#if defined(CONFIG_TREE_RCU) || defined(CONFIG_TREE_PREEMPT_RCU)
extern void rcutorture_record_test_transition(void);
extern void rcutorture_record_progress(unsigned long vernum);
+extern void do_trace_rcu_torture_read(char *rcutorturename,
+ struct rcu_head *rhp);
#else
static inline void rcutorture_record_test_transition(void)
{
static inline void rcutorture_record_progress(unsigned long vernum)
{
}
+#ifdef CONFIG_RCU_TRACE
+extern void do_trace_rcu_torture_read(char *rcutorturename,
+ struct rcu_head *rhp);
+#else
+#define do_trace_rcu_torture_read(rcutorturename, rhp) do { } while (0)
+#endif
#endif
#define UINT_CMP_GE(a, b) (UINT_MAX / 2 >= (a) - (b))
extern void rcu_bh_qs(int cpu);
extern void rcu_check_callbacks(int cpu, int user);
struct notifier_block;
-
-#ifdef CONFIG_NO_HZ
-
-extern void rcu_enter_nohz(void);
-extern void rcu_exit_nohz(void);
-
-#else /* #ifdef CONFIG_NO_HZ */
-
-static inline void rcu_enter_nohz(void)
-{
-}
-
-static inline void rcu_exit_nohz(void)
-{
-}
-
-#endif /* #else #ifdef CONFIG_NO_HZ */
+extern void rcu_idle_enter(void);
+extern void rcu_idle_exit(void);
+extern void rcu_irq_enter(void);
+extern void rcu_irq_exit(void);
/*
* Infrastructure to implement the synchronize_() primitives in
#ifdef CONFIG_DEBUG_LOCK_ALLOC
-extern struct lockdep_map rcu_lock_map;
-# define rcu_read_acquire() \
- lock_acquire(&rcu_lock_map, 0, 0, 2, 1, NULL, _THIS_IP_)
-# define rcu_read_release() lock_release(&rcu_lock_map, 1, _THIS_IP_)
+#ifdef CONFIG_PROVE_RCU
+extern int rcu_is_cpu_idle(void);
+#else /* !CONFIG_PROVE_RCU */
+static inline int rcu_is_cpu_idle(void)
+{
+ return 0;
+}
+#endif /* else !CONFIG_PROVE_RCU */
-extern struct lockdep_map rcu_bh_lock_map;
-# define rcu_read_acquire_bh() \
- lock_acquire(&rcu_bh_lock_map, 0, 0, 2, 1, NULL, _THIS_IP_)
-# define rcu_read_release_bh() lock_release(&rcu_bh_lock_map, 1, _THIS_IP_)
+static inline void rcu_lock_acquire(struct lockdep_map *map)
+{
+ WARN_ON_ONCE(rcu_is_cpu_idle());
+ lock_acquire(map, 0, 0, 2, 1, NULL, _THIS_IP_);
+}
-extern struct lockdep_map rcu_sched_lock_map;
-# define rcu_read_acquire_sched() \
- lock_acquire(&rcu_sched_lock_map, 0, 0, 2, 1, NULL, _THIS_IP_)
-# define rcu_read_release_sched() \
- lock_release(&rcu_sched_lock_map, 1, _THIS_IP_)
+static inline void rcu_lock_release(struct lockdep_map *map)
+{
+ WARN_ON_ONCE(rcu_is_cpu_idle());
+ lock_release(map, 1, _THIS_IP_);
+}
+extern struct lockdep_map rcu_lock_map;
+extern struct lockdep_map rcu_bh_lock_map;
+extern struct lockdep_map rcu_sched_lock_map;
extern int debug_lockdep_rcu_enabled(void);
/**
*
* Checks debug_lockdep_rcu_enabled() to prevent false positives during boot
* and while lockdep is disabled.
+ *
+ * Note that rcu_read_lock() and the matching rcu_read_unlock() must
+ * occur in the same context, for example, it is illegal to invoke
+ * rcu_read_unlock() in process context if the matching rcu_read_lock()
+ * was invoked from within an irq handler.
*/
static inline int rcu_read_lock_held(void)
{
if (!debug_lockdep_rcu_enabled())
return 1;
+ if (rcu_is_cpu_idle())
+ return 0;
return lock_is_held(&rcu_lock_map);
}
*
* Check debug_lockdep_rcu_enabled() to prevent false positives during boot
* and while lockdep is disabled.
+ *
+ * Note that if the CPU is in the idle loop from an RCU point of
+ * view (ie: that we are in the section between rcu_idle_enter() and
+ * rcu_idle_exit()) then rcu_read_lock_held() returns false even if the CPU
+ * did an rcu_read_lock(). The reason for this is that RCU ignores CPUs
+ * that are in such a section, considering these as in extended quiescent
+ * state, so such a CPU is effectively never in an RCU read-side critical
+ * section regardless of what RCU primitives it invokes. This state of
+ * affairs is required --- we need to keep an RCU-free window in idle
+ * where the CPU may possibly enter into low power mode. This way we can
+ * notice an extended quiescent state to other CPUs that started a grace
+ * period. Otherwise we would delay any grace period as long as we run in
+ * the idle task.
*/
#ifdef CONFIG_PREEMPT_COUNT
static inline int rcu_read_lock_sched_held(void)
if (!debug_lockdep_rcu_enabled())
return 1;
+ if (rcu_is_cpu_idle())
+ return 0;
if (debug_locks)
lockdep_opinion = lock_is_held(&rcu_sched_lock_map);
return lockdep_opinion || preempt_count() != 0 || irqs_disabled();
#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
-# define rcu_read_acquire() do { } while (0)
-# define rcu_read_release() do { } while (0)
-# define rcu_read_acquire_bh() do { } while (0)
-# define rcu_read_release_bh() do { } while (0)
-# define rcu_read_acquire_sched() do { } while (0)
-# define rcu_read_release_sched() do { } while (0)
+# define rcu_lock_acquire(a) do { } while (0)
+# define rcu_lock_release(a) do { } while (0)
static inline int rcu_read_lock_held(void)
{
{
__rcu_read_lock();
__acquire(RCU);
- rcu_read_acquire();
+ rcu_lock_acquire(&rcu_lock_map);
}
/*
*/
static inline void rcu_read_unlock(void)
{
- rcu_read_release();
+ rcu_lock_release(&rcu_lock_map);
__release(RCU);
__rcu_read_unlock();
}
* critical sections in interrupt context can use just rcu_read_lock(),
* though this should at least be commented to avoid confusing people
* reading the code.
+ *
+ * Note that rcu_read_lock_bh() and the matching rcu_read_unlock_bh()
+ * must occur in the same context, for example, it is illegal to invoke
+ * rcu_read_unlock_bh() from one task if the matching rcu_read_lock_bh()
+ * was invoked from some other task.
*/
static inline void rcu_read_lock_bh(void)
{
local_bh_disable();
__acquire(RCU_BH);
- rcu_read_acquire_bh();
+ rcu_lock_acquire(&rcu_bh_lock_map);
}
/*
*/
static inline void rcu_read_unlock_bh(void)
{
- rcu_read_release_bh();
+ rcu_lock_release(&rcu_bh_lock_map);
__release(RCU_BH);
local_bh_enable();
}
* are being done using call_rcu_sched() or synchronize_rcu_sched().
* Read-side critical sections can also be introduced by anything that
* disables preemption, including local_irq_disable() and friends.
+ *
+ * Note that rcu_read_lock_sched() and the matching rcu_read_unlock_sched()
+ * must occur in the same context, for example, it is illegal to invoke
+ * rcu_read_unlock_sched() from process context if the matching
+ * rcu_read_lock_sched() was invoked from an NMI handler.
*/
static inline void rcu_read_lock_sched(void)
{
preempt_disable();
__acquire(RCU_SCHED);
- rcu_read_acquire_sched();
+ rcu_lock_acquire(&rcu_sched_lock_map);
}
/* Used by lockdep and tracing: cannot be traced, cannot call lockdep. */
*/
static inline void rcu_read_unlock_sched(void)
{
- rcu_read_release_sched();
+ rcu_lock_release(&rcu_sched_lock_map);
__release(RCU_SCHED);
preempt_enable();
}
/* See the kfree_rcu() header comment. */
BUILD_BUG_ON(!__is_kfree_rcu_offset(offset));
- call_rcu(head, (rcu_callback)offset);
+ kfree_call_rcu(head, (rcu_callback)offset);
}
/**
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