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Commit b8c7f1dc authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'core-fixes-for-linus' of... 

Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  rcu: Fix whitespace inconsistencies
  rcu: Fix thinko, actually initialize full tree
  rcu: Apply results of code inspection of kernel/rcutree_plugin.h
  rcu: Add WARN_ON_ONCE() consistency checks covering state transitions
  rcu: Fix synchronize_rcu() for TREE_PREEMPT_RCU
  rcu: Simplify rcu_read_unlock_special() quiescent-state accounting
  rcu: Add debug checks to TREE_PREEMPT_RCU for premature grace periods
  rcu: Kconfig help needs to say that TREE_PREEMPT_RCU scales down
  rcutorture: Occasionally delay readers enough to make RCU force_quiescent_state
  rcu: Initialize multi-level RCU grace periods holding locks
  rcu: Need to update rnp->gpnum if preemptable RCU is to be reliable
parents f4eccb6d a71fca58

include/linux/rcupdate.h

+8 −21
Original line number Diff line number Diff line
@@ -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.

include/linux/rcutree.h

+3 −3
Original line number Diff line number Diff line
@@ -53,6 +53,8 @@ static inline void __rcu_read_unlock(void) 
	preempt_enable();

}



#define __synchronize_sched() synchronize_rcu()



static inline void exit_rcu(void)

{

}
@@ -68,8 +70,6 @@ static inline void __rcu_read_unlock_bh(void) 
	local_bh_enable();

}



#define __synchronize_sched() synchronize_rcu()



extern void call_rcu_sched(struct rcu_head *head,

			   void (*func)(struct rcu_head *rcu));

include/linux/sched.h

+0 −1
Original line number Diff line number Diff line
@@ -1755,7 +1755,6 @@ extern cputime_t task_gtime(struct task_struct *p); 


#define RCU_READ_UNLOCK_BLOCKED (1 << 0) /* blocked while in RCU read-side. */

#define RCU_READ_UNLOCK_NEED_QS (1 << 1) /* RCU core needs CPU response. */

#define RCU_READ_UNLOCK_GOT_QS  (1 << 2) /* CPU has responded to RCU core. */



static inline void rcu_copy_process(struct task_struct *p)

{

init/Kconfig

+2 −1
Original line number Diff line number Diff line
@@ -331,7 +331,8 @@ config TREE_PREEMPT_RCU 
	  This option selects the RCU implementation that is

	  designed for very large SMP systems with hundreds or

	  thousands of CPUs, but for which real-time response

	  is also required.

	  is also required.  It also scales down nicely to

	  smaller systems.



endchoice

kernel/rcupdate.c

+45 −3
Original line number Diff line number Diff line
@@ -74,6 +74,8 @@ void wakeme_after_rcu(struct rcu_head *head) 
	complete(&rcu->completion);

}



#ifdef CONFIG_TREE_PREEMPT_RCU



/**

 * synchronize_rcu - wait until a grace period has elapsed.

 *
@@ -87,7 +89,7 @@ void synchronize_rcu(void) 
{

	struct rcu_synchronize rcu;



	if (rcu_blocking_is_gp())

	if (!rcu_scheduler_active)

		return;



	init_completion(&rcu.completion);
@@ -98,6 +100,46 @@ void synchronize_rcu(void) 
}

EXPORT_SYMBOL_GPL(synchronize_rcu);



#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */



/**

 * synchronize_sched - wait until an rcu-sched grace period has elapsed.

 *

 * Control will return to the caller some time after a full rcu-sched

 * grace period has elapsed, in other words after all currently executing

 * rcu-sched read-side critical sections have completed.   These read-side

 * critical sections are delimited by rcu_read_lock_sched() and

 * rcu_read_unlock_sched(), and may be nested.  Note that preempt_disable(),

 * local_irq_disable(), and so on may be used in place of

 * rcu_read_lock_sched().

 *

 * 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.

 */

void synchronize_sched(void)

{

	struct rcu_synchronize rcu;



	if (rcu_blocking_is_gp())

		return;



	init_completion(&rcu.completion);

	/* Will wake me after RCU finished. */

	call_rcu_sched(&rcu.head, wakeme_after_rcu);

	/* Wait for it. */

	wait_for_completion(&rcu.completion);

}

EXPORT_SYMBOL_GPL(synchronize_sched);



/**

 * synchronize_rcu_bh - wait until an rcu_bh grace period has elapsed.

 *