include/linux/sched.h

   1 #ifndef _LINUX_SCHED_H
   2 #define _LINUX_SCHED_H
   3
   4 #include <asm/param.h>  /* for HZ */
   5
   6 extern unsigned long event;
   7
   8 #include <linux/binfmts.h>
   9 #include <linux/personality.h>
  10 #include <linux/tasks.h>
  11 #include <linux/kernel.h>
  12 #include <linux/types.h>
  13 #include <linux/times.h>
  14 #include <linux/timex.h>
  15
  16 #include <asm/system.h>
  17 #include <asm/semaphore.h>
  18 #include <asm/page.h>
  19
  20 #include <linux/smp.h>
  21 #include <linux/tty.h>
  22 #include <linux/sem.h>
  23 #include <linux/signal.h>
  24 #include <linux/securebits.h>
  25
  26 /*
  27  * cloning flags:
  28  */
  29 #define CSIGNAL         0x000000ff      /* signal mask to be sent at exit */
  30 #define CLONE_VM        0x00000100      /* set if VM shared between processes */
  31 #define CLONE_FS        0x00000200      /* set if fs info shared between processes */
  32 #define CLONE_FILES     0x00000400      /* set if open files shared between processes */
  33 #define CLONE_SIGHAND   0x00000800      /* set if signal handlers shared */
  34 #define CLONE_PID       0x00001000      /* set if pid shared */
  35 #define CLONE_PTRACE    0x00002000      /* set if we want to let tracing continue on the child too */
  36
  37 /*
  38  * These are the constant used to fake the fixed-point load-average
  39  * counting. Some notes:
  40  *  - 11 bit fractions expand to 22 bits by the multiplies: this gives
  41  *    a load-average precision of 10 bits integer + 11 bits fractional
  42  *  - if you want to count load-averages more often, you need more
  43  *    precision, or rounding will get you. With 2-second counting freq,
  44  *    the EXP_n values would be 1981, 2034 and 2043 if still using only
  45  *    11 bit fractions.
  46  */
  47 extern unsigned long avenrun[];         /* Load averages */
  48
  49 #define FSHIFT          11              /* nr of bits of precision */
  50 #define FIXED_1         (1<<FSHIFT)     /* 1.0 as fixed-point */
  51 #define LOAD_FREQ       (5*HZ)          /* 5 sec intervals */
  52 #define EXP_1           1884            /* 1/exp(5sec/1min) as fixed-point */
  53 #define EXP_5           2014            /* 1/exp(5sec/5min) */
  54 #define EXP_15          2037            /* 1/exp(5sec/15min) */
  55
  56 #define CALC_LOAD(load,exp,n) \
  57         load *= exp; \
  58         load += n*(FIXED_1-exp); \
  59         load >>= FSHIFT;
  60
  61 #define CT_TO_SECS(x)   ((x) / HZ)
  62 #define CT_TO_USECS(x)  (((x) % HZ) * 1000000/HZ)
  63
  64 extern int nr_running, nr_tasks;
  65 extern int last_pid;
  66
  67 #include <linux/fs.h>
  68 #include <linux/time.h>
  69 #include <linux/param.h>
  70 #include <linux/resource.h>
  71 #include <linux/timer.h>
  72
  73 #include <asm/processor.h>
  74
  75 #define TASK_RUNNING            0
  76 #define TASK_INTERRUPTIBLE      1
  77 #define TASK_UNINTERRUPTIBLE    2
  78 #define TASK_ZOMBIE             4
  79 #define TASK_STOPPED            8
  80 #define TASK_SWAPPING           16
  81
  82 /*
  83  * Scheduling policies
  84  */
  85 #define SCHED_OTHER             0
  86 #define SCHED_FIFO              1
  87 #define SCHED_RR                2
  88
  89 /*
  90  * This is an additional bit set when we want to
  91  * yield the CPU for one re-schedule..
  92  */
  93 #define SCHED_YIELD             0x10
  94
  95 struct sched_param {
  96         int sched_priority;
  97 };
  98
  99 #ifndef NULL
 100 #define NULL ((void *) 0)
 101 #endif
 102
 103 #ifdef __KERNEL__
 104
 105 #include <asm/spinlock.h>
 106
 107 /*
 108  * This serializes "schedule()" and also protects
 109  * the run-queue from deletions/modifications (but
 110  * _adding_ to the beginning of the run-queue has
 111  * a separate lock).
 112  */
 113 extern rwlock_t tasklist_lock;
 114 extern spinlock_t scheduler_lock;
 115
 116 extern void sched_init(void);
 117 extern void show_state(void);
 118 extern void trap_init(void);
 119
 120 #define MAX_SCHEDULE_TIMEOUT    LONG_MAX
 121 extern signed long FASTCALL(schedule_timeout(signed long timeout));
 122 asmlinkage void schedule(void);
 123
 124 /*
 125  * Open file table structure
 126  */
 127 struct files_struct {
 128         atomic_t count;
 129         int max_fds;
 130         struct file ** fd;      /* current fd array */
 131         fd_set close_on_exec;
 132         fd_set open_fds;
 133 };
 134
 135 #define INIT_FILES { \
 136         ATOMIC_INIT(1), \
 137         NR_OPEN, \
 138         &init_fd_array[0], \
 139         { { 0, } }, \
 140         { { 0, } } \
 141 }
 142
 143 struct fs_struct {
 144         atomic_t count;
 145         int umask;
 146         struct dentry * root, * pwd;
 147 };
 148
 149 #define INIT_FS { \
 150         ATOMIC_INIT(1), \
 151         0022, \
 152         NULL, NULL \
 153 }
 154
 155 /* Maximum number of active map areas.. This is a random (large) number */
 156 #define MAX_MAP_COUNT   (65536)
 157
 158 struct mm_struct {
 159         struct vm_area_struct *mmap, *mmap_cache;
 160         pgd_t * pgd;
 161         atomic_t count;
 162         int map_count;
 163         struct semaphore mmap_sem;
 164         unsigned long context;
 165         unsigned long start_code, end_code, start_data, end_data;
 166         unsigned long start_brk, brk, start_stack;
 167         unsigned long arg_start, arg_end, env_start, env_end;
 168         unsigned long rss, total_vm, locked_vm;
 169         unsigned long def_flags;
 170         unsigned long cpu_vm_mask;
 171         /*
 172          * This is an architecture-specific pointer: the portable
 173          * part of Linux does not know about any segments.
 174          */
 175         void * segments;
 176 };
 177
 178 #define INIT_MM {                                       \
 179                 &init_mmap, NULL, swapper_pg_dir,       \
 180                 ATOMIC_INIT(1), 1,                      \
 181                 MUTEX,                                  \
 182                 0,                                      \
 183                 0, 0, 0, 0,                             \
 184                 0, 0, 0,                                \
 185                 0, 0, 0, 0,                             \
 186                 0, 0, 0,                                \
 187                 0, 0, NULL }
 188
 189 struct signal_struct {
 190         atomic_t                count;
 191         struct k_sigaction      action[_NSIG];
 192         spinlock_t              siglock;
 193 };
 194
 195
 196 #define INIT_SIGNALS { \
 197                 ATOMIC_INIT(1), \
 198                 { {{0,}}, }, \
 199                 SPIN_LOCK_UNLOCKED }
 200
 201 /*
 202  * Some day this will be a full-fledged user tracking system..
 203  * Right now it is only used to track how many processes a
 204  * user has, but it has the potential to track memory usage etc.
 205  */
 206 struct user_struct;
 207
 208 struct task_struct {
 209 /* these are hardcoded - don't touch */
 210         volatile long state;    /* -1 unrunnable, 0 runnable, >0 stopped */
 211         unsigned long flags;    /* per process flags, defined below */
 212         int sigpending;
 213         mm_segment_t addr_limit;        /* thread address space:
 214                                                 0-0xBFFFFFFF for user-thead
 215                                                 0-0xFFFFFFFF for kernel-thread
 216                                          */
 217         struct exec_domain *exec_domain;
 218         long need_resched;
 219
 220 /* various fields */
 221         long counter;
 222         long priority;
 223         cycles_t avg_slice;
 224 /* SMP and runqueue state */
 225         int has_cpu;
 226         int processor;
 227         int last_processor;
 228         int lock_depth;         /* Lock depth. We can context switch in and out of holding a syscall kernel lock... */
 229         struct task_struct *next_task, *prev_task;
 230         struct task_struct *next_run,  *prev_run;
 231
 232 /* task state */
 233         struct linux_binfmt *binfmt;
 234         int exit_code, exit_signal;
 235         int pdeath_signal;  /*  The signal sent when the parent dies  */
 236         /* ??? */
 237         unsigned long personality;
 238         int dumpable:1;
 239         int did_exec:1;
 240         pid_t pid;
 241         pid_t pgrp;
 242         pid_t tty_old_pgrp;
 243         pid_t session;
 244         /* boolean value for session group leader */
 245         int leader;
 246         /*
 247          * pointers to (original) parent process, youngest child, younger sibling,
 248          * older sibling, respectively.  (p->father can be replaced with
 249          * p->p_pptr->pid)
 250          */
 251         struct task_struct *p_opptr, *p_pptr, *p_cptr, *p_ysptr, *p_osptr;
 252
 253         /* PID hash table linkage. */
 254         struct task_struct *pidhash_next;
 255         struct task_struct **pidhash_pprev;
 256
 257         /* Pointer to task[] array linkage. */
 258         struct task_struct **tarray_ptr;
 259
 260         struct wait_queue *wait_chldexit, *vfork_sleep; /* for wait4()/vfork */
 261
 262         unsigned long policy, rt_priority;
 263         unsigned long it_real_value, it_prof_value, it_virt_value;
 264         unsigned long it_real_incr, it_prof_incr, it_virt_incr;
 265         struct timer_list real_timer;
 266         struct tms times;
 267         unsigned long start_time;
 268         long per_cpu_utime[NR_CPUS], per_cpu_stime[NR_CPUS];
 269 /* mm fault and swap info: this can arguably be seen as either mm-specific or thread-specific */
 270         unsigned long min_flt, maj_flt, nswap, cmin_flt, cmaj_flt, cnswap;
 271         int swappable:1;
 272         int trashing_memory:1;
 273         unsigned long swap_address;
 274         unsigned long old_maj_flt;      /* old value of maj_flt */
 275         unsigned long dec_flt;          /* page fault count of the last time */
 276         unsigned long swap_cnt;         /* number of pages to swap on next pass */
 277 /* process credentials */
 278         uid_t uid,euid,suid,fsuid;
 279         gid_t gid,egid,sgid,fsgid;
 280         int ngroups;
 281         gid_t   groups[NGROUPS];
 282         kernel_cap_t   cap_effective, cap_inheritable, cap_permitted;
 283         struct user_struct *user;
 284 /* limits */
 285         struct rlimit rlim[RLIM_NLIMITS];
 286         unsigned short used_math;
 287         char comm[16];
 288 /* file system info */
 289         int link_count;
 290         struct tty_struct *tty; /* NULL if no tty */
 291 /* ipc stuff */
 292         struct sem_undo *semundo;
 293         struct sem_queue *semsleeping;
 294 /* tss for this task */
 295         struct thread_struct tss;
 296 /* filesystem information */
 297         struct fs_struct *fs;
 298 /* open file information */
 299         struct files_struct *files;
 300 /* memory management info */
 301         struct mm_struct *mm;
 302
 303 /* signal handlers */
 304         spinlock_t sigmask_lock;        /* Protects signal and blocked */
 305         struct signal_struct *sig;
 306         sigset_t signal, blocked;
 307         struct signal_queue *sigqueue, **sigqueue_tail;
 308         unsigned long sas_ss_sp;
 309         size_t sas_ss_size;
 310 };
 311
 312 /*
 313  * Per process flags
 314  */
 315 #define PF_ALIGNWARN    0x00000001      /* Print alignment warning msgs */
 316                                         /* Not implemented yet, only for 486*/
 317 #define PF_STARTING     0x00000002      /* being created */
 318 #define PF_EXITING      0x00000004      /* getting shut down */
 319 #define PF_PTRACED      0x00000010      /* set if ptrace (0) has been called */
 320 #define PF_TRACESYS     0x00000020      /* tracing system calls */
 321 #define PF_FORKNOEXEC   0x00000040      /* forked but didn't exec */
 322 #define PF_SUPERPRIV    0x00000100      /* used super-user privileges */
 323 #define PF_DUMPCORE     0x00000200      /* dumped core */
 324 #define PF_SIGNALED     0x00000400      /* killed by a signal */
 325 #define PF_MEMALLOC     0x00000800      /* Allocating memory */
 326
 327 #define PF_USEDFPU      0x00100000      /* task used FPU this quantum (SMP) */
 328 #define PF_DTRACE       0x00200000      /* delayed trace (used on m68k, i386) */
 329
 330 /*
 331  * Limit the stack by to some sane default: root can always
 332  * increase this limit if needed..  8MB seems reasonable.
 333  */
 334 #define _STK_LIM        (8*1024*1024)
 335
 336 #define DEF_PRIORITY    (20*HZ/100)     /* 200 ms time slices */
 337
 338 /*
 339  *  INIT_TASK is used to set up the first task table, touch at
 340  * your own risk!. Base=0, limit=0x1fffff (=2MB)
 341  */
 342 #define INIT_TASK \
 343 /* state etc */ { 0,0,0,KERNEL_DS,&default_exec_domain,0, \
 344 /* counter */   DEF_PRIORITY,DEF_PRIORITY,0, \
 345 /* SMP */       0,0,0,-1, \
 346 /* schedlink */ &init_task,&init_task, &init_task, &init_task, \
 347 /* binfmt */    NULL, \
 348 /* ec,brk... */ 0,0,0,0,0,0, \
 349 /* pid etc.. */ 0,0,0,0,0, \
 350 /* proc links*/ &init_task,&init_task,NULL,NULL,NULL, \
 351 /* pidhash */   NULL, NULL, \
 352 /* tarray */    &task[0], \
 353 /* chld wait */ NULL, NULL, \
 354 /* timeout */   SCHED_OTHER,0,0,0,0,0,0,0, \
 355 /* timer */     { NULL, NULL, 0, 0, it_real_fn }, \
 356 /* utime */     {0,0,0,0},0, \
 357 /* per CPU times */ {0, }, {0, }, \
 358 /* flt */       0,0,0,0,0,0, \
 359 /* swp */       0,0,0,0,0,0, \
 360 /* process credentials */                                       \
 361 /* uid etc */   0,0,0,0,0,0,0,0,                                \
 362 /* suppl grps*/ 0, {0,},                                        \
 363 /* caps */      CAP_INIT_EFF_SET,CAP_INIT_INH_SET,CAP_FULL_SET, \
 364 /* user */      NULL,                                           \
 365 /* rlimits */   INIT_RLIMITS, \
 366 /* math */      0, \
 367 /* comm */      "swapper", \
 368 /* fs info */   0,NULL, \
 369 /* ipc */       NULL, NULL, \
 370 /* tss */       INIT_TSS, \
 371 /* fs */        &init_fs, \
 372 /* files */     &init_files, \
 373 /* mm */        &init_mm, \
 374 /* signals */   SPIN_LOCK_UNLOCKED, &init_signals, {{0}}, {{0}}, NULL, &init_task.sigqueue, 0, 0, \
 375 }
 376
 377 union task_union {
 378         struct task_struct task;
 379         unsigned long stack[2048];
 380 };
 381
 382 extern union task_union init_task_union;
 383
 384 extern struct   mm_struct init_mm;
 385 extern struct task_struct *task[NR_TASKS];
 386
 387 extern struct task_struct **tarray_freelist;
 388 extern spinlock_t taskslot_lock;
 389
 390 extern __inline__ void add_free_taskslot(struct task_struct **t)
 391 {
 392         spin_lock(&taskslot_lock);
 393         *t = (struct task_struct *) tarray_freelist;
 394         tarray_freelist = t;
 395         spin_unlock(&taskslot_lock);
 396 }
 397
 398 extern __inline__ struct task_struct **get_free_taskslot(void)
 399 {
 400         struct task_struct **tslot;
 401
 402         spin_lock(&taskslot_lock);
 403         if((tslot = tarray_freelist) != NULL)
 404                 tarray_freelist = (struct task_struct **) *tslot;
 405         spin_unlock(&taskslot_lock);
 406
 407         return tslot;
 408 }
 409
 410 /* PID hashing. */
 411 #define PIDHASH_SZ (NR_TASKS >> 2)
 412 extern struct task_struct *pidhash[PIDHASH_SZ];
 413
 414 #define pid_hashfn(x)   ((((x) >> 8) ^ (x)) & (PIDHASH_SZ - 1))
 415
 416 extern __inline__ void hash_pid(struct task_struct *p)
 417 {
 418         struct task_struct **htable = &pidhash[pid_hashfn(p->pid)];
 419
 420         if((p->pidhash_next = *htable) != NULL)
 421                 (*htable)->pidhash_pprev = &p->pidhash_next;
 422         *htable = p;
 423         p->pidhash_pprev = htable;
 424 }
 425
 426 extern __inline__ void unhash_pid(struct task_struct *p)
 427 {
 428         if(p->pidhash_next)
 429                 p->pidhash_next->pidhash_pprev = p->pidhash_pprev;
 430         *p->pidhash_pprev = p->pidhash_next;
 431 }
 432
 433 extern __inline__ struct task_struct *find_task_by_pid(int pid)
 434 {
 435         struct task_struct *p, **htable = &pidhash[pid_hashfn(pid)];
 436
 437         for(p = *htable; p && p->pid != pid; p = p->pidhash_next)
 438                 ;
 439
 440         return p;
 441 }
 442
 443 /* per-UID process charging. */
 444 extern int alloc_uid(struct task_struct *p);
 445 void free_uid(struct task_struct *p);
 446
 447 #include <asm/current.h>
 448
 449 extern unsigned long volatile jiffies;
 450 extern unsigned long itimer_ticks;
 451 extern unsigned long itimer_next;
 452 extern struct timeval xtime;
 453 extern void do_timer(struct pt_regs *);
 454
 455 extern unsigned int * prof_buffer;
 456 extern unsigned long prof_len;
 457 extern unsigned long prof_shift;
 458
 459 #define CURRENT_TIME (xtime.tv_sec)
 460
 461 extern void FASTCALL(__wake_up(struct wait_queue ** p, unsigned int mode));
 462 extern void FASTCALL(sleep_on(struct wait_queue ** p));
 463 extern long FASTCALL(sleep_on_timeout(struct wait_queue ** p,
 464                                       signed long timeout));
 465 extern void FASTCALL(interruptible_sleep_on(struct wait_queue ** p));
 466 extern long FASTCALL(interruptible_sleep_on_timeout(struct wait_queue ** p,
 467                                                     signed long timeout));
 468 extern void FASTCALL(wake_up_process(struct task_struct * tsk));
 469
 470 #define wake_up(x)                      __wake_up((x),TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE)
 471 #define wake_up_interruptible(x)        __wake_up((x),TASK_INTERRUPTIBLE)
 472
 473 extern int in_group_p(gid_t grp);
 474
 475 extern void flush_signals(struct task_struct *);
 476 extern void flush_signal_handlers(struct task_struct *);
 477 extern int dequeue_signal(sigset_t *block, siginfo_t *);
 478 extern int send_sig_info(int, struct siginfo *info, struct task_struct *);
 479 extern int force_sig_info(int, struct siginfo *info, struct task_struct *);
 480 extern int kill_pg_info(int, struct siginfo *info, pid_t);
 481 extern int kill_sl_info(int, struct siginfo *info, pid_t);
 482 extern int kill_proc_info(int, struct siginfo *info, pid_t);
 483 extern int kill_something_info(int, struct siginfo *info, int);
 484 extern void notify_parent(struct task_struct * tsk, int);
 485 extern void force_sig(int sig, struct task_struct * p);
 486 extern int send_sig(int sig, struct task_struct * p, int priv);
 487 extern int kill_pg(pid_t, int, int);
 488 extern int kill_sl(pid_t, int, int);
 489 extern int kill_proc(pid_t, int, int);
 490 extern int do_sigaction(int sig, const struct k_sigaction *act,
 491                         struct k_sigaction *oact);
 492 extern int do_sigaltstack(const stack_t *ss, stack_t *oss, unsigned long sp);
 493
 494 extern inline int signal_pending(struct task_struct *p)
 495 {
 496         return (p->sigpending != 0);
 497 }
 498
 499 /* Reevaluate whether the task has signals pending delivery.
 500    This is required every time the blocked sigset_t changes.
 501    All callers should have t->sigmask_lock.  */
 502
 503 static inline void recalc_sigpending(struct task_struct *t)
 504 {
 505         unsigned long ready;
 506         long i;
 507
 508         switch (_NSIG_WORDS) {
 509         default:
 510                 for (i = _NSIG_WORDS, ready = 0; --i >= 0 ;)
 511                         ready |= t->signal.sig[i] &~ t->blocked.sig[i];
 512                 break;
 513
 514         case 4: ready  = t->signal.sig[3] &~ t->blocked.sig[3];
 515                 ready |= t->signal.sig[2] &~ t->blocked.sig[2];
 516                 ready |= t->signal.sig[1] &~ t->blocked.sig[1];
 517                 ready |= t->signal.sig[0] &~ t->blocked.sig[0];
 518                 break;
 519
 520         case 2: ready  = t->signal.sig[1] &~ t->blocked.sig[1];
 521                 ready |= t->signal.sig[0] &~ t->blocked.sig[0];
 522                 break;
 523
 524         case 1: ready  = t->signal.sig[0] &~ t->blocked.sig[0];
 525         }
 526
 527         t->sigpending = (ready != 0);
 528 }
 529
 530 /* True if we are on the alternate signal stack.  */
 531
 532 static inline int on_sig_stack(unsigned long sp)
 533 {
 534         return (sp >= current->sas_ss_sp
 535                 && sp < current->sas_ss_sp + current->sas_ss_size);
 536 }
 537
 538 static inline int sas_ss_flags(unsigned long sp)
 539 {
 540         return (current->sas_ss_size == 0 ? SS_DISABLE
 541                 : on_sig_stack(sp) ? SS_ONSTACK : 0);
 542 }
 543
 544 extern int request_irq(unsigned int irq,
 545                        void (*handler)(int, void *, struct pt_regs *),
 546                        unsigned long flags,
 547                        const char *device,
 548                        void *dev_id);
 549 extern void free_irq(unsigned int irq, void *dev_id);
 550
 551 /*
 552  * This has now become a routine instead of a macro, it sets a flag if
 553  * it returns true (to do BSD-style accounting where the process is flagged
 554  * if it uses root privs). The implication of this is that you should do
 555  * normal permissions checks first, and check suser() last.
 556  *
 557  * [Dec 1997 -- Chris Evans]
 558  * For correctness, the above considerations need to be extended to
 559  * fsuser(). This is done, along with moving fsuser() checks to be
 560  * last.
 561  *
 562  * These will be removed, but in the mean time, when the SECURE_NOROOT
 563  * flag is set, uids don't grant privilege.
 564  */
 565 extern inline int suser(void)
 566 {
 567         if (!issecure(SECURE_NOROOT) && current->euid == 0) {
 568                 current->flags |= PF_SUPERPRIV;
 569                 return 1;
 570         }
 571         return 0;
 572 }
 573
 574 extern inline int fsuser(void)
 575 {
 576         if (!issecure(SECURE_NOROOT) && current->fsuid == 0) {
 577                 current->flags |= PF_SUPERPRIV;
 578                 return 1;
 579         }
 580         return 0;
 581 }
 582
 583 /*
 584  * capable() checks for a particular capability.
 585  * New privilege checks should use this interface, rather than suser() or
 586  * fsuser(). See include/linux/capability.h for defined capabilities.
 587  */
 588
 589 extern inline int capable(int cap)
 590 {
 591 #if 1 /* ok now */
 592         if (cap_raised(current->cap_effective, cap))
 593 #else
 594         if (cap_is_fs_cap(cap) ? current->fsuid == 0 : current->euid == 0)
 595 #endif
 596         {
 597                 current->flags |= PF_SUPERPRIV;
 598                 return 1;
 599         }
 600         return 0;
 601 }
 602
 603 /*
 604  * Routines for handling mm_structs
 605  */
 606 extern struct mm_struct * mm_alloc(void);
 607 static inline void mmget(struct mm_struct * mm)
 608 {
 609         atomic_inc(&mm->count);
 610 }
 611 extern void mmput(struct mm_struct *);
 612
 613 extern int  copy_thread(int, unsigned long, unsigned long, struct task_struct *, struct pt_regs *);
 614 extern void flush_thread(void);
 615 extern void exit_thread(void);
 616
 617 extern void exit_mm(struct task_struct *);
 618 extern void exit_fs(struct task_struct *);
 619 extern void exit_files(struct task_struct *);
 620 extern void exit_sighand(struct task_struct *);
 621
 622 extern int do_execve(char *, char **, char **, struct pt_regs *);
 623 extern int do_fork(unsigned long, unsigned long, struct pt_regs *);
 624
 625 /*
 626  * The wait-queues are circular lists, and you have to be *very* sure
 627  * to keep them correct. Use only these two functions to add/remove
 628  * entries in the queues.
 629  */
 630 extern inline void __add_wait_queue(struct wait_queue ** p, struct wait_queue * wait)
 631 {
 632         wait->next = *p ? : WAIT_QUEUE_HEAD(p);
 633         *p = wait;
 634 }
 635
 636 extern rwlock_t waitqueue_lock;
 637
 638 extern inline void add_wait_queue(struct wait_queue ** p, struct wait_queue * wait)
 639 {
 640         unsigned long flags;
 641
 642         write_lock_irqsave(&waitqueue_lock, flags);
 643         __add_wait_queue(p, wait);
 644         write_unlock_irqrestore(&waitqueue_lock, flags);
 645 }
 646
 647 extern inline void __remove_wait_queue(struct wait_queue ** p, struct wait_queue * wait)
 648 {
 649         struct wait_queue * next = wait->next;
 650         struct wait_queue * head = next;
 651         struct wait_queue * tmp;
 652
 653         while ((tmp = head->next) != wait) {
 654                 head = tmp;
 655         }
 656         head->next = next;
 657 }
 658
 659 extern inline void remove_wait_queue(struct wait_queue ** p, struct wait_queue * wait)
 660 {
 661         unsigned long flags;
 662
 663         write_lock_irqsave(&waitqueue_lock, flags);
 664         __remove_wait_queue(p, wait);
 665         write_unlock_irqrestore(&waitqueue_lock, flags);
 666 }
 667
 668 #define REMOVE_LINKS(p) do { \
 669         (p)->next_task->prev_task = (p)->prev_task; \
 670         (p)->prev_task->next_task = (p)->next_task; \
 671         if ((p)->p_osptr) \
 672                 (p)->p_osptr->p_ysptr = (p)->p_ysptr; \
 673         if ((p)->p_ysptr) \
 674                 (p)->p_ysptr->p_osptr = (p)->p_osptr; \
 675         else \
 676                 (p)->p_pptr->p_cptr = (p)->p_osptr; \
 677         } while (0)
 678
 679 #define SET_LINKS(p) do { \
 680         (p)->next_task = &init_task; \
 681         (p)->prev_task = init_task.prev_task; \
 682         init_task.prev_task->next_task = (p); \
 683         init_task.prev_task = (p); \
 684         (p)->p_ysptr = NULL; \
 685         if (((p)->p_osptr = (p)->p_pptr->p_cptr) != NULL) \
 686                 (p)->p_osptr->p_ysptr = p; \
 687         (p)->p_pptr->p_cptr = p; \
 688         } while (0)
 689
 690 #define for_each_task(p) \
 691         for (p = &init_task ; (p = p->next_task) != &init_task ; )
 692
 693 #endif /* __KERNEL__ */
 694
 695 #endif