File

@ -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;

6
kernel/rcutiny.c
View File

@ -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) */

40
kernel/rcutree.c
View File

@ -654,36 +654,36 @@ void rcu_nmi_exit(void)
WARN_ON_ONCE(atomic_read(&rdtp->dynticks) & 0x1);
}
/**
* rcu_is_cpu_idle - 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)
{
int ret;
preempt_disable();
ret = (atomic_read(&__get_cpu_var(rcu_dynticks).dynticks) & 0x1) == 0;
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
* 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);
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.
*/
bool rcu_is_watching(void)
{
int ret;
preempt_disable();
ret = __rcu_is_watching();
preempt_enable();
return ret;
}
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. */