rcu: Introduce lockdep-based checking to RCU read-side primitives

[safe/jmp/linux-2.6] / kernel / rcupdate.c

diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
index f14f372..033cb55 100644 (file)
--- a/kernel/rcupdate.c
+++ b/kernel/rcupdate.c
@@ -19,7 +19,7 @@
  *
  * Authors: Dipankar Sarma <dipankar@in.ibm.com>
  *         Manfred Spraul <manfred@colorfullife.com>
- * 
+ *
  * Based on the original work by Paul McKenney <paulmck@us.ibm.com>
  * and inputs from Rusty Russell, Andrea Arcangeli and Andi Kleen.
  * Papers:
@@ -27,7 +27,7 @@
  * 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
  *
  */
 #include <linux/types.h>
@@ -45,16 +45,22 @@
 #include <linux/mutex.h>
 #include <linux/module.h>
 
-enum rcu_barrier {
-       RCU_BARRIER_STD,
-       RCU_BARRIER_BH,
-       RCU_BARRIER_SCHED,
-};
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+static struct lock_class_key rcu_lock_key;
+struct lockdep_map rcu_lock_map =
+       STATIC_LOCKDEP_MAP_INIT("rcu_read_lock", &rcu_lock_key);
+EXPORT_SYMBOL_GPL(rcu_lock_map);
+
+static struct lock_class_key rcu_bh_lock_key;
+struct lockdep_map rcu_bh_lock_map =
+       STATIC_LOCKDEP_MAP_INIT("rcu_read_lock_bh", &rcu_bh_lock_key);
+EXPORT_SYMBOL_GPL(rcu_bh_lock_map);
 
-static DEFINE_PER_CPU(struct rcu_head, rcu_barrier_head) = {NULL};
-static atomic_t rcu_barrier_cpu_count;
-static DEFINE_MUTEX(rcu_barrier_mutex);
-static struct completion rcu_barrier_completion;
+static struct lock_class_key rcu_sched_lock_key;
+struct lockdep_map rcu_sched_lock_map =
+       STATIC_LOCKDEP_MAP_INIT("rcu_read_lock_sched", &rcu_sched_lock_key);
+EXPORT_SYMBOL_GPL(rcu_sched_lock_map);
+#endif
 
 /*
  * Awaken the corresponding synchronize_rcu() instance now that a
@@ -67,102 +73,3 @@ void wakeme_after_rcu(struct rcu_head  *head)
        rcu = container_of(head, struct rcu_synchronize, head);
        complete(&rcu->completion);
 }
-
-/**
- * synchronize_rcu - wait until a grace period has elapsed.
- *
- * Control will return to the caller some time after a full grace
- * period has elapsed, in other words after all currently executing RCU
- * read-side critical sections have completed.  RCU read-side critical
- * sections are delimited by rcu_read_lock() and rcu_read_unlock(),
- * and may be nested.
- */
-synchronize_rcu_xxx(synchronize_rcu, call_rcu)
-EXPORT_SYMBOL_GPL(synchronize_rcu);
-
-static void rcu_barrier_callback(struct rcu_head *notused)
-{
-       if (atomic_dec_and_test(&rcu_barrier_cpu_count))
-               complete(&rcu_barrier_completion);
-}
-
-/*
- * Called with preemption disabled, and from cross-cpu IRQ context.
- */
-static void rcu_barrier_func(void *type)
-{
-       int cpu = smp_processor_id();
-       struct rcu_head *head = &per_cpu(rcu_barrier_head, cpu);
-
-       atomic_inc(&rcu_barrier_cpu_count);
-       switch ((enum rcu_barrier)type) {
-       case RCU_BARRIER_STD:
-               call_rcu(head, rcu_barrier_callback);
-               break;
-       case RCU_BARRIER_BH:
-               call_rcu_bh(head, rcu_barrier_callback);
-               break;
-       case RCU_BARRIER_SCHED:
-               call_rcu_sched(head, rcu_barrier_callback);
-               break;
-       }
-}
-
-/*
- * Orchestrate the specified type of RCU barrier, waiting for all
- * RCU callbacks of the specified type to complete.
- */
-static void _rcu_barrier(enum rcu_barrier type)
-{
-       BUG_ON(in_interrupt());
-       /* Take cpucontrol mutex to protect against CPU hotplug */
-       mutex_lock(&rcu_barrier_mutex);
-       init_completion(&rcu_barrier_completion);
-       atomic_set(&rcu_barrier_cpu_count, 0);
-       /*
-        * The queueing of callbacks in all CPUs must be atomic with
-        * respect to RCU, otherwise one CPU may queue a callback,
-        * wait for a grace period, decrement barrier count and call
-        * complete(), while other CPUs have not yet queued anything.
-        * So, we need to make sure that grace periods cannot complete
-        * until all the callbacks are queued.
-        */
-       rcu_read_lock();
-       on_each_cpu(rcu_barrier_func, (void *)type, 1);
-       rcu_read_unlock();
-       wait_for_completion(&rcu_barrier_completion);
-       mutex_unlock(&rcu_barrier_mutex);
-}
-
-/**
- * rcu_barrier - Wait until all in-flight call_rcu() callbacks complete.
- */
-void rcu_barrier(void)
-{
-       _rcu_barrier(RCU_BARRIER_STD);
-}
-EXPORT_SYMBOL_GPL(rcu_barrier);
-
-/**
- * rcu_barrier_bh - Wait until all in-flight call_rcu_bh() callbacks complete.
- */
-void rcu_barrier_bh(void)
-{
-       _rcu_barrier(RCU_BARRIER_BH);
-}
-EXPORT_SYMBOL_GPL(rcu_barrier_bh);
-
-/**
- * rcu_barrier_sched - Wait for in-flight call_rcu_sched() callbacks.
- */
-void rcu_barrier_sched(void)
-{
-       _rcu_barrier(RCU_BARRIER_SCHED);
-}
-EXPORT_SYMBOL_GPL(rcu_barrier_sched);
-
-void __init rcu_init(void)
-{
-       __rcu_init();
-}
-