Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input

[cascardo/linux.git] / include / linux / rcupdate.h

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 95e0615..3ebd0b7 100644 (file)
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -1,5 +1,5 @@
 /*
- * Read-Copy Update mechanism for mutual exclusion 
+ * Read-Copy Update mechanism for mutual exclusion
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -18,7 +18,7 @@
  * Copyright IBM Corporation, 2001
  *
  * Author: Dipankar Sarma <dipankar@in.ibm.com>
- * 
+ *
  * Based on the original work by Paul McKenney <paulmck@us.ibm.com>
  * and inputs from Rusty Russell, Andrea Arcangeli and Andi Kleen.
  * Papers:
@@ -26,7 +26,7 @@
  * http://lse.sourceforge.net/locking/rclock_OLS.2001.05.01c.sc.pdf (OLS2001)
  *
  * For detailed explanation of Read-Copy Update mechanism see -
- *             http://lse.sourceforge.net/locking/rcupdate.html
+ *             http://lse.sourceforge.net/locking/rcupdate.html
  *
  */
 
@@ -52,8 +52,13 @@ struct rcu_head {
 };
 
 /* Exported common interfaces */
+#ifdef CONFIG_TREE_PREEMPT_RCU
 extern void synchronize_rcu(void);
+#else /* #ifdef CONFIG_TREE_PREEMPT_RCU */
+#define synchronize_rcu synchronize_sched
+#endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */
 extern void synchronize_rcu_bh(void);
+extern void synchronize_sched(void);
 extern void rcu_barrier(void);
 extern void rcu_barrier_bh(void);
 extern void rcu_barrier_sched(void);
@@ -72,7 +77,7 @@ extern int rcu_scheduler_active;
 #error "Unknown RCU implementation specified to kernel configuration"
 #endif
 
-#define RCU_HEAD_INIT  { .next = NULL, .func = NULL }
+#define RCU_HEAD_INIT  { .next = NULL, .func = NULL }
 #define RCU_HEAD(head) struct rcu_head head = RCU_HEAD_INIT
 #define INIT_RCU_HEAD(ptr) do { \
        (ptr)->next = NULL; (ptr)->func = NULL; \
@@ -124,12 +129,6 @@ static inline void rcu_read_lock(void)
        rcu_read_acquire();
 }
 
-/**
- * rcu_read_unlock - marks the end of an RCU read-side critical section.
- *
- * See rcu_read_lock() for more information.
- */
-
 /*
  * So where is rcu_write_lock()?  It does not exist, as there is no
  * way for writers to lock out RCU readers.  This is a feature, not
@@ -139,6 +138,12 @@ static inline void rcu_read_lock(void)
  * used as well.  RCU does not care how the writers keep out of each
  * others' way, as long as they do so.
  */
+
+/**
+ * rcu_read_unlock - marks the end of an RCU read-side critical section.
+ *
+ * See rcu_read_lock() for more information.
+ */
 static inline void rcu_read_unlock(void)
 {
        rcu_read_release();
@@ -191,6 +196,8 @@ static inline void rcu_read_lock_sched(void)
        __acquire(RCU_SCHED);
        rcu_read_acquire();
 }
+
+/* Used by lockdep and tracing: cannot be traced, cannot call lockdep. */
 static inline notrace void rcu_read_lock_sched_notrace(void)
 {
        preempt_disable_notrace();
@@ -208,6 +215,8 @@ static inline void rcu_read_unlock_sched(void)
        __release(RCU_SCHED);
        preempt_enable();
 }
+
+/* Used by lockdep and tracing: cannot be traced, cannot call lockdep. */
 static inline notrace void rcu_read_unlock_sched_notrace(void)
 {
        __release(RCU_SCHED);
@@ -261,24 +270,6 @@ struct rcu_synchronize {
 
 extern void wakeme_after_rcu(struct rcu_head  *head);
 
-/**
- * synchronize_sched - block until all CPUs have exited any non-preemptive
- * kernel code sequences.
- *
- * This means that all preempt_disable code sequences, including NMI and
- * hardware-interrupt handlers, in progress on entry will have completed
- * before this primitive returns.  However, this does not guarantee that
- * softirq handlers will have completed, since in some kernels, these
- * handlers can run in process context, and can block.
- *
- * This primitive provides the guarantees made by the (now removed)
- * synchronize_kernel() API.  In contrast, synchronize_rcu() only
- * guarantees that rcu_read_lock() sections will have completed.
- * In "classic RCU", these two guarantees happen to be one and
- * the same, but can differ in realtime RCU implementations.
- */
-#define synchronize_sched() __synchronize_sched()
-
 /**
  * call_rcu - Queue an RCU callback for invocation after a grace period.
  * @head: structure to be used for queueing the RCU updates.