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rcu: Fix synchronize_rcu() for TREE_PREEMPT_RCU

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The redirection of synchronize_sched() to synchronize_rcu() was
appropriate for TREE_RCU, but not for TREE_PREEMPT_RCU.

Fix this by creating an underlying synchronize_sched().  TREE_RCU
then redirects synchronize_rcu() to synchronize_sched(), while
TREE_PREEMPT_RCU has its own version of synchronize_rcu().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: akpm@linux-foundation.org
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
LKML-Reference: <12528585111916-git-send-email->
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Paul E. McKenney
2009-09-13 09:15:11 -07:00
committed by Ingo Molnar
parent c3422bea5f
commit 16e3081191
3 changed files with 50 additions and 21 deletions
Download Patch File Download Diff File Expand all files Collapse all files
include/linux/rcupdate.h
+5 -18
View File
@@ -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);
@@ -261,24 +266,6 @@ 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.