Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull RCU updates from Ingo Molnar:
 "The sole purpose of these changes is to shrink and simplify the RCU
  code base, which has suffered from creeping bloat over the past couple
  of years. The end result is a net removal of ~2700 lines of code:

     79 files changed, 1496 insertions(+), 4211 deletions(-)

  Plus there's a marked reduction in the Kconfig space complexity as
  well, here's the number of matches on 'grep RCU' in the .config:

                               before       after

     x86-defconfig                 17          15
     x86-allmodconfig              33          20"

* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (86 commits)
  rcu: Remove RCU CPU stall warnings from Tiny RCU
  rcu: Remove event tracing from Tiny RCU
  rcu: Move RCU debug Kconfig options to kernel/rcu
  rcu: Move RCU non-debug Kconfig options to kernel/rcu
  rcu: Eliminate NOCBs CPU-state Kconfig options
  rcu: Remove debugfs tracing
  srcu: Remove Classic SRCU
  srcu: Fix rcutorture-statistics typo
  rcu: Remove SPARSE_RCU_POINTER Kconfig option
  rcu: Remove the now-obsolete PROVE_RCU_REPEATEDLY Kconfig option
  rcu: Remove typecheck() from RCU locking wrapper functions
  rcu: Remove #ifdef moving rcu_end_inkernel_boot from rcupdate.h
  rcu: Remove nohz_full full-system-idle state machine
  rcu: Remove the RCU_KTHREAD_PRIO Kconfig option
  rcu: Remove *_SLOW_* Kconfig options
  srcu: Use rnp->lock wrappers to replace explicit memory barriers
  rcu: Move rnp->lock wrappers for SRCU use
  rcu: Convert rnp->lock wrappers to macros for SRCU use
  rcu: Refactor #includes from include/linux/rcupdate.h
  bcm47xx: Fix build regression
  ...

1 files changed, 277 insertions, 0 deletions

diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
index 73e16ec4054b..808b8c85f626 100644
--- a/kernel/rcu/rcu.h
+++ b/kernel/rcu/rcu.h
@@ -212,6 +212,18 @@ int rcu_jiffies_till_stall_check(void);
  */
 #define TPS(x)  tracepoint_string(x)
 
+/*
+ * Dump the ftrace buffer, but only one time per callsite per boot.
+ */
+#define rcu_ftrace_dump(oops_dump_mode) \
+do { \
+	static atomic_t ___rfd_beenhere = ATOMIC_INIT(0); \
+	\
+	if (!atomic_read(&___rfd_beenhere) && \
+	    !atomic_xchg(&___rfd_beenhere, 1)) \
+		ftrace_dump(oops_dump_mode); \
+} while (0)
+
 void rcu_early_boot_tests(void);
 void rcu_test_sync_prims(void);
 
@@ -291,6 +303,271 @@ static inline void rcu_init_levelspread(int *levelspread, const int *levelcnt)
 	     cpu <= rnp->grphi; \
 	     cpu = cpumask_next((cpu), cpu_possible_mask))
 
+/*
+ * Wrappers for the rcu_node::lock acquire and release.
+ *
+ * Because the rcu_nodes form a tree, the tree traversal locking will observe
+ * different lock values, this in turn means that an UNLOCK of one level
+ * followed by a LOCK of another level does not imply a full memory barrier;
+ * and most importantly transitivity is lost.
+ *
+ * In order to restore full ordering between tree levels, augment the regular
+ * lock acquire functions with smp_mb__after_unlock_lock().
+ *
+ * As ->lock of struct rcu_node is a __private field, therefore one should use
+ * these wrappers rather than directly call raw_spin_{lock,unlock}* on ->lock.
+ */
+#define raw_spin_lock_rcu_node(p)					\
+do {									\
+	raw_spin_lock(&ACCESS_PRIVATE(p, lock));			\
+	smp_mb__after_unlock_lock();					\
+} while (0)
+
+#define raw_spin_unlock_rcu_node(p) raw_spin_unlock(&ACCESS_PRIVATE(p, lock))
+
+#define raw_spin_lock_irq_rcu_node(p)					\
+do {									\
+	raw_spin_lock_irq(&ACCESS_PRIVATE(p, lock));			\
+	smp_mb__after_unlock_lock();					\
+} while (0)
+
+#define raw_spin_unlock_irq_rcu_node(p)					\
+	raw_spin_unlock_irq(&ACCESS_PRIVATE(p, lock))
+
+#define raw_spin_lock_irqsave_rcu_node(p, flags)			\
+do {									\
+	raw_spin_lock_irqsave(&ACCESS_PRIVATE(p, lock), flags);	\
+	smp_mb__after_unlock_lock();					\
+} while (0)
+
+#define raw_spin_unlock_irqrestore_rcu_node(p, flags)			\
+	raw_spin_unlock_irqrestore(&ACCESS_PRIVATE(p, lock), flags)	\
+
+#define raw_spin_trylock_rcu_node(p)					\
+({									\
+	bool ___locked = raw_spin_trylock(&ACCESS_PRIVATE(p, lock));	\
+									\
+	if (___locked)							\
+		smp_mb__after_unlock_lock();				\
+	___locked;							\
+})
+
 #endif /* #if defined(SRCU) || !defined(TINY_RCU) */
 
+#ifdef CONFIG_TINY_RCU
+/* Tiny RCU doesn't expedite, as its purpose in life is instead to be tiny. */
+static inline bool rcu_gp_is_normal(void)  /* Internal RCU use. */
+{
+	return true;
+}
+static inline bool rcu_gp_is_expedited(void)  /* Internal RCU use. */
+{
+	return false;
+}
+
+static inline void rcu_expedite_gp(void)
+{
+}
+
+static inline void rcu_unexpedite_gp(void)
+{
+}
+#else /* #ifdef CONFIG_TINY_RCU */
+bool rcu_gp_is_normal(void);     /* Internal RCU use. */
+bool rcu_gp_is_expedited(void);  /* Internal RCU use. */
+void rcu_expedite_gp(void);
+void rcu_unexpedite_gp(void);
+void rcupdate_announce_bootup_oddness(void);
+#endif /* #else #ifdef CONFIG_TINY_RCU */
+
+#define RCU_SCHEDULER_INACTIVE	0
+#define RCU_SCHEDULER_INIT	1
+#define RCU_SCHEDULER_RUNNING	2
+
+#ifdef CONFIG_TINY_RCU
+static inline void rcu_request_urgent_qs_task(struct task_struct *t) { }
+#else /* #ifdef CONFIG_TINY_RCU */
+void rcu_request_urgent_qs_task(struct task_struct *t);
+#endif /* #else #ifdef CONFIG_TINY_RCU */
+
+enum rcutorture_type {
+	RCU_FLAVOR,
+	RCU_BH_FLAVOR,
+	RCU_SCHED_FLAVOR,
+	RCU_TASKS_FLAVOR,
+	SRCU_FLAVOR,
+	INVALID_RCU_FLAVOR
+};
+
+#if defined(CONFIG_TREE_RCU) || defined(CONFIG_PREEMPT_RCU)
+void rcutorture_get_gp_data(enum rcutorture_type test_type, int *flags,
+			    unsigned long *gpnum, unsigned long *completed);
+void rcutorture_record_test_transition(void);
+void rcutorture_record_progress(unsigned long vernum);
+void do_trace_rcu_torture_read(const char *rcutorturename,
+			       struct rcu_head *rhp,
+			       unsigned long secs,
+			       unsigned long c_old,
+			       unsigned long c);
+#else
+static inline void rcutorture_get_gp_data(enum rcutorture_type test_type,
+					  int *flags,
+					  unsigned long *gpnum,
+					  unsigned long *completed)
+{
+	*flags = 0;
+	*gpnum = 0;
+	*completed = 0;
+}
+static inline void rcutorture_record_test_transition(void)
+{
+}
+static inline void rcutorture_record_progress(unsigned long vernum)
+{
+}
+#ifdef CONFIG_RCU_TRACE
+void do_trace_rcu_torture_read(const char *rcutorturename,
+			       struct rcu_head *rhp,
+			       unsigned long secs,
+			       unsigned long c_old,
+			       unsigned long c);
+#else
+#define do_trace_rcu_torture_read(rcutorturename, rhp, secs, c_old, c) \
+	do { } while (0)
+#endif
+#endif
+
+#ifdef CONFIG_TINY_SRCU
+
+static inline void srcutorture_get_gp_data(enum rcutorture_type test_type,
+					   struct srcu_struct *sp, int *flags,
+					   unsigned long *gpnum,
+					   unsigned long *completed)
+{
+	if (test_type != SRCU_FLAVOR)
+		return;
+	*flags = 0;
+	*completed = sp->srcu_idx;
+	*gpnum = *completed;
+}
+
+#elif defined(CONFIG_TREE_SRCU)
+
+void srcutorture_get_gp_data(enum rcutorture_type test_type,
+			     struct srcu_struct *sp, int *flags,
+			     unsigned long *gpnum, unsigned long *completed);
+
+#endif
+
+#ifdef CONFIG_TINY_RCU
+
+/*
+ * Return the number of grace periods started.
+ */
+static inline unsigned long rcu_batches_started(void)
+{
+	return 0;
+}
+
+/*
+ * Return the number of bottom-half grace periods started.
+ */
+static inline unsigned long rcu_batches_started_bh(void)
+{
+	return 0;
+}
+
+/*
+ * Return the number of sched grace periods started.
+ */
+static inline unsigned long rcu_batches_started_sched(void)
+{
+	return 0;
+}
+
+/*
+ * Return the number of grace periods completed.
+ */
+static inline unsigned long rcu_batches_completed(void)
+{
+	return 0;
+}
+
+/*
+ * Return the number of bottom-half grace periods completed.
+ */
+static inline unsigned long rcu_batches_completed_bh(void)
+{
+	return 0;
+}
+
+/*
+ * Return the number of sched grace periods completed.
+ */
+static inline unsigned long rcu_batches_completed_sched(void)
+{
+	return 0;
+}
+
+/*
+ * Return the number of expedited grace periods completed.
+ */
+static inline unsigned long rcu_exp_batches_completed(void)
+{
+	return 0;
+}
+
+/*
+ * Return the number of expedited sched grace periods completed.
+ */
+static inline unsigned long rcu_exp_batches_completed_sched(void)
+{
+	return 0;
+}
+
+static inline unsigned long srcu_batches_completed(struct srcu_struct *sp)
+{
+	return 0;
+}
+
+static inline void rcu_force_quiescent_state(void)
+{
+}
+
+static inline void rcu_bh_force_quiescent_state(void)
+{
+}
+
+static inline void rcu_sched_force_quiescent_state(void)
+{
+}
+
+static inline void show_rcu_gp_kthreads(void)
+{
+}
+
+#else /* #ifdef CONFIG_TINY_RCU */
+extern unsigned long rcutorture_testseq;
+extern unsigned long rcutorture_vernum;
+unsigned long rcu_batches_started(void);
+unsigned long rcu_batches_started_bh(void);
+unsigned long rcu_batches_started_sched(void);
+unsigned long rcu_batches_completed(void);
+unsigned long rcu_batches_completed_bh(void);
+unsigned long rcu_batches_completed_sched(void);
+unsigned long rcu_exp_batches_completed(void);
+unsigned long rcu_exp_batches_completed_sched(void);
+unsigned long srcu_batches_completed(struct srcu_struct *sp);
+void show_rcu_gp_kthreads(void);
+void rcu_force_quiescent_state(void);
+void rcu_bh_force_quiescent_state(void);
+void rcu_sched_force_quiescent_state(void);
+#endif /* #else #ifdef CONFIG_TINY_RCU */
+
+#ifdef CONFIG_RCU_NOCB_CPU
+bool rcu_is_nocb_cpu(int cpu);
+#else
+static inline bool rcu_is_nocb_cpu(int cpu) { return false; }
+#endif
+
 #endif /* __LINUX_RCU_H */