kernel/fork.c

   1 /*
   2  *  linux/kernel/fork.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  */
   6
   7 /*
   8  *  'fork.c' contains the help-routines for the 'fork' system call
   9  * (see also entry.S and others).
  10  * Fork is rather simple, once you get the hang of it, but the memory
  11  * management can be a bitch. See 'mm/memory.c': 'copy_page_tables()'
  12  */
  13
  14 #include <linux/config.h>
  15 #include <linux/malloc.h>
  16 #include <linux/init.h>
  17 #include <linux/unistd.h>
  18 #include <linux/smp_lock.h>
  19 #include <linux/module.h>
  20 #include <linux/vmalloc.h>
  21
  22 #include <asm/pgtable.h>
  23 #include <asm/pgalloc.h>
  24 #include <asm/uaccess.h>
  25 #include <asm/mmu_context.h>
  26
  27 /* The idle threads do not count.. */
  28 int nr_threads;
  29 int nr_running;
  30
  31 int max_threads;
  32 unsigned long total_forks;      /* Handle normal Linux uptimes. */
  33 int last_pid;
  34
  35 struct task_struct *pidhash[PIDHASH_SZ];
  36
  37 void add_wait_queue(wait_queue_head_t *q, wait_queue_t * wait)
  38 {
  39         unsigned long flags;
  40
  41         wq_write_lock_irqsave(&q->lock, flags);
  42         wait->flags = 0;
  43         __add_wait_queue(q, wait);
  44         wq_write_unlock_irqrestore(&q->lock, flags);
  45 }
  46
  47 void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t * wait)
  48 {
  49         unsigned long flags;
  50
  51         wq_write_lock_irqsave(&q->lock, flags);
  52         wait->flags = WQ_FLAG_EXCLUSIVE;
  53         __add_wait_queue_tail(q, wait);
  54         wq_write_unlock_irqrestore(&q->lock, flags);
  55 }
  56
  57 void remove_wait_queue(wait_queue_head_t *q, wait_queue_t * wait)
  58 {
  59         unsigned long flags;
  60
  61         wq_write_lock_irqsave(&q->lock, flags);
  62         __remove_wait_queue(q, wait);
  63         wq_write_unlock_irqrestore(&q->lock, flags);
  64 }
  65
  66 void __init fork_init(unsigned long mempages)
  67 {
  68         /*
  69          * The default maximum number of threads is set to a safe
  70          * value: the thread structures can take up at most half
  71          * of memory.
  72          */
  73         max_threads = mempages / (THREAD_SIZE/PAGE_SIZE) / 2;
  74
  75         init_task.rlim[RLIMIT_NPROC].rlim_cur = max_threads/2;
  76         init_task.rlim[RLIMIT_NPROC].rlim_max = max_threads/2;
  77 }
  78
  79 /* Protects next_safe and last_pid. */
  80 spinlock_t lastpid_lock = SPIN_LOCK_UNLOCKED;
  81
  82 static int get_pid(unsigned long flags)
  83 {
  84         static int next_safe = PID_MAX;
  85         struct task_struct *p;
  86
  87         if (flags & CLONE_PID)
  88                 return current->pid;
  89
  90         spin_lock(&lastpid_lock);
  91         if((++last_pid) & 0xffff8000) {
  92                 last_pid = 300;         /* Skip daemons etc. */
  93                 goto inside;
  94         }
  95         if(last_pid >= next_safe) {
  96 inside:
  97                 next_safe = PID_MAX;
  98                 read_lock(&tasklist_lock);
  99         repeat:
 100                 for_each_task(p) {
 101                         if(p->pid == last_pid   ||
 102                            p->pgrp == last_pid  ||
 103                            p->session == last_pid) {
 104                                 if(++last_pid >= next_safe) {
 105                                         if(last_pid & 0xffff8000)
 106                                                 last_pid = 300;
 107                                         next_safe = PID_MAX;
 108                                 }
 109                                 goto repeat;
 110                         }
 111                         if(p->pid > last_pid && next_safe > p->pid)
 112                                 next_safe = p->pid;
 113                         if(p->pgrp > last_pid && next_safe > p->pgrp)
 114                                 next_safe = p->pgrp;
 115                         if(p->session > last_pid && next_safe > p->session)
 116                                 next_safe = p->session;
 117                 }
 118                 read_unlock(&tasklist_lock);
 119         }
 120         spin_unlock(&lastpid_lock);
 121
 122         return last_pid;
 123 }
 124
 125 static inline int dup_mmap(struct mm_struct * mm)
 126 {
 127         struct vm_area_struct * mpnt, *tmp, **pprev;
 128         int retval;
 129
 130         flush_cache_mm(current->mm);
 131         mm->locked_vm = 0;
 132         mm->mmap = NULL;
 133         mm->mmap_avl = NULL;
 134         mm->mmap_cache = NULL;
 135         mm->map_count = 0;
 136         mm->cpu_vm_mask = 0;
 137         mm->swap_cnt = 0;
 138         mm->swap_address = 0;
 139         pprev = &mm->mmap;
 140         for (mpnt = current->mm->mmap ; mpnt ; mpnt = mpnt->vm_next) {
 141                 struct file *file;
 142
 143                 retval = -ENOMEM;
 144                 if(mpnt->vm_flags & VM_DONTCOPY)
 145                         continue;
 146                 tmp = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
 147                 if (!tmp)
 148                         goto fail_nomem;
 149                 *tmp = *mpnt;
 150                 tmp->vm_flags &= ~VM_LOCKED;
 151                 tmp->vm_mm = mm;
 152                 mm->map_count++;
 153                 tmp->vm_next = NULL;
 154                 file = tmp->vm_file;
 155                 if (file) {
 156                         struct inode *inode = file->f_dentry->d_inode;
 157                         get_file(file);
 158                         if (tmp->vm_flags & VM_DENYWRITE)
 159                                 atomic_dec(&inode->i_writecount);
 160
 161                         /* insert tmp into the share list, just after mpnt */
 162                         spin_lock(&inode->i_mapping->i_shared_lock);
 163                         if((tmp->vm_next_share = mpnt->vm_next_share) != NULL)
 164                                 mpnt->vm_next_share->vm_pprev_share =
 165                                         &tmp->vm_next_share;
 166                         mpnt->vm_next_share = tmp;
 167                         tmp->vm_pprev_share = &mpnt->vm_next_share;
 168                         spin_unlock(&inode->i_mapping->i_shared_lock);
 169                 }
 170
 171                 /* Copy the pages, but defer checking for errors */
 172                 retval = copy_page_range(mm, current->mm, tmp);
 173                 if (!retval && tmp->vm_ops && tmp->vm_ops->open)
 174                         tmp->vm_ops->open(tmp);
 175
 176                 /*
 177                  * Link in the new vma even if an error occurred,
 178                  * so that exit_mmap() can clean up the mess.
 179                  */
 180                 *pprev = tmp;
 181                 pprev = &tmp->vm_next;
 182
 183                 if (retval)
 184                         goto fail_nomem;
 185         }
 186         retval = 0;
 187         if (mm->map_count >= AVL_MIN_MAP_COUNT)
 188                 build_mmap_avl(mm);
 189
 190 fail_nomem:
 191         flush_tlb_mm(current->mm);
 192         return retval;
 193 }
 194
 195 #define allocate_mm()   (kmem_cache_alloc(mm_cachep, SLAB_KERNEL))
 196 #define free_mm(mm)     (kmem_cache_free(mm_cachep, (mm)))
 197
 198 static struct mm_struct * mm_init(struct mm_struct * mm)
 199 {
 200         atomic_set(&mm->mm_users, 1);
 201         atomic_set(&mm->mm_count, 1);
 202         init_MUTEX(&mm->mmap_sem);
 203         mm->page_table_lock = SPIN_LOCK_UNLOCKED;
 204         mm->pgd = pgd_alloc();
 205         if (mm->pgd)
 206                 return mm;
 207         free_mm(mm);
 208         return NULL;
 209 }
 210
 211
 212 /*
 213  * Allocate and initialize an mm_struct.
 214  */
 215 struct mm_struct * mm_alloc(void)
 216 {
 217         struct mm_struct * mm;
 218
 219         mm = allocate_mm();
 220         if (mm) {
 221                 memset(mm, 0, sizeof(*mm));
 222                 return mm_init(mm);
 223         }
 224         return NULL;
 225 }
 226
 227 /*
 228  * Called when the last reference to the mm
 229  * is dropped: either by a lazy thread or by
 230  * mmput. Free the page directory and the mm.
 231  */
 232 inline void __mmdrop(struct mm_struct *mm)
 233 {
 234         if (mm == &init_mm) BUG();
 235         pgd_free(mm->pgd);
 236         destroy_context(mm);
 237         free_mm(mm);
 238 }
 239
 240 /*
 241  * Decrement the use count and release all resources for an mm.
 242  */
 243 void mmput(struct mm_struct *mm)
 244 {
 245         if (atomic_dec_and_test(&mm->mm_users)) {
 246                 exit_mmap(mm);
 247                 mmdrop(mm);
 248         }
 249 }
 250
 251 /* Please note the differences between mmput and mm_release.
 252  * mmput is called whenever we stop holding onto a mm_struct,
 253  * error success whatever.
 254  *
 255  * mm_release is called after a mm_struct has been removed
 256  * from the current process.
 257  *
 258  * This difference is important for error handling, when we
 259  * only half set up a mm_struct for a new process and need to restore
 260  * the old one.  Because we mmput the new mm_struct before
 261  * restoring the old one. . .
 262  * Eric Biederman 10 January 1998
 263  */
 264 void mm_release(void)
 265 {
 266         struct task_struct *tsk = current;
 267
 268         /* notify parent sleeping on vfork() */
 269         if (tsk->flags & PF_VFORK) {
 270                 tsk->flags &= ~PF_VFORK;
 271                 up(tsk->p_opptr->vfork_sem);
 272         }
 273 }
 274
 275 static inline int copy_mm(unsigned long clone_flags, struct task_struct * tsk)
 276 {
 277         struct mm_struct * mm;
 278         int retval;
 279
 280         tsk->min_flt = tsk->maj_flt = 0;
 281         tsk->cmin_flt = tsk->cmaj_flt = 0;
 282         tsk->nswap = tsk->cnswap = 0;
 283
 284         tsk->mm = NULL;
 285         tsk->active_mm = NULL;
 286
 287         /*
 288          * Are we cloning a kernel thread?
 289          *
 290          * We need to steal a active VM for that..
 291          */
 292         mm = current->mm;
 293         if (!mm)
 294                 return 0;
 295
 296         if (clone_flags & CLONE_VM) {
 297                 atomic_inc(&mm->mm_users);
 298                 goto good_mm;
 299         }
 300
 301         retval = -ENOMEM;
 302         mm = allocate_mm();
 303         if (!mm)
 304                 goto fail_nomem;
 305
 306         /* Copy the current MM stuff.. */
 307         memcpy(mm, current->mm, sizeof(*mm));
 308         if (!mm_init(mm))
 309                 goto fail_nomem;
 310
 311         tsk->mm = mm;
 312         tsk->active_mm = mm;
 313
 314         down(&current->mm->mmap_sem);
 315         retval = dup_mmap(mm);
 316         up(&current->mm->mmap_sem);
 317         if (retval)
 318                 goto free_pt;
 319
 320         /*
 321          * child gets a private LDT (if there was an LDT in the parent)
 322          */
 323         copy_segments(tsk, mm);
 324
 325         if (init_new_context(tsk,mm))
 326                 goto free_pt;
 327
 328 good_mm:
 329         tsk->mm = mm;
 330         tsk->active_mm = mm;
 331         return 0;
 332
 333 free_pt:
 334         mmput(mm);
 335 fail_nomem:
 336         return retval;
 337 }
 338
 339 static inline struct fs_struct *__copy_fs_struct(struct fs_struct *old)
 340 {
 341         struct fs_struct *fs = kmem_cache_alloc(fs_cachep, GFP_KERNEL);
 342         /* We don't need to lock fs - think why ;-) */
 343         if (fs) {
 344                 atomic_set(&fs->count, 1);
 345                 fs->lock = RW_LOCK_UNLOCKED;
 346                 fs->umask = old->umask;
 347                 read_lock(&old->lock);
 348                 fs->rootmnt = mntget(old->rootmnt);
 349                 fs->root = dget(old->root);
 350                 fs->pwdmnt = mntget(old->pwdmnt);
 351                 fs->pwd = dget(old->pwd);
 352                 if (old->altroot) {
 353                         fs->altrootmnt = mntget(old->altrootmnt);
 354                         fs->altroot = dget(old->altroot);
 355                 } else {
 356                         fs->altrootmnt = NULL;
 357                         fs->altroot = NULL;
 358                 }
 359                 read_unlock(&old->lock);
 360         }
 361         return fs;
 362 }
 363
 364 struct fs_struct *copy_fs_struct(struct fs_struct *old)
 365 {
 366         return __copy_fs_struct(old);
 367 }
 368
 369 static inline int copy_fs(unsigned long clone_flags, struct task_struct * tsk)
 370 {
 371         if (clone_flags & CLONE_FS) {
 372                 atomic_inc(&current->fs->count);
 373                 return 0;
 374         }
 375         tsk->fs = __copy_fs_struct(current->fs);
 376         if (!tsk->fs)
 377                 return -1;
 378         return 0;
 379 }
 380
 381 static int count_open_files(struct files_struct *files, int size)
 382 {
 383         int i;
 384
 385         /* Find the last open fd */
 386         for (i = size/(8*sizeof(long)); i > 0; ) {
 387                 if (files->open_fds->fds_bits[--i])
 388                         break;
 389         }
 390         i = (i+1) * 8 * sizeof(long);
 391         return i;
 392 }
 393
 394 static int copy_files(unsigned long clone_flags, struct task_struct * tsk)
 395 {
 396         struct files_struct *oldf, *newf;
 397         struct file **old_fds, **new_fds;
 398         int open_files, nfds, size, i, error = 0;
 399
 400         /*
 401          * A background process may not have any files ...
 402          */
 403         oldf = current->files;
 404         if (!oldf)
 405                 goto out;
 406
 407         if (clone_flags & CLONE_FILES) {
 408                 atomic_inc(&oldf->count);
 409                 goto out;
 410         }
 411
 412         tsk->files = NULL;
 413         error = -ENOMEM;
 414         newf = kmem_cache_alloc(files_cachep, SLAB_KERNEL);
 415         if (!newf)
 416                 goto out;
 417
 418         atomic_set(&newf->count, 1);
 419
 420         newf->file_lock     = RW_LOCK_UNLOCKED;
 421         newf->next_fd       = 0;
 422         newf->max_fds       = NR_OPEN_DEFAULT;
 423         newf->max_fdset     = __FD_SETSIZE;
 424         newf->close_on_exec = &newf->close_on_exec_init;
 425         newf->open_fds      = &newf->open_fds_init;
 426         newf->fd            = &newf->fd_array[0];
 427
 428         /* We don't yet have the oldf readlock, but even if the old
 429            fdset gets grown now, we'll only copy up to "size" fds */
 430         size = oldf->max_fdset;
 431         if (size > __FD_SETSIZE) {
 432                 newf->max_fdset = 0;
 433                 write_lock(&newf->file_lock);
 434                 error = expand_fdset(newf, size);
 435                 write_unlock(&newf->file_lock);
 436                 if (error)
 437                         goto out_release;
 438         }
 439         read_lock(&oldf->file_lock);
 440
 441         open_files = count_open_files(oldf, size);
 442
 443         /*
 444          * Check whether we need to allocate a larger fd array.
 445          * Note: we're not a clone task, so the open count won't
 446          * change.
 447          */
 448         nfds = NR_OPEN_DEFAULT;
 449         if (open_files > nfds) {
 450                 read_unlock(&oldf->file_lock);
 451                 newf->max_fds = 0;
 452                 write_lock(&newf->file_lock);
 453                 error = expand_fd_array(newf, open_files);
 454                 write_unlock(&newf->file_lock);
 455                 if (error)
 456                         goto out_release;
 457                 nfds = newf->max_fds;
 458                 read_lock(&oldf->file_lock);
 459         }
 460
 461         old_fds = oldf->fd;
 462         new_fds = newf->fd;
 463
 464         memcpy(newf->open_fds->fds_bits, oldf->open_fds->fds_bits, open_files/8);
 465         memcpy(newf->close_on_exec->fds_bits, oldf->close_on_exec->fds_bits, open_files/8);
 466
 467         for (i = open_files; i != 0; i--) {
 468                 struct file *f = *old_fds++;
 469                 if (f)
 470                         get_file(f);
 471                 *new_fds++ = f;
 472         }
 473         read_unlock(&oldf->file_lock);
 474
 475         /* compute the remainder to be cleared */
 476         size = (newf->max_fds - open_files) * sizeof(struct file *);
 477
 478         /* This is long word aligned thus could use a optimized version */
 479         memset(new_fds, 0, size);
 480
 481         if (newf->max_fdset > open_files) {
 482                 int left = (newf->max_fdset-open_files)/8;
 483                 int start = open_files / (8 * sizeof(unsigned long));
 484
 485                 memset(&newf->open_fds->fds_bits[start], 0, left);
 486                 memset(&newf->close_on_exec->fds_bits[start], 0, left);
 487         }
 488
 489         tsk->files = newf;
 490         error = 0;
 491 out:
 492         return error;
 493
 494 out_release:
 495         free_fdset (newf->close_on_exec, newf->max_fdset);
 496         free_fdset (newf->open_fds, newf->max_fdset);
 497         kmem_cache_free(files_cachep, newf);
 498         goto out;
 499 }
 500
 501 static inline int copy_sighand(unsigned long clone_flags, struct task_struct * tsk)
 502 {
 503         struct signal_struct *sig;
 504
 505         if (clone_flags & CLONE_SIGHAND) {
 506                 atomic_inc(&current->sig->count);
 507                 return 0;
 508         }
 509         sig = kmem_cache_alloc(sigact_cachep, GFP_KERNEL);
 510         tsk->sig = sig;
 511         if (!sig)
 512                 return -1;
 513         spin_lock_init(&sig->siglock);
 514         atomic_set(&sig->count, 1);
 515         memcpy(tsk->sig->action, current->sig->action, sizeof(tsk->sig->action));
 516         return 0;
 517 }
 518
 519 static inline void copy_flags(unsigned long clone_flags, struct task_struct *p)
 520 {
 521         unsigned long new_flags = p->flags;
 522
 523         new_flags &= ~(PF_SUPERPRIV | PF_USEDFPU | PF_VFORK);
 524         new_flags |= PF_FORKNOEXEC;
 525         if (!(clone_flags & CLONE_PTRACE))
 526                 p->ptrace = 0;
 527         if (clone_flags & CLONE_VFORK)
 528                 new_flags |= PF_VFORK;
 529         p->flags = new_flags;
 530 }
 531
 532 /*
 533  *  Ok, this is the main fork-routine. It copies the system process
 534  * information (task[nr]) and sets up the necessary registers. It also
 535  * copies the data segment in its entirety.  The "stack_start" and
 536  * "stack_top" arguments are simply passed along to the platform
 537  * specific copy_thread() routine.  Most platforms ignore stack_top.
 538  * For an example that's using stack_top, see
 539  * arch/ia64/kernel/process.c.
 540  */
 541 int do_fork(unsigned long clone_flags, unsigned long stack_start,
 542             struct pt_regs *regs, unsigned long stack_size)
 543 {
 544         int retval = -ENOMEM;
 545         struct task_struct *p;
 546         DECLARE_MUTEX_LOCKED(sem);
 547
 548         if (clone_flags & CLONE_PID) {
 549                 /* This is only allowed from the boot up thread */
 550                 if (current->pid)
 551                         return -EPERM;
 552         }
 553
 554         current->vfork_sem = &sem;
 555
 556         p = alloc_task_struct();
 557         if (!p)
 558                 goto fork_out;
 559
 560         *p = *current;
 561
 562         retval = -EAGAIN;
 563         if (atomic_read(&p->user->processes) >= p->rlim[RLIMIT_NPROC].rlim_cur)
 564                 goto bad_fork_free;
 565         atomic_inc(&p->user->__count);
 566         atomic_inc(&p->user->processes);
 567
 568         /*
 569          * Counter increases are protected by
 570          * the kernel lock so nr_threads can't
 571          * increase under us (but it may decrease).
 572          */
 573         if (nr_threads >= max_threads)
 574                 goto bad_fork_cleanup_count;
 575
 576         get_exec_domain(p->exec_domain);
 577
 578         if (p->binfmt && p->binfmt->module)
 579                 __MOD_INC_USE_COUNT(p->binfmt->module);
 580
 581         p->did_exec = 0;
 582         p->swappable = 0;
 583         p->state = TASK_UNINTERRUPTIBLE;
 584
 585         copy_flags(clone_flags, p);
 586         p->pid = get_pid(clone_flags);
 587
 588         p->run_list.next = NULL;
 589         p->run_list.prev = NULL;
 590
 591         if ((clone_flags & CLONE_VFORK) || !(clone_flags & CLONE_PARENT)) {
 592                 p->p_opptr = current;
 593                 if (!(p->ptrace & PT_PTRACED))
 594                         p->p_pptr = current;
 595         }
 596         p->p_cptr = NULL;
 597         init_waitqueue_head(&p->wait_chldexit);
 598         p->vfork_sem = NULL;
 599         spin_lock_init(&p->alloc_lock);
 600
 601         p->sigpending = 0;
 602         init_sigpending(&p->pending);
 603
 604         p->it_real_value = p->it_virt_value = p->it_prof_value = 0;
 605         p->it_real_incr = p->it_virt_incr = p->it_prof_incr = 0;
 606         init_timer(&p->real_timer);
 607         p->real_timer.data = (unsigned long) p;
 608
 609         p->leader = 0;          /* session leadership doesn't inherit */
 610         p->tty_old_pgrp = 0;
 611         p->times.tms_utime = p->times.tms_stime = 0;
 612         p->times.tms_cutime = p->times.tms_cstime = 0;
 613 #ifdef CONFIG_SMP
 614         {
 615                 int i;
 616                 p->has_cpu = 0;
 617                 p->processor = current->processor;
 618                 /* ?? should we just memset this ?? */
 619                 for(i = 0; i < smp_num_cpus; i++)
 620                         p->per_cpu_utime[i] = p->per_cpu_stime[i] = 0;
 621                 spin_lock_init(&p->sigmask_lock);
 622         }
 623 #endif
 624         p->lock_depth = -1;             /* -1 = no lock */
 625         p->start_time = jiffies;
 626
 627         retval = -ENOMEM;
 628         /* copy all the process information */
 629         if (copy_files(clone_flags, p))
 630                 goto bad_fork_cleanup;
 631         if (copy_fs(clone_flags, p))
 632                 goto bad_fork_cleanup_files;
 633         if (copy_sighand(clone_flags, p))
 634                 goto bad_fork_cleanup_fs;
 635         if (copy_mm(clone_flags, p))
 636                 goto bad_fork_cleanup_sighand;
 637         retval = copy_thread(0, clone_flags, stack_start, stack_size, p, regs);
 638         if (retval)
 639                 goto bad_fork_cleanup_sighand;
 640         p->semundo = NULL;
 641
 642         /* Our parent execution domain becomes current domain
 643            These must match for thread signalling to apply */
 644
 645         p->parent_exec_id = p->self_exec_id;
 646
 647         /* ok, now we should be set up.. */
 648         p->swappable = 1;
 649         p->exit_signal = clone_flags & CSIGNAL;
 650         p->pdeath_signal = 0;
 651
 652         /*
 653          * "share" dynamic priority between parent and child, thus the
 654          * total amount of dynamic priorities in the system doesnt change,
 655          * more scheduling fairness. This is only important in the first
 656          * timeslice, on the long run the scheduling behaviour is unchanged.
 657          */
 658         p->counter = (current->counter + 1) >> 1;
 659         current->counter >>= 1;
 660         if (!current->counter)
 661                 current->need_resched = 1;
 662
 663         /*
 664          * Ok, add it to the run-queues and make it
 665          * visible to the rest of the system.
 666          *
 667          * Let it rip!
 668          */
 669         retval = p->pid;
 670         p->tgid = retval;
 671         INIT_LIST_HEAD(&p->thread_group);
 672         write_lock_irq(&tasklist_lock);
 673         if (clone_flags & CLONE_THREAD) {
 674                 p->tgid = current->tgid;
 675                 list_add(&p->thread_group, &current->thread_group);
 676         }
 677         SET_LINKS(p);
 678         hash_pid(p);
 679         nr_threads++;
 680         write_unlock_irq(&tasklist_lock);
 681
 682         if (p->ptrace & PT_PTRACED)
 683                 send_sig(SIGSTOP, p, 1);
 684
 685         wake_up_process(p);             /* do this last */
 686         ++total_forks;
 687
 688 fork_out:
 689         if ((clone_flags & CLONE_VFORK) && (retval > 0))
 690                 down(&sem);
 691         return retval;
 692
 693 bad_fork_cleanup_sighand:
 694         exit_sighand(p);
 695 bad_fork_cleanup_fs:
 696         exit_fs(p); /* blocking */
 697 bad_fork_cleanup_files:
 698         exit_files(p); /* blocking */
 699 bad_fork_cleanup:
 700         put_exec_domain(p->exec_domain);
 701         if (p->binfmt && p->binfmt->module)
 702                 __MOD_DEC_USE_COUNT(p->binfmt->module);
 703 bad_fork_cleanup_count:
 704         atomic_dec(&p->user->processes);
 705         free_uid(p->user);
 706 bad_fork_free:
 707         free_task_struct(p);
 708         goto fork_out;
 709 }
 710
 711 /* SLAB cache for signal_struct structures (tsk->sig) */
 712 kmem_cache_t *sigact_cachep;
 713
 714 /* SLAB cache for files_struct structures (tsk->files) */
 715 kmem_cache_t *files_cachep;
 716
 717 /* SLAB cache for fs_struct structures (tsk->fs) */
 718 kmem_cache_t *fs_cachep;
 719
 720 /* SLAB cache for vm_area_struct structures */
 721 kmem_cache_t *vm_area_cachep;
 722
 723 /* SLAB cache for mm_struct structures (tsk->mm) */
 724 kmem_cache_t *mm_cachep;
 725
 726 void __init proc_caches_init(void)
 727 {
 728         sigact_cachep = kmem_cache_create("signal_act",
 729                         sizeof(struct signal_struct), 0,
 730                         SLAB_HWCACHE_ALIGN, NULL, NULL);
 731         if (!sigact_cachep)
 732                 panic("Cannot create signal action SLAB cache");
 733
 734         files_cachep = kmem_cache_create("files_cache",
 735                          sizeof(struct files_struct), 0,
 736                          SLAB_HWCACHE_ALIGN, NULL, NULL);
 737         if (!files_cachep)
 738                 panic("Cannot create files SLAB cache");
 739
 740         fs_cachep = kmem_cache_create("fs_cache",
 741                          sizeof(struct fs_struct), 0,
 742                          SLAB_HWCACHE_ALIGN, NULL, NULL);
 743         if (!fs_cachep)
 744                 panic("Cannot create fs_struct SLAB cache");
 745
 746         vm_area_cachep = kmem_cache_create("vm_area_struct",
 747                         sizeof(struct vm_area_struct), 0,
 748                         SLAB_HWCACHE_ALIGN, NULL, NULL);
 749         if(!vm_area_cachep)
 750                 panic("vma_init: Cannot alloc vm_area_struct SLAB cache");
 751
 752         mm_cachep = kmem_cache_create("mm_struct",
 753                         sizeof(struct mm_struct), 0,
 754                         SLAB_HWCACHE_ALIGN, NULL, NULL);
 755         if(!mm_cachep)
 756                 panic("vma_init: Cannot alloc mm_struct SLAB cache");
 757 }