[deliverable/linux.git] / include / linux / preempt.h

#ifndef __LINUX_PREEMPT_H
#define __LINUX_PREEMPT_H

/*
 * include/linux/preempt.h - macros for accessing and manipulating
 * preempt_count (used for kernel preemption, interrupt count, etc.)
 */

#include <linux/linkage.h>
#include <linux/list.h>

/*
 * We put the hardirq and softirq counter into the preemption
 * counter. The bitmask has the following meaning:
 *
 * - bits 0-7 are the preemption count (max preemption depth: 256)
 * - bits 8-15 are the softirq count (max # of softirqs: 256)
 *
 * The hardirq count could in theory be the same as the number of
 * interrupts in the system, but we run all interrupt handlers with
 * interrupts disabled, so we cannot have nesting interrupts. Though
 * there are a few palaeontologic drivers which reenable interrupts in
 * the handler, so we need more than one bit here.
 *
 *         PREEMPT_MASK:	0x000000ff
 *         SOFTIRQ_MASK:	0x0000ff00
 *         HARDIRQ_MASK:	0x000f0000
 *             NMI_MASK:	0x00100000
 *       PREEMPT_ACTIVE:	0x00200000
 * PREEMPT_NEED_RESCHED:	0x80000000
 */
#define PREEMPT_BITS	8
#define SOFTIRQ_BITS	8
#define HARDIRQ_BITS	4
#define NMI_BITS	1

#define PREEMPT_SHIFT	0
#define SOFTIRQ_SHIFT	(PREEMPT_SHIFT + PREEMPT_BITS)
#define HARDIRQ_SHIFT	(SOFTIRQ_SHIFT + SOFTIRQ_BITS)
#define NMI_SHIFT	(HARDIRQ_SHIFT + HARDIRQ_BITS)

#define __IRQ_MASK(x)	((1UL << (x))-1)

#define PREEMPT_MASK	(__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT)
#define SOFTIRQ_MASK	(__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT)
#define HARDIRQ_MASK	(__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT)
#define NMI_MASK	(__IRQ_MASK(NMI_BITS)     << NMI_SHIFT)

#define PREEMPT_OFFSET	(1UL << PREEMPT_SHIFT)
#define SOFTIRQ_OFFSET	(1UL << SOFTIRQ_SHIFT)
#define HARDIRQ_OFFSET	(1UL << HARDIRQ_SHIFT)
#define NMI_OFFSET	(1UL << NMI_SHIFT)

#define SOFTIRQ_DISABLE_OFFSET	(2 * SOFTIRQ_OFFSET)

#define PREEMPT_ACTIVE_BITS	1
#define PREEMPT_ACTIVE_SHIFT	(NMI_SHIFT + NMI_BITS)
#define PREEMPT_ACTIVE	(__IRQ_MASK(PREEMPT_ACTIVE_BITS) << PREEMPT_ACTIVE_SHIFT)

/* We use the MSB mostly because its available */
#define PREEMPT_NEED_RESCHED	0x80000000

/* preempt_count() and related functions, depends on PREEMPT_NEED_RESCHED */
#include <asm/preempt.h>

#define hardirq_count()	(preempt_count() & HARDIRQ_MASK)
#define softirq_count()	(preempt_count() & SOFTIRQ_MASK)
#define irq_count()	(preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK \
				 | NMI_MASK))

/*
 * Are we doing bottom half or hardware interrupt processing?
 * Are we in a softirq context? Interrupt context?
 * in_softirq - Are we currently processing softirq or have bh disabled?
 * in_serving_softirq - Are we currently processing softirq?
 */
#define in_irq()		(hardirq_count())
#define in_softirq()		(softirq_count())
#define in_interrupt()		(irq_count())
#define in_serving_softirq()	(softirq_count() & SOFTIRQ_OFFSET)

/*
 * Are we in NMI context?
 */
#define in_nmi()	(preempt_count() & NMI_MASK)

/*
 * The preempt_count offset after preempt_disable();
 */
#if defined(CONFIG_PREEMPT_COUNT)
# define PREEMPT_DISABLE_OFFSET	PREEMPT_OFFSET
#else
# define PREEMPT_DISABLE_OFFSET	0
#endif

/*
 * The preempt_count offset after spin_lock()
 */
#define PREEMPT_LOCK_OFFSET	PREEMPT_DISABLE_OFFSET

/*
 * The preempt_count offset needed for things like:
 *
 *  spin_lock_bh()
 *
 * Which need to disable both preemption (CONFIG_PREEMPT_COUNT) and
 * softirqs, such that unlock sequences of:
 *
 *  spin_unlock();
 *  local_bh_enable();
 *
 * Work as expected.
 */
#define SOFTIRQ_LOCK_OFFSET (SOFTIRQ_DISABLE_OFFSET + PREEMPT_LOCK_OFFSET)

/*
 * Are we running in atomic context?  WARNING: this macro cannot
 * always detect atomic context; in particular, it cannot know about
 * held spinlocks in non-preemptible kernels.  Thus it should not be
 * used in the general case to determine whether sleeping is possible.
 * Do not use in_atomic() in driver code.
 */
#define in_atomic()	(preempt_count() != 0)

/*
 * Check whether we were atomic before we did preempt_disable():
 * (used by the scheduler)
 */
#define in_atomic_preempt_off() \
		((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_DISABLE_OFFSET)

#if defined(CONFIG_DEBUG_PREEMPT) || defined(CONFIG_PREEMPT_TRACER)
extern void preempt_count_add(int val);
extern void preempt_count_sub(int val);
#define preempt_count_dec_and_test() \
	({ preempt_count_sub(1); should_resched(0); })
#else
#define preempt_count_add(val)	__preempt_count_add(val)
#define preempt_count_sub(val)	__preempt_count_sub(val)
#define preempt_count_dec_and_test() __preempt_count_dec_and_test()
#endif

#define __preempt_count_inc() __preempt_count_add(1)
#define __preempt_count_dec() __preempt_count_sub(1)

#define preempt_count_inc() preempt_count_add(1)
#define preempt_count_dec() preempt_count_sub(1)

#define preempt_active_enter() \
do { \
	preempt_count_add(PREEMPT_ACTIVE + PREEMPT_DISABLE_OFFSET); \
	barrier(); \
} while (0)

#define preempt_active_exit() \
do { \
	barrier(); \
	preempt_count_sub(PREEMPT_ACTIVE + PREEMPT_DISABLE_OFFSET); \
} while (0)

#ifdef CONFIG_PREEMPT_COUNT

#define preempt_disable() \
do { \
	preempt_count_inc(); \
	barrier(); \
} while (0)

#define sched_preempt_enable_no_resched() \
do { \
	barrier(); \
	preempt_count_dec(); \
} while (0)

#define preempt_enable_no_resched() sched_preempt_enable_no_resched()

#define preemptible()	(preempt_count() == 0 && !irqs_disabled())

#ifdef CONFIG_PREEMPT
#define preempt_enable() \
do { \
	barrier(); \
	if (unlikely(preempt_count_dec_and_test())) \
		__preempt_schedule(); \
} while (0)

#define preempt_enable_notrace() \
do { \
	barrier(); \
	if (unlikely(__preempt_count_dec_and_test())) \
		__preempt_schedule_notrace(); \
} while (0)

#define preempt_check_resched() \
do { \
	if (should_resched(0)) \
		__preempt_schedule(); \
} while (0)

#else /* !CONFIG_PREEMPT */
#define preempt_enable() \
do { \
	barrier(); \
	preempt_count_dec(); \
} while (0)

#define preempt_enable_notrace() \
do { \
	barrier(); \
	__preempt_count_dec(); \
} while (0)

#define preempt_check_resched() do { } while (0)
#endif /* CONFIG_PREEMPT */

#define preempt_disable_notrace() \
do { \
	__preempt_count_inc(); \
	barrier(); \
} while (0)

#define preempt_enable_no_resched_notrace() \
do { \
	barrier(); \
	__preempt_count_dec(); \
} while (0)

#else /* !CONFIG_PREEMPT_COUNT */

/*
 * Even if we don't have any preemption, we need preempt disable/enable
 * to be barriers, so that we don't have things like get_user/put_user
 * that can cause faults and scheduling migrate into our preempt-protected
 * region.
 */
#define preempt_disable()			barrier()
#define sched_preempt_enable_no_resched()	barrier()
#define preempt_enable_no_resched()		barrier()
#define preempt_enable()			barrier()
#define preempt_check_resched()			do { } while (0)

#define preempt_disable_notrace()		barrier()
#define preempt_enable_no_resched_notrace()	barrier()
#define preempt_enable_notrace()		barrier()
#define preemptible()				0

#endif /* CONFIG_PREEMPT_COUNT */

#ifdef MODULE
/*
 * Modules have no business playing preemption tricks.
 */
#undef sched_preempt_enable_no_resched
#undef preempt_enable_no_resched
#undef preempt_enable_no_resched_notrace
#undef preempt_check_resched
#endif

#define preempt_set_need_resched() \
do { \
	set_preempt_need_resched(); \
} while (0)
#define preempt_fold_need_resched() \
do { \
	if (tif_need_resched()) \
		set_preempt_need_resched(); \
} while (0)

#ifdef CONFIG_PREEMPT_NOTIFIERS

struct preempt_notifier;

/**
 * preempt_ops - notifiers called when a task is preempted and rescheduled
 * @sched_in: we're about to be rescheduled:
 *    notifier: struct preempt_notifier for the task being scheduled
 *    cpu:  cpu we're scheduled on
 * @sched_out: we've just been preempted
 *    notifier: struct preempt_notifier for the task being preempted
 *    next: the task that's kicking us out
 *
 * Please note that sched_in and out are called under different
 * contexts.  sched_out is called with rq lock held and irq disabled
 * while sched_in is called without rq lock and irq enabled.  This
 * difference is intentional and depended upon by its users.
 */
struct preempt_ops {
	void (*sched_in)(struct preempt_notifier *notifier, int cpu);
	void (*sched_out)(struct preempt_notifier *notifier,
			  struct task_struct *next);
};

/**
 * preempt_notifier - key for installing preemption notifiers
 * @link: internal use
 * @ops: defines the notifier functions to be called
 *
 * Usually used in conjunction with container_of().
 */
struct preempt_notifier {
	struct hlist_node link;
	struct preempt_ops *ops;
};

void preempt_notifier_inc(void);
void preempt_notifier_dec(void);
void preempt_notifier_register(struct preempt_notifier *notifier);
void preempt_notifier_unregister(struct preempt_notifier *notifier);

static inline void preempt_notifier_init(struct preempt_notifier *notifier,
				     struct preempt_ops *ops)
{
	INIT_HLIST_NODE(&notifier->link);
	notifier->ops = ops;
}

#endif

#endif /* __LINUX_PREEMPT_H */
Commit	Line	Data
1da177e4 LT	1	#ifndef __LINUX_PREEMPT_H
	2	#define __LINUX_PREEMPT_H
	3
	4	/*
	5	* include/linux/preempt.h - macros for accessing and manipulating
	6	* preempt_count (used for kernel preemption, interrupt count, etc.)
	7	*/
	8
1da177e4	9	#include <linux/linkage.h>
e107be36	10	#include <linux/list.h>
1da177e4	11
92cf2118 FW	12	/*
	13	* We put the hardirq and softirq counter into the preemption
	14	* counter. The bitmask has the following meaning:
	15	*
	16	* - bits 0-7 are the preemption count (max preemption depth: 256)
	17	* - bits 8-15 are the softirq count (max # of softirqs: 256)
	18	*
	19	* The hardirq count could in theory be the same as the number of
	20	* interrupts in the system, but we run all interrupt handlers with
	21	* interrupts disabled, so we cannot have nesting interrupts. Though
	22	* there are a few palaeontologic drivers which reenable interrupts in
	23	* the handler, so we need more than one bit here.
	24	*
2e10e71c FW	25	* PREEMPT_MASK: 0x000000ff
	26	* SOFTIRQ_MASK: 0x0000ff00
	27	* HARDIRQ_MASK: 0x000f0000
	28	* NMI_MASK: 0x00100000
	29	* PREEMPT_ACTIVE: 0x00200000
	30	* PREEMPT_NEED_RESCHED: 0x80000000
92cf2118 FW	31	*/
	32	#define PREEMPT_BITS 8
	33	#define SOFTIRQ_BITS 8
	34	#define HARDIRQ_BITS 4
	35	#define NMI_BITS 1
	36
	37	#define PREEMPT_SHIFT 0
	38	#define SOFTIRQ_SHIFT (PREEMPT_SHIFT + PREEMPT_BITS)
	39	#define HARDIRQ_SHIFT (SOFTIRQ_SHIFT + SOFTIRQ_BITS)
	40	#define NMI_SHIFT (HARDIRQ_SHIFT + HARDIRQ_BITS)
	41
	42	#define __IRQ_MASK(x) ((1UL << (x))-1)
	43
	44	#define PREEMPT_MASK (__IRQ_MASK(PREEMPT_BITS) << PREEMPT_SHIFT)
	45	#define SOFTIRQ_MASK (__IRQ_MASK(SOFTIRQ_BITS) << SOFTIRQ_SHIFT)
	46	#define HARDIRQ_MASK (__IRQ_MASK(HARDIRQ_BITS) << HARDIRQ_SHIFT)
	47	#define NMI_MASK (__IRQ_MASK(NMI_BITS) << NMI_SHIFT)
	48
	49	#define PREEMPT_OFFSET (1UL << PREEMPT_SHIFT)
	50	#define SOFTIRQ_OFFSET (1UL << SOFTIRQ_SHIFT)
	51	#define HARDIRQ_OFFSET (1UL << HARDIRQ_SHIFT)
	52	#define NMI_OFFSET (1UL << NMI_SHIFT)
	53
	54	#define SOFTIRQ_DISABLE_OFFSET (2 * SOFTIRQ_OFFSET)
	55
	56	#define PREEMPT_ACTIVE_BITS 1
	57	#define PREEMPT_ACTIVE_SHIFT (NMI_SHIFT + NMI_BITS)
	58	#define PREEMPT_ACTIVE (__IRQ_MASK(PREEMPT_ACTIVE_BITS) << PREEMPT_ACTIVE_SHIFT)
	59
2e10e71c FW	60	/* We use the MSB mostly because its available */
	61	#define PREEMPT_NEED_RESCHED 0x80000000
	62
	63	/* preempt_count() and related functions, depends on PREEMPT_NEED_RESCHED */
	64	#include <asm/preempt.h>
	65
92cf2118 FW	66	#define hardirq_count() (preempt_count() & HARDIRQ_MASK)
	67	#define softirq_count() (preempt_count() & SOFTIRQ_MASK)
	68	#define irq_count() (preempt_count() & (HARDIRQ_MASK \| SOFTIRQ_MASK \
	69	\| NMI_MASK))
	70
	71	/*
	72	* Are we doing bottom half or hardware interrupt processing?
	73	* Are we in a softirq context? Interrupt context?
	74	* in_softirq - Are we currently processing softirq or have bh disabled?
	75	* in_serving_softirq - Are we currently processing softirq?
	76	*/
	77	#define in_irq() (hardirq_count())
	78	#define in_softirq() (softirq_count())
	79	#define in_interrupt() (irq_count())
	80	#define in_serving_softirq() (softirq_count() & SOFTIRQ_OFFSET)
	81
	82	/*
	83	* Are we in NMI context?
	84	*/
	85	#define in_nmi() (preempt_count() & NMI_MASK)
	86
fe32d3cd KK	87	/*
	88	* The preempt_count offset after preempt_disable();
	89	*/
92cf2118	90	#if defined(CONFIG_PREEMPT_COUNT)
fe32d3cd	91	# define PREEMPT_DISABLE_OFFSET PREEMPT_OFFSET
92cf2118	92	#else
fe32d3cd	93	# define PREEMPT_DISABLE_OFFSET 0
92cf2118 FW	94	#endif
92cf2118 FW	95
fe32d3cd KK	96	/*
	97	* The preempt_count offset after spin_lock()
	98	*/
	99	#define PREEMPT_LOCK_OFFSET PREEMPT_DISABLE_OFFSET
	100
92cf2118 FW	101	/*
	102	* The preempt_count offset needed for things like:
	103	*
	104	* spin_lock_bh()
	105	*
	106	* Which need to disable both preemption (CONFIG_PREEMPT_COUNT) and
	107	* softirqs, such that unlock sequences of:
	108	*
	109	* spin_unlock();
	110	* local_bh_enable();
	111	*
	112	* Work as expected.
	113	*/
fe32d3cd	114	#define SOFTIRQ_LOCK_OFFSET (SOFTIRQ_DISABLE_OFFSET + PREEMPT_LOCK_OFFSET)
92cf2118 FW	115
	116	/*
	117	* Are we running in atomic context? WARNING: this macro cannot
	118	* always detect atomic context; in particular, it cannot know about
	119	* held spinlocks in non-preemptible kernels. Thus it should not be
	120	* used in the general case to determine whether sleeping is possible.
	121	* Do not use in_atomic() in driver code.
	122	*/
3e51f3c4	123	#define in_atomic() (preempt_count() != 0)
92cf2118 FW	124
	125	/*
	126	* Check whether we were atomic before we did preempt_disable():
e017cf21	127	* (used by the scheduler)
92cf2118 FW	128	*/
92cf2118 FW	129	#define in_atomic_preempt_off() \
90b62b51	130	((preempt_count() & ~PREEMPT_ACTIVE) != PREEMPT_DISABLE_OFFSET)
92cf2118	131
6cd8a4bb	132	#if defined(CONFIG_DEBUG_PREEMPT) \|\| defined(CONFIG_PREEMPT_TRACER)
bdb43806 PZ	133	extern void preempt_count_add(int val);
bdb43806 PZ	134	extern void preempt_count_sub(int val);
fe32d3cd KK	135	#define preempt_count_dec_and_test() \
fe32d3cd KK	136	({ preempt_count_sub(1); should_resched(0); })
1da177e4	137	#else
bdb43806 PZ	138	#define preempt_count_add(val) __preempt_count_add(val)
	139	#define preempt_count_sub(val) __preempt_count_sub(val)
	140	#define preempt_count_dec_and_test() __preempt_count_dec_and_test()
1da177e4 LT	141	#endif
1da177e4 LT	142
bdb43806 PZ	143	#define __preempt_count_inc() __preempt_count_add(1)
bdb43806 PZ	144	#define __preempt_count_dec() __preempt_count_sub(1)
bdd4e85d	145
bdb43806 PZ	146	#define preempt_count_inc() preempt_count_add(1)
bdb43806 PZ	147	#define preempt_count_dec() preempt_count_sub(1)
bdd4e85d	148
b30f0e3f FW	149	#define preempt_active_enter() \
	150	do { \
	151	preempt_count_add(PREEMPT_ACTIVE + PREEMPT_DISABLE_OFFSET); \
	152	barrier(); \
	153	} while (0)
	154
	155	#define preempt_active_exit() \
	156	do { \
	157	barrier(); \
	158	preempt_count_sub(PREEMPT_ACTIVE + PREEMPT_DISABLE_OFFSET); \
	159	} while (0)
	160
bdd4e85d FW	161	#ifdef CONFIG_PREEMPT_COUNT
bdd4e85d FW	162
1da177e4 LT	163	#define preempt_disable() \
1da177e4 LT	164	do { \
bdb43806	165	preempt_count_inc(); \
1da177e4 LT	166	barrier(); \
	167	} while (0)
	168
ba74c144	169	#define sched_preempt_enable_no_resched() \
1da177e4 LT	170	do { \
1da177e4 LT	171	barrier(); \
bdb43806	172	preempt_count_dec(); \
1da177e4 LT	173	} while (0)
1da177e4 LT	174
bdb43806	175	#define preempt_enable_no_resched() sched_preempt_enable_no_resched()
ba74c144	176
2e10e71c FW	177	#define preemptible() (preempt_count() == 0 && !irqs_disabled())
2e10e71c FW	178
bdb43806	179	#ifdef CONFIG_PREEMPT
1da177e4 LT	180	#define preempt_enable() \
1da177e4 LT	181	do { \
bdb43806 PZ	182	barrier(); \
bdb43806 PZ	183	if (unlikely(preempt_count_dec_and_test())) \
1a338ac3	184	__preempt_schedule(); \
1da177e4 LT	185	} while (0)
1da177e4 LT	186
9a92e3dc FW	187	#define preempt_enable_notrace() \
	188	do { \
	189	barrier(); \
	190	if (unlikely(__preempt_count_dec_and_test())) \
	191	__preempt_schedule_notrace(); \
	192	} while (0)
	193
bdb43806 PZ	194	#define preempt_check_resched() \
bdb43806 PZ	195	do { \
fe32d3cd	196	if (should_resched(0)) \
1a338ac3	197	__preempt_schedule(); \
bdb43806 PZ	198	} while (0)
bdb43806 PZ	199
9a92e3dc	200	#else /* !CONFIG_PREEMPT */
62b94a08 PZ	201	#define preempt_enable() \
	202	do { \
	203	barrier(); \
	204	preempt_count_dec(); \
	205	} while (0)
50282528	206
9a92e3dc	207	#define preempt_enable_notrace() \
50282528 SR	208	do { \
50282528 SR	209	barrier(); \
bdb43806	210	__preempt_count_dec(); \
50282528 SR	211	} while (0)
50282528 SR	212
9a92e3dc FW	213	#define preempt_check_resched() do { } while (0)
9a92e3dc FW	214	#endif /* CONFIG_PREEMPT */
bdb43806	215
9a92e3dc	216	#define preempt_disable_notrace() \
50282528	217	do { \
9a92e3dc	218	__preempt_count_inc(); \
bdb43806	219	barrier(); \
50282528	220	} while (0)
9a92e3dc FW	221
9a92e3dc FW	222	#define preempt_enable_no_resched_notrace() \
62b94a08 PZ	223	do { \
	224	barrier(); \
	225	__preempt_count_dec(); \
	226	} while (0)
50282528	227
bdd4e85d	228	#else /* !CONFIG_PREEMPT_COUNT */
1da177e4	229
386afc91 LT	230	/*
	231	* Even if we don't have any preemption, we need preempt disable/enable
	232	* to be barriers, so that we don't have things like get_user/put_user
	233	* that can cause faults and scheduling migrate into our preempt-protected
	234	* region.
	235	*/
bdb43806	236	#define preempt_disable() barrier()
386afc91	237	#define sched_preempt_enable_no_resched() barrier()
bdb43806 PZ	238	#define preempt_enable_no_resched() barrier()
	239	#define preempt_enable() barrier()
	240	#define preempt_check_resched() do { } while (0)
386afc91 LT	241
	242	#define preempt_disable_notrace() barrier()
	243	#define preempt_enable_no_resched_notrace() barrier()
	244	#define preempt_enable_notrace() barrier()
2e10e71c	245	#define preemptible() 0
50282528	246
bdd4e85d	247	#endif /* CONFIG_PREEMPT_COUNT */
1da177e4	248
62b94a08 PZ	249	#ifdef MODULE
	250	/*
	251	* Modules have no business playing preemption tricks.
	252	*/
	253	#undef sched_preempt_enable_no_resched
	254	#undef preempt_enable_no_resched
	255	#undef preempt_enable_no_resched_notrace
	256	#undef preempt_check_resched
	257	#endif
	258
8cb75e0c PZ	259	#define preempt_set_need_resched() \
	260	do { \
	261	set_preempt_need_resched(); \
	262	} while (0)
	263	#define preempt_fold_need_resched() \
	264	do { \
	265	if (tif_need_resched()) \
	266	set_preempt_need_resched(); \
	267	} while (0)
8cb75e0c	268
e107be36 AK	269	#ifdef CONFIG_PREEMPT_NOTIFIERS
	270
	271	struct preempt_notifier;
	272
	273	/**
	274	* preempt_ops - notifiers called when a task is preempted and rescheduled
	275	* @sched_in: we're about to be rescheduled:
	276	* notifier: struct preempt_notifier for the task being scheduled
	277	* cpu: cpu we're scheduled on
	278	* @sched_out: we've just been preempted
	279	* notifier: struct preempt_notifier for the task being preempted
	280	* next: the task that's kicking us out
8592e648 TH	281	*
	282	* Please note that sched_in and out are called under different
	283	* contexts. sched_out is called with rq lock held and irq disabled
	284	* while sched_in is called without rq lock and irq enabled. This
	285	* difference is intentional and depended upon by its users.
e107be36 AK	286	*/
	287	struct preempt_ops {
	288	void (sched_in)(struct preempt_notifier notifier, int cpu);
	289	void (sched_out)(struct preempt_notifier notifier,
	290	struct task_struct *next);
	291	};
	292
	293	/**
	294	* preempt_notifier - key for installing preemption notifiers
	295	* @link: internal use
	296	* @ops: defines the notifier functions to be called
	297	*
	298	* Usually used in conjunction with container_of().
	299	*/
	300	struct preempt_notifier {
	301	struct hlist_node link;
	302	struct preempt_ops *ops;
	303	};
	304
2ecd9d29 PZ	305	void preempt_notifier_inc(void);
2ecd9d29 PZ	306	void preempt_notifier_dec(void);
e107be36 AK	307	void preempt_notifier_register(struct preempt_notifier *notifier);
	308	void preempt_notifier_unregister(struct preempt_notifier *notifier);
	309
	310	static inline void preempt_notifier_init(struct preempt_notifier *notifier,
	311	struct preempt_ops *ops)
	312	{
	313	INIT_HLIST_NODE(&notifier->link);
	314	notifier->ops = ops;
	315	}
	316
	317	#endif
	318
1da177e4	319	#endif /* __LINUX_PREEMPT_H */