include/linux/sched.h

#ifndef _LINUX_SCHED_H
#define _LINUX_SCHED_H

#include <asm/param.h>	/* for HZ */

extern unsigned long event;

#include <linux/config.h>
#include <linux/binfmts.h>
#include <linux/threads.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/times.h>
#include <linux/timex.h>
#include <linux/rbtree.h>

#include <asm/system.h>
#include <asm/semaphore.h>
#include <asm/page.h>
#include <asm/ptrace.h>
#include <asm/mmu.h>

#include <linux/smp.h>
#include <linux/sem.h>
#include <linux/signal.h>
#include <linux/securebits.h>
#include <linux/fs_struct.h>
#include <linux/compiler.h>

struct exec_domain;

/*
 * cloning flags:
 */
#define CSIGNAL		0x000000ff	/* signal mask to be sent at exit */
#define CLONE_VM	0x00000100	/* set if VM shared between processes */
#define CLONE_FS	0x00000200	/* set if fs info shared between processes */
#define CLONE_FILES	0x00000400	/* set if open files shared between processes */
#define CLONE_SIGHAND	0x00000800	/* set if signal handlers and blocked signals shared */
#define CLONE_PID	0x00001000	/* set if pid shared */
#define CLONE_PTRACE	0x00002000	/* set if we want to let tracing continue on the child too */
#define CLONE_VFORK	0x00004000	/* set if the parent wants the child to wake it up on mm_release */
#define CLONE_PARENT	0x00008000	/* set if we want to have the same parent as the cloner */
#define CLONE_THREAD	0x00010000	/* Same thread group? */
#define CLONE_NEWNS	0x00020000	/* New namespace group? */

#define CLONE_SIGNAL	(CLONE_SIGHAND | CLONE_THREAD)

/*
 * These are the constant used to fake the fixed-point load-average
 * counting. Some notes:
 *  - 11 bit fractions expand to 22 bits by the multiplies: this gives
 *    a load-average precision of 10 bits integer + 11 bits fractional
 *  - if you want to count load-averages more often, you need more
 *    precision, or rounding will get you. With 2-second counting freq,
 *    the EXP_n values would be 1981, 2034 and 2043 if still using only
 *    11 bit fractions.
 */
extern unsigned long avenrun[];		/* Load averages */

#define FSHIFT		11		/* nr of bits of precision */
#define FIXED_1		(1<<FSHIFT)	/* 1.0 as fixed-point */
#define LOAD_FREQ	(5*HZ)		/* 5 sec intervals */
#define EXP_1		1884		/* 1/exp(5sec/1min) as fixed-point */
#define EXP_5		2014		/* 1/exp(5sec/5min) */
#define EXP_15		2037		/* 1/exp(5sec/15min) */

#define CALC_LOAD(load,exp,n) \
	load *= exp; \
	load += n*(FIXED_1-exp); \
	load >>= FSHIFT;

#define CT_TO_SECS(x)	((x) / HZ)
#define CT_TO_USECS(x)	(((x) % HZ) * 1000000/HZ)

extern int nr_threads;
extern int last_pid;
extern unsigned long nr_running(void);

#include <linux/fs.h>
#include <linux/time.h>
#include <linux/param.h>
#include <linux/resource.h>
#include <linux/timer.h>

#include <asm/processor.h>

#define TASK_RUNNING		0
#define TASK_INTERRUPTIBLE	1
#define TASK_UNINTERRUPTIBLE	2
#define TASK_ZOMBIE		4
#define TASK_STOPPED		8

#define __set_task_state(tsk, state_value)		\
	do { (tsk)->state = (state_value); } while (0)
#ifdef CONFIG_SMP
#define set_task_state(tsk, state_value)		\
	set_mb((tsk)->state, (state_value))
#else
#define set_task_state(tsk, state_value)		\
	__set_task_state((tsk), (state_value))
#endif

#define __set_current_state(state_value)			\
	do { current->state = (state_value); } while (0)
#ifdef CONFIG_SMP
#define set_current_state(state_value)		\
	set_mb(current->state, (state_value))
#else
#define set_current_state(state_value)		\
	__set_current_state(state_value)
#endif

/*
 * Scheduling policies
 */
#define SCHED_OTHER		0
#define SCHED_FIFO		1
#define SCHED_RR		2

struct sched_param {
	int sched_priority;
};

struct completion;

#ifdef __KERNEL__

#include <linux/spinlock.h>

/*
 * This serializes "schedule()" and also protects
 * the run-queue from deletions/modifications (but
 * _adding_ to the beginning of the run-queue has
 * a separate lock).
 */
extern rwlock_t tasklist_lock;
extern spinlock_t mmlist_lock;

typedef struct task_struct task_t;

extern void sched_init(void);
extern void init_idle(task_t *idle, int cpu);
extern void show_state(void);
extern void cpu_init (void);
extern void trap_init(void);
extern void update_process_times(int user);
extern void update_one_process(struct task_struct *p, unsigned long user,
			       unsigned long system, int cpu);
extern void scheduler_tick(struct task_struct *p);
extern void sched_task_migrated(struct task_struct *p);
extern void smp_migrate_task(int cpu, task_t *task);
extern unsigned long cache_decay_ticks;


#define	MAX_SCHEDULE_TIMEOUT	LONG_MAX
extern signed long FASTCALL(schedule_timeout(signed long timeout));
asmlinkage void schedule(void);

extern int schedule_task(struct tq_struct *task);
extern void flush_scheduled_tasks(void);
extern int start_context_thread(void);
extern int current_is_keventd(void);

struct namespace;

/* Maximum number of active map areas.. This is a random (large) number */
#define MAX_MAP_COUNT	(65536)

struct mm_struct {
	struct vm_area_struct * mmap;		/* list of VMAs */
	rb_root_t mm_rb;
	struct vm_area_struct * mmap_cache;	/* last find_vma result */
	pgd_t * pgd;
	atomic_t mm_users;			/* How many users with user space? */
	atomic_t mm_count;			/* How many references to "struct mm_struct" (users count as 1) */
	int map_count;				/* number of VMAs */
	struct rw_semaphore mmap_sem;
	spinlock_t page_table_lock;		/* Protects task page tables and mm->rss */

	struct list_head mmlist;		/* List of all active mm's.  These are globally strung
						 * together off init_mm.mmlist, and are protected
						 * by mmlist_lock
						 */

	unsigned long start_code, end_code, start_data, end_data;
	unsigned long start_brk, brk, start_stack;
	unsigned long arg_start, arg_end, env_start, env_end;
	unsigned long rss, total_vm, locked_vm;
	unsigned long def_flags;
	unsigned long cpu_vm_mask;
	unsigned long swap_address;

	unsigned dumpable:1;

	/* Architecture-specific MM context */
	mm_context_t context;
};

extern int mmlist_nr;

struct signal_struct {
	atomic_t		count;
	struct k_sigaction	action[_NSIG];
	spinlock_t		siglock;
};


/*
 * Some day this will be a full-fledged user tracking system..
 */
struct user_struct {
	atomic_t __count;	/* reference count */
	atomic_t processes;	/* How many processes does this user have? */
	atomic_t files;		/* How many open files does this user have? */

	/* Hash table maintenance information */
	struct user_struct *next, **pprev;
	uid_t uid;
};

#define get_current_user() ({ 				\
	struct user_struct *__user = current->user;	\
	atomic_inc(&__user->__count);			\
	__user; })

extern struct user_struct root_user;
#define INIT_USER (&root_user)

typedef struct prio_array prio_array_t;

/* this struct must occupy one 32-bit chunk so that is can be read in one go */
struct task_work {
	__s8	need_resched;
	__u8	syscall_trace;	/* count of syscall interceptors */
	__u8	sigpending;
	__u8	notify_resume;	/* request for notification on
				   userspace execution resumption */
} __attribute__((packed));

struct task_struct {
	/*
	 * offsets of these are hardcoded elsewhere - touch with care
	 */
	volatile long state;	/* -1 unrunnable, 0 runnable, >0 stopped */
	unsigned long flags;	/* per process flags, defined below */
	volatile struct task_work work;

	mm_segment_t addr_limit;	/* thread address space:
					 	0-0xBFFFFFFF for user-thead
						0-0xFFFFFFFF for kernel-thread
					 */
	struct exec_domain *exec_domain;
	long __pad;
	unsigned long ptrace;

	int lock_depth;		/* Lock depth */

	/*
	 * offset 32 begins here on 32-bit platforms.
	 */
	unsigned int cpu;
	int prio;
	long __nice;
	list_t run_list;
	prio_array_t *array;

	unsigned int time_slice;

	unsigned long sleep_avg;
	unsigned long sleep_timestamp;

	unsigned long policy;
	unsigned long cpus_allowed;

	struct task_struct *next_task, *prev_task;

	struct mm_struct *mm, *active_mm;
	struct list_head local_pages;

	unsigned int allocation_order, nr_local_pages;

/* task state */
	struct linux_binfmt *binfmt;
	int exit_code, exit_signal;
	int pdeath_signal;  /*  The signal sent when the parent dies  */
	/* ??? */
	unsigned long personality;
	int did_exec:1;
	pid_t pid;
	pid_t pgrp;
	pid_t tty_old_pgrp;
	pid_t session;
	pid_t tgid;
	/* boolean value for session group leader */
	int leader;
	/* 
	 * pointers to (original) parent process, youngest child, younger sibling,
	 * older sibling, respectively.  (p->father can be replaced with 
	 * p->p_pptr->pid)
	 */
	struct task_struct *p_opptr, *p_pptr, *p_cptr, *p_ysptr, *p_osptr;
	struct list_head thread_group;

	/* PID hash table linkage. */
	struct task_struct *pidhash_next;
	struct task_struct **pidhash_pprev;

	wait_queue_head_t wait_chldexit;	/* for wait4() */
	struct completion *vfork_done;		/* for vfork() */
	unsigned long rt_priority;
	unsigned long it_real_value, it_prof_value, it_virt_value;
	unsigned long it_real_incr, it_prof_incr, it_virt_incr;
	struct timer_list real_timer;
	struct tms times;
	unsigned long start_time;
	long per_cpu_utime[NR_CPUS], per_cpu_stime[NR_CPUS];
/* mm fault and swap info: this can arguably be seen as either mm-specific or thread-specific */
	unsigned long min_flt, maj_flt, nswap, cmin_flt, cmaj_flt, cnswap;
	int swappable:1;
/* process credentials */
	uid_t uid,euid,suid,fsuid;
	gid_t gid,egid,sgid,fsgid;
	int ngroups;
	gid_t	groups[NGROUPS];
	kernel_cap_t   cap_effective, cap_inheritable, cap_permitted;
	int keep_capabilities:1;
	struct user_struct *user;
/* limits */
	struct rlimit rlim[RLIM_NLIMITS];
	unsigned short used_math;
	char comm[16];
/* file system info */
	int link_count, total_link_count;
	struct tty_struct *tty; /* NULL if no tty */
	unsigned int locks; /* How many file locks are being held */
/* ipc stuff */
	struct sem_undo *semundo;
	struct sem_queue *semsleeping;
/* CPU-specific state of this task */
	struct thread_struct thread;
/* filesystem information */
	struct fs_struct *fs;
/* open file information */
	struct files_struct *files;
/* namespace */
	struct namespace *namespace;
/* signal handlers */
	spinlock_t sigmask_lock;	/* Protects signal and blocked */
	struct signal_struct *sig;

	sigset_t blocked;
	struct sigpending pending;

	unsigned long sas_ss_sp;
	size_t sas_ss_size;
	int (*notifier)(void *priv);
	void *notifier_data;
	sigset_t *notifier_mask;
	
/* Thread group tracking */
   	u32 parent_exec_id;
   	u32 self_exec_id;
/* Protection of (de-)allocation: mm, files, fs, tty */
	spinlock_t alloc_lock;

/* journalling filesystem info */
	void *journal_info;
};

/*
 * Per process flags
 */
#define PF_ALIGNWARN	0x00000001	/* Print alignment warning msgs */
					/* Not implemented yet, only for 486*/
#define PF_STARTING	0x00000002	/* being created */
#define PF_EXITING	0x00000004	/* getting shut down */
#define PF_FORKNOEXEC	0x00000040	/* forked but didn't exec */
#define PF_SUPERPRIV	0x00000100	/* used super-user privileges */
#define PF_DUMPCORE	0x00000200	/* dumped core */
#define PF_SIGNALED	0x00000400	/* killed by a signal */
#define PF_MEMALLOC	0x00000800	/* Allocating memory */
#define PF_MEMDIE	0x00001000	/* Killed for out-of-memory */
#define PF_FREE_PAGES	0x00002000	/* per process page freeing */
#define PF_NOIO		0x00004000	/* avoid generating further I/O */

#define PF_USEDFPU	0x00100000	/* task used FPU this quantum (SMP) */

/*
 * Ptrace flags
 */

#define PT_PTRACED	0x00000001
#define PT_SYSCALLTRACE	0x00000002	/* T if syscall_trace is +1 for ptrace() */
#define PT_DTRACE	0x00000004	/* delayed trace (used on m68k, i386) */
#define PT_TRACESYSGOOD	0x00000008
#define PT_PTRACE_CAP	0x00000010	/* ptracer can follow suid-exec */

/*
 * Limit the stack by to some sane default: root can always
 * increase this limit if needed..  8MB seems reasonable.
 */
#define _STK_LIM	(8*1024*1024)

/*
 * RT priorites go from 0 to 99, but internally we max
 * them out at 128 to make it easier to search the
 * scheduler bitmap.
 */
#define MAX_RT_PRIO		128
/*
 * The lower the priority of a process, the more likely it is
 * to run. Priority of a process goes from 0 to 167. The 0-99
 * priority range is allocated to RT tasks, the 128-167 range
 * is for SCHED_OTHER tasks.
 */
#define MAX_PRIO		(MAX_RT_PRIO + 40)

/*
 * Scales user-nice values [ -20 ... 0 ... 19 ]
 * to static priority [ 128 ... 167 (MAX_PRIO-1) ]
 *
 * User-nice value of -20 == static priority 128, and
 * user-nice value 19 == static priority 167. The lower
 * the priority value, the higher the task's priority.
 */
#define NICE_TO_PRIO(n)		(MAX_RT_PRIO + (n) + 20)
#define DEF_USER_NICE		0

/*
 * Default timeslice is 150 msecs, maximum is 300 msecs.
 * Minimum timeslice is 10 msecs.
 *
 * These are the 'tuning knobs' of the scheduler:
 */
#define MIN_TIMESLICE		( 10 * HZ / 1000)
#define MAX_TIMESLICE		(300 * HZ / 1000)
#define CHILD_FORK_PENALTY	95
#define PARENT_FORK_PENALTY	100
#define EXIT_WEIGHT		3
#define PRIO_INTERACTIVE_RATIO	20
#define PRIO_CPU_HOG_RATIO	60
#define PRIO_BONUS_RATIO	70
#define INTERACTIVE_DELTA	3
#define MAX_SLEEP_AVG		(2*HZ)
#define STARVATION_LIMIT	(2*HZ)

#define USER_PRIO(p)		((p)-MAX_RT_PRIO)
#define MAX_USER_PRIO		(USER_PRIO(MAX_PRIO))

/*
 * NICE_TO_TIMESLICE scales nice values [ -20 ... 19 ]
 * to time slice values.
 *
 * The higher a process's priority, the bigger timeslices
 * it gets during one round of execution. But even the lowest
 * priority process gets MIN_TIMESLICE worth of execution time.
 */

#define NICE_TO_TIMESLICE(n) (MIN_TIMESLICE + \
	((MAX_TIMESLICE - MIN_TIMESLICE) * (19-(n))) / 39)

extern void set_cpus_allowed(task_t *p, unsigned long new_mask);
extern void set_user_nice(task_t *p, long nice);
asmlinkage long sys_sched_yield(void);
#define yield() sys_sched_yield()

/*
 * The default (Linux) execution domain.
 */
extern struct exec_domain	default_exec_domain;

#ifndef INIT_TASK_SIZE
# define INIT_TASK_SIZE	2048*sizeof(long)
#endif

union task_union {
	struct task_struct task;
	unsigned long stack[INIT_TASK_SIZE/sizeof(long)];
};

extern union task_union init_task_union;

extern struct   mm_struct init_mm;
extern struct task_struct *init_tasks[NR_CPUS];

/* PID hashing. (shouldnt this be dynamic?) */
#define PIDHASH_SZ (4096 >> 2)
extern struct task_struct *pidhash[PIDHASH_SZ];

#define pid_hashfn(x)	((((x) >> 8) ^ (x)) & (PIDHASH_SZ - 1))

static inline void hash_pid(struct task_struct *p)
{
	struct task_struct **htable = &pidhash[pid_hashfn(p->pid)];

	if((p->pidhash_next = *htable) != NULL)
		(*htable)->pidhash_pprev = &p->pidhash_next;
	*htable = p;
	p->pidhash_pprev = htable;
}

static inline void unhash_pid(struct task_struct *p)
{
	if(p->pidhash_next)
		p->pidhash_next->pidhash_pprev = p->pidhash_pprev;
	*p->pidhash_pprev = p->pidhash_next;
}

static inline struct task_struct *find_task_by_pid(int pid)
{
	struct task_struct *p, **htable = &pidhash[pid_hashfn(pid)];

	for(p = *htable; p && p->pid != pid; p = p->pidhash_next)
		;

	return p;
}

/* per-UID process charging. */
extern struct user_struct * alloc_uid(uid_t);
extern void free_uid(struct user_struct *);

#include <asm/current.h>

extern unsigned long volatile jiffies;
extern unsigned long itimer_ticks;
extern unsigned long itimer_next;
extern struct timeval xtime;
extern void do_timer(struct pt_regs *);

extern unsigned int * prof_buffer;
extern unsigned long prof_len;
extern unsigned long prof_shift;

#define CURRENT_TIME (xtime.tv_sec)

extern void FASTCALL(__wake_up(wait_queue_head_t *q, unsigned int mode, int nr));
extern void FASTCALL(__wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr));
extern void FASTCALL(sleep_on(wait_queue_head_t *q));
extern long FASTCALL(sleep_on_timeout(wait_queue_head_t *q,
				      signed long timeout));
extern void FASTCALL(interruptible_sleep_on(wait_queue_head_t *q));
extern long FASTCALL(interruptible_sleep_on_timeout(wait_queue_head_t *q,
						    signed long timeout));
extern int FASTCALL(wake_up_process(struct task_struct * tsk));
extern void FASTCALL(wake_up_forked_process(struct task_struct * tsk));

#define wake_up(x)			__wake_up((x),TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 1)
#define wake_up_nr(x, nr)		__wake_up((x),TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, nr)
#define wake_up_all(x)			__wake_up((x),TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 0)
#define wake_up_sync(x)			__wake_up_sync((x),TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, 1)
#define wake_up_sync_nr(x, nr)		__wake_up_sync((x),TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, nr)
#define wake_up_interruptible(x)	__wake_up((x),TASK_INTERRUPTIBLE, 1)
#define wake_up_interruptible_nr(x, nr)	__wake_up((x),TASK_INTERRUPTIBLE, nr)
#define wake_up_interruptible_all(x)	__wake_up((x),TASK_INTERRUPTIBLE, 0)
#define wake_up_interruptible_sync(x)	__wake_up_sync((x),TASK_INTERRUPTIBLE, 1)
#define wake_up_interruptible_sync_nr(x) __wake_up_sync((x),TASK_INTERRUPTIBLE,  nr)
asmlinkage long sys_wait4(pid_t pid,unsigned int * stat_addr, int options, struct rusage * ru);

extern int in_group_p(gid_t);
extern int in_egroup_p(gid_t);

extern void proc_caches_init(void);
extern void flush_signals(struct task_struct *);
extern void flush_signal_handlers(struct task_struct *);
extern void sig_exit(int, int, struct siginfo *);
extern int dequeue_signal(sigset_t *, siginfo_t *);
extern void block_all_signals(int (*notifier)(void *priv), void *priv,
			      sigset_t *mask);
extern void unblock_all_signals(void);
extern int send_sig_info(int, struct siginfo *, struct task_struct *);
extern int force_sig_info(int, struct siginfo *, struct task_struct *);
extern int kill_pg_info(int, struct siginfo *, pid_t);
extern int kill_sl_info(int, struct siginfo *, pid_t);
extern int kill_proc_info(int, struct siginfo *, pid_t);
extern void notify_parent(struct task_struct *, int);
extern void do_notify_parent(struct task_struct *, int);
extern void force_sig(int, struct task_struct *);
extern int send_sig(int, struct task_struct *, int);
extern int kill_pg(pid_t, int, int);
extern int kill_sl(pid_t, int, int);
extern int kill_proc(pid_t, int, int);
extern int do_sigaction(int, const struct k_sigaction *, struct k_sigaction *);
extern int do_sigaltstack(const stack_t *, stack_t *, unsigned long);

static inline int signal_pending(struct task_struct *p)
{
	return (p->work.sigpending != 0);
}
  
static inline int need_resched(void)
{
	return unlikely(current->work.need_resched != 0);
}

static inline void cond_resched(void)
{
	if (need_resched())
		schedule();
}

/*
 * Re-calculate pending state from the set of locally pending
 * signals, globally pending signals, and blocked signals.
 */
static inline int has_pending_signals(sigset_t *signal, sigset_t *blocked)
{
	unsigned long ready;
	long i;

	switch (_NSIG_WORDS) {
	default:
		for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;)
			ready |= signal->sig[i] &~ blocked->sig[i];
		break;

	case 4: ready  = signal->sig[3] &~ blocked->sig[3];
		ready |= signal->sig[2] &~ blocked->sig[2];
		ready |= signal->sig[1] &~ blocked->sig[1];
		ready |= signal->sig[0] &~ blocked->sig[0];
		break;

	case 2: ready  = signal->sig[1] &~ blocked->sig[1];
		ready |= signal->sig[0] &~ blocked->sig[0];
		break;

	case 1: ready  = signal->sig[0] &~ blocked->sig[0];
	}
	return ready !=	0;
}

/* Reevaluate whether the task has signals pending delivery.
   This is required every time the blocked sigset_t changes.
   All callers should have t->sigmask_lock.  */

static inline void recalc_sigpending(struct task_struct *t)
{
	t->work.sigpending = has_pending_signals(&t->pending.signal, &t->blocked);
}

/* True if we are on the alternate signal stack.  */

static inline int on_sig_stack(unsigned long sp)
{
	return (sp - current->sas_ss_sp < current->sas_ss_size);
}

static inline int sas_ss_flags(unsigned long sp)
{
	return (current->sas_ss_size == 0 ? SS_DISABLE
		: on_sig_stack(sp) ? SS_ONSTACK : 0);
}

extern int request_irq(unsigned int,
		       void (*handler)(int, void *, struct pt_regs *),
		       unsigned long, const char *, void *);
extern void free_irq(unsigned int, void *);

/*
 * This has now become a routine instead of a macro, it sets a flag if
 * it returns true (to do BSD-style accounting where the process is flagged
 * if it uses root privs). The implication of this is that you should do
 * normal permissions checks first, and check suser() last.
 *
 * [Dec 1997 -- Chris Evans]
 * For correctness, the above considerations need to be extended to
 * fsuser(). This is done, along with moving fsuser() checks to be
 * last.
 *
 * These will be removed, but in the mean time, when the SECURE_NOROOT 
 * flag is set, uids don't grant privilege.
 */
static inline int suser(void)
{
	if (!issecure(SECURE_NOROOT) && current->euid == 0) { 
		current->flags |= PF_SUPERPRIV;
		return 1;
	}
	return 0;
}

static inline int fsuser(void)
{
	if (!issecure(SECURE_NOROOT) && current->fsuid == 0) {
		current->flags |= PF_SUPERPRIV;
		return 1;
	}
	return 0;
}

/*
 * capable() checks for a particular capability.  
 * New privilege checks should use this interface, rather than suser() or
 * fsuser(). See include/linux/capability.h for defined capabilities.
 */

static inline int capable(int cap)
{
#if 1 /* ok now */
	if (cap_raised(current->cap_effective, cap))
#else
	if (cap_is_fs_cap(cap) ? current->fsuid == 0 : current->euid == 0)
#endif
	{
		current->flags |= PF_SUPERPRIV;
		return 1;
	}
	return 0;
}

/*
 * Routines for handling mm_structs
 */
extern struct mm_struct * mm_alloc(void);

extern struct mm_struct * start_lazy_tlb(void);
extern void end_lazy_tlb(struct mm_struct *mm);

/* mmdrop drops the mm and the page tables */
extern inline void FASTCALL(__mmdrop(struct mm_struct *));
static inline void mmdrop(struct mm_struct * mm)
{
	if (atomic_dec_and_test(&mm->mm_count))
		__mmdrop(mm);
}

/* mmput gets rid of the mappings and all user-space */
extern void mmput(struct mm_struct *);
/* Remove the current tasks stale references to the old mm_struct */
extern void mm_release(void);

/*
 * Routines for handling the fd arrays
 */
extern struct file ** alloc_fd_array(int);
extern int expand_fd_array(struct files_struct *, int nr);
extern void free_fd_array(struct file **, int);

extern fd_set *alloc_fdset(int);
extern int expand_fdset(struct files_struct *, int nr);
extern void free_fdset(fd_set *, int);

extern int  copy_thread(int, unsigned long, unsigned long, unsigned long, struct task_struct *, struct pt_regs *);
extern void flush_thread(void);
extern void exit_thread(void);

extern void exit_mm(struct task_struct *);
extern void exit_files(struct task_struct *);
extern void exit_sighand(struct task_struct *);

extern void reparent_to_init(void);
extern void daemonize(void);
extern task_t *child_reaper;

extern int do_execve(char *, char **, char **, struct pt_regs *);
extern int do_fork(unsigned long, unsigned long, struct pt_regs *, unsigned long);

extern void FASTCALL(add_wait_queue(wait_queue_head_t *q, wait_queue_t * wait));
extern void FASTCALL(add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t * wait));
extern void FASTCALL(remove_wait_queue(wait_queue_head_t *q, wait_queue_t * wait));

extern void wait_task_inactive(task_t * p);
extern void kick_if_running(task_t * p);

#define __wait_event(wq, condition) 					\
do {									\
	wait_queue_t __wait;						\
	init_waitqueue_entry(&__wait, current);				\
									\
	add_wait_queue(&wq, &__wait);					\
	for (;;) {							\
		set_current_state(TASK_UNINTERRUPTIBLE);		\
		if (condition)						\
			break;						\
		schedule();						\
	}								\
	current->state = TASK_RUNNING;					\
	remove_wait_queue(&wq, &__wait);				\
} while (0)

#define wait_event(wq, condition) 					\
do {									\
	if (condition)	 						\
		break;							\
	__wait_event(wq, condition);					\
} while (0)

#define __wait_event_interruptible(wq, condition, ret)			\
do {									\
	wait_queue_t __wait;						\
	init_waitqueue_entry(&__wait, current);				\
									\
	add_wait_queue(&wq, &__wait);					\
	for (;;) {							\
		set_current_state(TASK_INTERRUPTIBLE);			\
		if (condition)						\
			break;						\
		if (!signal_pending(current)) {				\
			schedule();					\
			continue;					\
		}							\
		ret = -ERESTARTSYS;					\
		break;							\
	}								\
	current->state = TASK_RUNNING;					\
	remove_wait_queue(&wq, &__wait);				\
} while (0)
	
#define wait_event_interruptible(wq, condition)				\
({									\
	int __ret = 0;							\
	if (!(condition))						\
		__wait_event_interruptible(wq, condition, __ret);	\
	__ret;								\
})

#define REMOVE_LINKS(p) do { \
	(p)->next_task->prev_task = (p)->prev_task; \
	(p)->prev_task->next_task = (p)->next_task; \
	if ((p)->p_osptr) \
		(p)->p_osptr->p_ysptr = (p)->p_ysptr; \
	if ((p)->p_ysptr) \
		(p)->p_ysptr->p_osptr = (p)->p_osptr; \
	else \
		(p)->p_pptr->p_cptr = (p)->p_osptr; \
	} while (0)

#define SET_LINKS(p) do { \
	(p)->next_task = &init_task; \
	(p)->prev_task = init_task.prev_task; \
	init_task.prev_task->next_task = (p); \
	init_task.prev_task = (p); \
	(p)->p_ysptr = NULL; \
	if (((p)->p_osptr = (p)->p_pptr->p_cptr) != NULL) \
		(p)->p_osptr->p_ysptr = p; \
	(p)->p_pptr->p_cptr = p; \
	} while (0)

#define for_each_task(p) \
	for (p = &init_task ; (p = p->next_task) != &init_task ; )

#define for_each_thread(task) \
	for (task = next_thread(current) ; task != current ; task = next_thread(task))

#define next_thread(p) \
	list_entry((p)->thread_group.next, struct task_struct, thread_group)

#define thread_group_leader(p)	(p->pid == p->tgid)

static inline void unhash_process(struct task_struct *p)
{
	write_lock_irq(&tasklist_lock);
	nr_threads--;
	unhash_pid(p);
	REMOVE_LINKS(p);
	list_del(&p->thread_group);
	write_unlock_irq(&tasklist_lock);
}

/* Protects ->fs, ->files, ->mm, and synchronises with wait4().  Nests inside tasklist_lock */
static inline void task_lock(struct task_struct *p)
{
	spin_lock(&p->alloc_lock);
}

static inline void task_unlock(struct task_struct *p)
{
	spin_unlock(&p->alloc_lock);
}

/* write full pathname into buffer and return start of pathname */
static inline char * d_path(struct dentry *dentry, struct vfsmount *vfsmnt,
				char *buf, int buflen)
{
	char *res;
	struct vfsmount *rootmnt;
	struct dentry *root;
	read_lock(&current->fs->lock);
	rootmnt = mntget(current->fs->rootmnt);
	root = dget(current->fs->root);
	read_unlock(&current->fs->lock);
	spin_lock(&dcache_lock);
	res = __d_path(dentry, vfsmnt, root, rootmnt, buf, buflen);
	spin_unlock(&dcache_lock);
	dput(root);
	mntput(rootmnt);
	return res;
}

#endif /* __KERNEL__ */

#endif