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_range()'
  12  */
  13
  14 #include <linux/config.h>
  15 #include <linux/slab.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 #include <linux/completion.h>
  22 #include <linux/namespace.h>
  23 #include <linux/personality.h>
  24 #include <linux/mempolicy.h>
  25 #include <linux/sem.h>
  26 #include <linux/file.h>
  27 #include <linux/binfmts.h>
  28 #include <linux/mman.h>
  29 #include <linux/fs.h>
  30 #include <linux/cpu.h>
  31 #include <linux/security.h>
  32 #include <linux/syscalls.h>
  33 #include <linux/jiffies.h>
  34 #include <linux/futex.h>
  35 #include <linux/ptrace.h>
  36 #include <linux/mount.h>
  37 #include <linux/audit.h>
  38 #include <linux/rmap.h>
  39 #include <linux/vinline.h>
  40 #include <linux/ninline.h>
  41
  42 #include <asm/pgtable.h>
  43 #include <asm/pgalloc.h>
  44 #include <asm/uaccess.h>
  45 #include <asm/mmu_context.h>
  46 #include <asm/cacheflush.h>
  47 #include <asm/tlbflush.h>
  48
  49 /* The idle threads do not count..
  50  * Protected by write_lock_irq(&tasklist_lock)
  51  */
  52 int nr_threads;
  53
  54 int max_threads;
  55 unsigned long total_forks;      /* Handle normal Linux uptimes. */
  56
  57 DEFINE_PER_CPU(unsigned long, process_counts) = 0;
  58
  59 rwlock_t tasklist_lock __cacheline_aligned = RW_LOCK_UNLOCKED;  /* outer */
  60
  61 EXPORT_SYMBOL(tasklist_lock);
  62
  63 int nr_processes(void)
  64 {
  65         int cpu;
  66         int total = 0;
  67
  68         for_each_online_cpu(cpu)
  69                 total += per_cpu(process_counts, cpu);
  70
  71         return total;
  72 }
  73
  74 #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR
  75 # define alloc_task_struct()    kmem_cache_alloc(task_struct_cachep, GFP_KERNEL)
  76 # define free_task_struct(tsk)  kmem_cache_free(task_struct_cachep, (tsk))
  77 static kmem_cache_t *task_struct_cachep;
  78 #endif
  79
  80 static void free_task(struct task_struct *tsk)
  81 {
  82         free_thread_info(tsk->thread_info);
  83         vxdprintk("freeing up task %p\n", tsk);
  84         clr_vx_info(&tsk->vx_info);
  85         clr_nx_info(&tsk->nx_info);
  86         free_task_struct(tsk);
  87 }
  88
  89 void __put_task_struct(struct task_struct *tsk)
  90 {
  91         WARN_ON(!(tsk->state & (TASK_DEAD | TASK_ZOMBIE)));
  92         WARN_ON(atomic_read(&tsk->usage));
  93         WARN_ON(tsk == current);
  94
  95         if (unlikely(tsk->audit_context))
  96                 audit_free(tsk);
  97         security_task_free(tsk);
  98         free_uid(tsk->user);
  99         put_group_info(tsk->group_info);
 100         free_task(tsk);
 101 }
 102
 103 void fastcall add_wait_queue(wait_queue_head_t *q, wait_queue_t * wait)
 104 {
 105         unsigned long flags;
 106
 107         wait->flags &= ~WQ_FLAG_EXCLUSIVE;
 108         spin_lock_irqsave(&q->lock, flags);
 109         __add_wait_queue(q, wait);
 110         spin_unlock_irqrestore(&q->lock, flags);
 111 }
 112
 113 EXPORT_SYMBOL(add_wait_queue);
 114
 115 void fastcall add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t * wait)
 116 {
 117         unsigned long flags;
 118
 119         wait->flags |= WQ_FLAG_EXCLUSIVE;
 120         spin_lock_irqsave(&q->lock, flags);
 121         __add_wait_queue_tail(q, wait);
 122         spin_unlock_irqrestore(&q->lock, flags);
 123 }
 124
 125 EXPORT_SYMBOL(add_wait_queue_exclusive);
 126
 127 void fastcall remove_wait_queue(wait_queue_head_t *q, wait_queue_t * wait)
 128 {
 129         unsigned long flags;
 130
 131         spin_lock_irqsave(&q->lock, flags);
 132         __remove_wait_queue(q, wait);
 133         spin_unlock_irqrestore(&q->lock, flags);
 134 }
 135
 136 EXPORT_SYMBOL(remove_wait_queue);
 137
 138
 139 /*
 140  * Note: we use "set_current_state()" _after_ the wait-queue add,
 141  * because we need a memory barrier there on SMP, so that any
 142  * wake-function that tests for the wait-queue being active
 143  * will be guaranteed to see waitqueue addition _or_ subsequent
 144  * tests in this thread will see the wakeup having taken place.
 145  *
 146  * The spin_unlock() itself is semi-permeable and only protects
 147  * one way (it only protects stuff inside the critical region and
 148  * stops them from bleeding out - it would still allow subsequent
 149  * loads to move into the the critical region).
 150  */
 151 void fastcall prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, int state)
 152 {
 153         unsigned long flags;
 154
 155         wait->flags &= ~WQ_FLAG_EXCLUSIVE;
 156         spin_lock_irqsave(&q->lock, flags);
 157         if (list_empty(&wait->task_list))
 158                 __add_wait_queue(q, wait);
 159         set_current_state(state);
 160         spin_unlock_irqrestore(&q->lock, flags);
 161 }
 162
 163 EXPORT_SYMBOL(prepare_to_wait);
 164
 165 void fastcall
 166 prepare_to_wait_exclusive(wait_queue_head_t *q, wait_queue_t *wait, int state)
 167 {
 168         unsigned long flags;
 169
 170         wait->flags |= WQ_FLAG_EXCLUSIVE;
 171         spin_lock_irqsave(&q->lock, flags);
 172         if (list_empty(&wait->task_list))
 173                 __add_wait_queue_tail(q, wait);
 174         set_current_state(state);
 175         spin_unlock_irqrestore(&q->lock, flags);
 176 }
 177
 178 EXPORT_SYMBOL(prepare_to_wait_exclusive);
 179
 180 void fastcall finish_wait(wait_queue_head_t *q, wait_queue_t *wait)
 181 {
 182         unsigned long flags;
 183
 184         __set_current_state(TASK_RUNNING);
 185         /*
 186          * We can check for list emptiness outside the lock
 187          * IFF:
 188          *  - we use the "careful" check that verifies both
 189          *    the next and prev pointers, so that there cannot
 190          *    be any half-pending updates in progress on other
 191          *    CPU's that we haven't seen yet (and that might
 192          *    still change the stack area.
 193          * and
 194          *  - all other users take the lock (ie we can only
 195          *    have _one_ other CPU that looks at or modifies
 196          *    the list).
 197          */
 198         if (!list_empty_careful(&wait->task_list)) {
 199                 spin_lock_irqsave(&q->lock, flags);
 200                 list_del_init(&wait->task_list);
 201                 spin_unlock_irqrestore(&q->lock, flags);
 202         }
 203 }
 204
 205 EXPORT_SYMBOL(finish_wait);
 206
 207 int autoremove_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key)
 208 {
 209         int ret = default_wake_function(wait, mode, sync, key);
 210
 211         if (ret)
 212                 list_del_init(&wait->task_list);
 213         return ret;
 214 }
 215
 216 EXPORT_SYMBOL(autoremove_wake_function);
 217
 218 void __init fork_init(unsigned long mempages)
 219 {
 220 #ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR
 221 #ifndef ARCH_MIN_TASKALIGN
 222 #define ARCH_MIN_TASKALIGN      L1_CACHE_BYTES
 223 #endif
 224         /* create a slab on which task_structs can be allocated */
 225         task_struct_cachep =
 226                 kmem_cache_create("task_struct", sizeof(struct task_struct),
 227                         ARCH_MIN_TASKALIGN, SLAB_PANIC, NULL, NULL);
 228 #endif
 229
 230         /*
 231          * The default maximum number of threads is set to a safe
 232          * value: the thread structures can take up at most half
 233          * of memory.
 234          */
 235         max_threads = mempages / (THREAD_SIZE/PAGE_SIZE) / 8;
 236         /*
 237          * we need to allow at least 20 threads to boot a system
 238          */
 239         if(max_threads < 20)
 240                 max_threads = 20;
 241
 242         init_task.rlim[RLIMIT_NPROC].rlim_cur = max_threads/2;
 243         init_task.rlim[RLIMIT_NPROC].rlim_max = max_threads/2;
 244 }
 245
 246 static struct task_struct *dup_task_struct(struct task_struct *orig)
 247 {
 248         struct task_struct *tsk;
 249         struct thread_info *ti;
 250
 251         prepare_to_copy(orig);
 252
 253         tsk = alloc_task_struct();
 254         if (!tsk)
 255                 return NULL;
 256
 257         ti = alloc_thread_info(tsk);
 258         if (!ti) {
 259                 free_task_struct(tsk);
 260                 return NULL;
 261         }
 262
 263         *ti = *orig->thread_info;
 264         *tsk = *orig;
 265         tsk->thread_info = ti;
 266         ti->task = tsk;
 267
 268         /* One for us, one for whoever does the "release_task()" (usually parent) */
 269         atomic_set(&tsk->usage,2);
 270         return tsk;
 271 }
 272
 273 #ifdef CONFIG_MMU
 274 static inline int dup_mmap(struct mm_struct * mm, struct mm_struct * oldmm)
 275 {
 276         struct vm_area_struct * mpnt, *tmp, **pprev;
 277         struct rb_node **rb_link, *rb_parent;
 278         int retval;
 279         unsigned long charge = 0;
 280         struct mempolicy *pol;
 281
 282         down_write(&oldmm->mmap_sem);
 283         flush_cache_mm(current->mm);
 284         mm->locked_vm = 0;
 285         mm->mmap = NULL;
 286         mm->mmap_cache = NULL;
 287         mm->free_area_cache = TASK_UNMAPPED_BASE;
 288         mm->map_count = 0;
 289         mm->rss = 0;
 290         cpus_clear(mm->cpu_vm_mask);
 291         mm->mm_rb = RB_ROOT;
 292         rb_link = &mm->mm_rb.rb_node;
 293         rb_parent = NULL;
 294         pprev = &mm->mmap;
 295
 296         /*
 297          * Add it to the mmlist after the parent.
 298          * Doing it this way means that we can order the list,
 299          * and fork() won't mess up the ordering significantly.
 300          * Add it first so that swapoff can see any swap entries.
 301          */
 302         spin_lock(&mmlist_lock);
 303         list_add(&mm->mmlist, &current->mm->mmlist);
 304         mmlist_nr++;
 305         spin_unlock(&mmlist_lock);
 306
 307         for (mpnt = current->mm->mmap ; mpnt ; mpnt = mpnt->vm_next) {
 308                 struct file *file;
 309
 310                 if(mpnt->vm_flags & VM_DONTCOPY)
 311                         continue;
 312                 if (mpnt->vm_flags & VM_ACCOUNT) {
 313                         unsigned int len = (mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT;
 314                         if (security_vm_enough_memory(len))
 315                                 goto fail_nomem;
 316                         charge += len;
 317                 }
 318                 tmp = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
 319                 if (!tmp)
 320                         goto fail_nomem;
 321                 *tmp = *mpnt;
 322                 pol = mpol_copy(vma_policy(mpnt));
 323                 retval = PTR_ERR(pol);
 324                 if (IS_ERR(pol))
 325                         goto fail_nomem_policy;
 326                 vma_set_policy(tmp, pol);
 327                 tmp->vm_flags &= ~VM_LOCKED;
 328                 tmp->vm_mm = mm;
 329                 tmp->vm_next = NULL;
 330                 anon_vma_link(tmp);
 331                 vma_prio_tree_init(tmp);
 332                 file = tmp->vm_file;
 333                 if (file) {
 334                         struct inode *inode = file->f_dentry->d_inode;
 335                         get_file(file);
 336                         if (tmp->vm_flags & VM_DENYWRITE)
 337                                 atomic_dec(&inode->i_writecount);
 338
 339                         /* insert tmp into the share list, just after mpnt */
 340                         spin_lock(&file->f_mapping->i_mmap_lock);
 341                         flush_dcache_mmap_lock(file->f_mapping);
 342                         vma_prio_tree_add(tmp, mpnt);
 343                         flush_dcache_mmap_unlock(file->f_mapping);
 344                         spin_unlock(&file->f_mapping->i_mmap_lock);
 345                 }
 346
 347                 /*
 348                  * Link in the new vma and copy the page table entries:
 349                  * link in first so that swapoff can see swap entries,
 350                  * and try_to_unmap_one's find_vma find the new vma.
 351                  */
 352                 spin_lock(&mm->page_table_lock);
 353                 *pprev = tmp;
 354                 pprev = &tmp->vm_next;
 355
 356                 __vma_link_rb(mm, tmp, rb_link, rb_parent);
 357                 rb_link = &tmp->vm_rb.rb_right;
 358                 rb_parent = &tmp->vm_rb;
 359
 360                 mm->map_count++;
 361                 retval = copy_page_range(mm, current->mm, tmp);
 362                 spin_unlock(&mm->page_table_lock);
 363
 364                 if (tmp->vm_ops && tmp->vm_ops->open)
 365                         tmp->vm_ops->open(tmp);
 366
 367                 if (retval)
 368                         goto fail;
 369         }
 370         retval = 0;
 371
 372 out:
 373         flush_tlb_mm(current->mm);
 374         up_write(&oldmm->mmap_sem);
 375         return retval;
 376 fail_nomem_policy:
 377         kmem_cache_free(vm_area_cachep, tmp);
 378 fail_nomem:
 379         retval = -ENOMEM;
 380 fail:
 381         vm_unacct_memory(charge);
 382         goto out;
 383 }
 384 static inline int mm_alloc_pgd(struct mm_struct * mm)
 385 {
 386         mm->pgd = pgd_alloc(mm);
 387         if (unlikely(!mm->pgd))
 388                 return -ENOMEM;
 389         return 0;
 390 }
 391
 392 static inline void mm_free_pgd(struct mm_struct * mm)
 393 {
 394         pgd_free(mm->pgd);
 395 }
 396 #else
 397 #define dup_mmap(mm, oldmm)     (0)
 398 #define mm_alloc_pgd(mm)        (0)
 399 #define mm_free_pgd(mm)
 400 #endif /* CONFIG_MMU */
 401
 402 spinlock_t mmlist_lock __cacheline_aligned_in_smp = SPIN_LOCK_UNLOCKED;
 403 int mmlist_nr;
 404
 405 #define allocate_mm()   (kmem_cache_alloc(mm_cachep, SLAB_KERNEL))
 406 #define free_mm(mm)     (kmem_cache_free(mm_cachep, (mm)))
 407
 408 #include <linux/init_task.h>
 409
 410 static struct mm_struct * mm_init(struct mm_struct * mm)
 411 {
 412         atomic_set(&mm->mm_users, 1);
 413         atomic_set(&mm->mm_count, 1);
 414         init_rwsem(&mm->mmap_sem);
 415         mm->core_waiters = 0;
 416         mm->page_table_lock = SPIN_LOCK_UNLOCKED;
 417         mm->ioctx_list_lock = RW_LOCK_UNLOCKED;
 418         mm->ioctx_list = NULL;
 419         mm->default_kioctx = (struct kioctx)INIT_KIOCTX(mm->default_kioctx, *mm);
 420         mm->free_area_cache = TASK_UNMAPPED_BASE;
 421
 422         if (likely(!mm_alloc_pgd(mm))) {
 423                 mm->def_flags = 0;
 424 #ifdef __HAVE_ARCH_MMAP_TOP
 425                 mm->mmap_top = mmap_top();
 426 #endif
 427                 set_vx_info(&mm->mm_vx_info, current->vx_info);
 428                 return mm;
 429         }
 430         free_mm(mm);
 431         return NULL;
 432 }
 433
 434 /*
 435  * Allocate and initialize an mm_struct.
 436  */
 437 struct mm_struct * mm_alloc(void)
 438 {
 439         struct mm_struct * mm;
 440
 441         mm = allocate_mm();
 442         if (mm) {
 443                 memset(mm, 0, sizeof(*mm));
 444                 mm = mm_init(mm);
 445         }
 446         return mm;
 447 }
 448
 449 /*
 450  * Called when the last reference to the mm
 451  * is dropped: either by a lazy thread or by
 452  * mmput. Free the page directory and the mm.
 453  */
 454 void fastcall __mmdrop(struct mm_struct *mm)
 455 {
 456         BUG_ON(mm == &init_mm);
 457         mm_free_pgd(mm);
 458         destroy_context(mm);
 459         clr_vx_info(&mm->mm_vx_info);
 460         free_mm(mm);
 461 }
 462
 463 /*
 464  * Decrement the use count and release all resources for an mm.
 465  */
 466 void mmput(struct mm_struct *mm)
 467 {
 468         if (atomic_dec_and_lock(&mm->mm_users, &mmlist_lock)) {
 469                 list_del(&mm->mmlist);
 470                 mmlist_nr--;
 471                 spin_unlock(&mmlist_lock);
 472                 exit_aio(mm);
 473                 exit_mmap(mm);
 474                 mmdrop(mm);
 475         }
 476 }
 477
 478 /*
 479  * Checks if the use count of an mm is non-zero and if so
 480  * returns a reference to it after bumping up the use count.
 481  * If the use count is zero, it means this mm is going away,
 482  * so return NULL.
 483  */
 484 struct mm_struct *mmgrab(struct mm_struct *mm)
 485 {
 486         spin_lock(&mmlist_lock);
 487         if (!atomic_read(&mm->mm_users))
 488                 mm = NULL;
 489         else
 490                 atomic_inc(&mm->mm_users);
 491         spin_unlock(&mmlist_lock);
 492         return mm;
 493 }
 494
 495 /* Please note the differences between mmput and mm_release.
 496  * mmput is called whenever we stop holding onto a mm_struct,
 497  * error success whatever.
 498  *
 499  * mm_release is called after a mm_struct has been removed
 500  * from the current process.
 501  *
 502  * This difference is important for error handling, when we
 503  * only half set up a mm_struct for a new process and need to restore
 504  * the old one.  Because we mmput the new mm_struct before
 505  * restoring the old one. . .
 506  * Eric Biederman 10 January 1998
 507  */
 508 void mm_release(struct task_struct *tsk, struct mm_struct *mm)
 509 {
 510         struct completion *vfork_done = tsk->vfork_done;
 511
 512         /* Get rid of any cached register state */
 513         deactivate_mm(tsk, mm);
 514
 515         /* notify parent sleeping on vfork() */
 516         if (vfork_done) {
 517                 tsk->vfork_done = NULL;
 518                 complete(vfork_done);
 519         }
 520         if (tsk->clear_child_tid && atomic_read(&mm->mm_users) > 1) {
 521                 u32 __user * tidptr = tsk->clear_child_tid;
 522                 tsk->clear_child_tid = NULL;
 523
 524                 /*
 525                  * We don't check the error code - if userspace has
 526                  * not set up a proper pointer then tough luck.
 527                  */
 528                 put_user(0, tidptr);
 529                 sys_futex(tidptr, FUTEX_WAKE, 1, NULL, NULL);
 530         }
 531 }
 532
 533 static int copy_mm(unsigned long clone_flags, struct task_struct * tsk)
 534 {
 535         struct mm_struct * mm, *oldmm;
 536         int retval;
 537
 538         tsk->min_flt = tsk->maj_flt = 0;
 539         tsk->cmin_flt = tsk->cmaj_flt = 0;
 540         tsk->nvcsw = tsk->nivcsw = tsk->cnvcsw = tsk->cnivcsw = 0;
 541
 542         tsk->mm = NULL;
 543         tsk->active_mm = NULL;
 544
 545         /*
 546          * Are we cloning a kernel thread?
 547          *
 548          * We need to steal a active VM for that..
 549          */
 550         oldmm = current->mm;
 551         if (!oldmm)
 552                 return 0;
 553
 554         if (clone_flags & CLONE_VM) {
 555                 atomic_inc(&oldmm->mm_users);
 556                 mm = oldmm;
 557                 /*
 558                  * There are cases where the PTL is held to ensure no
 559                  * new threads start up in user mode using an mm, which
 560                  * allows optimizing out ipis; the tlb_gather_mmu code
 561                  * is an example.
 562                  */
 563                 spin_unlock_wait(&oldmm->page_table_lock);
 564                 goto good_mm;
 565         }
 566
 567         retval = -ENOMEM;
 568         mm = allocate_mm();
 569         if (!mm)
 570                 goto fail_nomem;
 571
 572         /* Copy the current MM stuff.. */
 573         memcpy(mm, oldmm, sizeof(*mm));
 574         mm->mm_vx_info = NULL;
 575         if (!mm_init(mm))
 576                 goto fail_nomem;
 577
 578         if (init_new_context(tsk,mm))
 579                 goto fail_nocontext;
 580
 581         retval = dup_mmap(mm, oldmm);
 582         if (retval)
 583                 goto free_pt;
 584
 585 good_mm:
 586         tsk->mm = mm;
 587         tsk->active_mm = mm;
 588         return 0;
 589
 590 free_pt:
 591         mmput(mm);
 592 fail_nomem:
 593         return retval;
 594
 595 fail_nocontext:
 596         /*
 597          * If init_new_context() failed, we cannot use mmput() to free the mm
 598          * because it calls destroy_context()
 599          */
 600         mm_free_pgd(mm);
 601         free_mm(mm);
 602         return retval;
 603 }
 604
 605 static inline struct fs_struct *__copy_fs_struct(struct fs_struct *old)
 606 {
 607         struct fs_struct *fs = kmem_cache_alloc(fs_cachep, GFP_KERNEL);
 608         /* We don't need to lock fs - think why ;-) */
 609         if (fs) {
 610                 atomic_set(&fs->count, 1);
 611                 fs->lock = RW_LOCK_UNLOCKED;
 612                 fs->umask = old->umask;
 613                 read_lock(&old->lock);
 614                 fs->rootmnt = mntget(old->rootmnt);
 615                 fs->root = dget(old->root);
 616                 fs->pwdmnt = mntget(old->pwdmnt);
 617                 fs->pwd = dget(old->pwd);
 618                 if (old->altroot) {
 619                         fs->altrootmnt = mntget(old->altrootmnt);
 620                         fs->altroot = dget(old->altroot);
 621                 } else {
 622                         fs->altrootmnt = NULL;
 623                         fs->altroot = NULL;
 624                 }
 625                 read_unlock(&old->lock);
 626         }
 627         return fs;
 628 }
 629
 630 struct fs_struct *copy_fs_struct(struct fs_struct *old)
 631 {
 632         return __copy_fs_struct(old);
 633 }
 634
 635 EXPORT_SYMBOL_GPL(copy_fs_struct);
 636
 637 static inline int copy_fs(unsigned long clone_flags, struct task_struct * tsk)
 638 {
 639         if (clone_flags & CLONE_FS) {
 640                 atomic_inc(&current->fs->count);
 641                 return 0;
 642         }
 643         tsk->fs = __copy_fs_struct(current->fs);
 644         if (!tsk->fs)
 645                 return -ENOMEM;
 646         return 0;
 647 }
 648
 649 static int count_open_files(struct files_struct *files, int size)
 650 {
 651         int i;
 652
 653         /* Find the last open fd */
 654         for (i = size/(8*sizeof(long)); i > 0; ) {
 655                 if (files->open_fds->fds_bits[--i])
 656                         break;
 657         }
 658         i = (i+1) * 8 * sizeof(long);
 659         return i;
 660 }
 661
 662 static int copy_files(unsigned long clone_flags, struct task_struct * tsk)
 663 {
 664         struct files_struct *oldf, *newf;
 665         struct file **old_fds, **new_fds;
 666         int open_files, nfds, size, i, error = 0;
 667
 668         /*
 669          * A background process may not have any files ...
 670          */
 671         oldf = current->files;
 672         if (!oldf)
 673                 goto out;
 674
 675         if (clone_flags & CLONE_FILES) {
 676                 atomic_inc(&oldf->count);
 677                 goto out;
 678         }
 679
 680         /*
 681          * Note: we may be using current for both targets (See exec.c)
 682          * This works because we cache current->files (old) as oldf. Don't
 683          * break this.
 684          */
 685         tsk->files = NULL;
 686         error = -ENOMEM;
 687         newf = kmem_cache_alloc(files_cachep, SLAB_KERNEL);
 688         if (!newf)
 689                 goto out;
 690
 691         atomic_set(&newf->count, 1);
 692
 693         newf->file_lock     = SPIN_LOCK_UNLOCKED;
 694         newf->next_fd       = 0;
 695         newf->max_fds       = NR_OPEN_DEFAULT;
 696         newf->max_fdset     = __FD_SETSIZE;
 697         newf->close_on_exec = &newf->close_on_exec_init;
 698         newf->open_fds      = &newf->open_fds_init;
 699         newf->fd            = &newf->fd_array[0];
 700
 701         /* We don't yet have the oldf readlock, but even if the old
 702            fdset gets grown now, we'll only copy up to "size" fds */
 703         size = oldf->max_fdset;
 704         if (size > __FD_SETSIZE) {
 705                 newf->max_fdset = 0;
 706                 spin_lock(&newf->file_lock);
 707                 error = expand_fdset(newf, size-1);
 708                 spin_unlock(&newf->file_lock);
 709                 if (error)
 710                         goto out_release;
 711         }
 712         spin_lock(&oldf->file_lock);
 713
 714         open_files = count_open_files(oldf, size);
 715
 716         /*
 717          * Check whether we need to allocate a larger fd array.
 718          * Note: we're not a clone task, so the open count won't
 719          * change.
 720          */
 721         nfds = NR_OPEN_DEFAULT;
 722         if (open_files > nfds) {
 723                 spin_unlock(&oldf->file_lock);
 724                 newf->max_fds = 0;
 725                 spin_lock(&newf->file_lock);
 726                 error = expand_fd_array(newf, open_files-1);
 727                 spin_unlock(&newf->file_lock);
 728                 if (error)
 729                         goto out_release;
 730                 nfds = newf->max_fds;
 731                 spin_lock(&oldf->file_lock);
 732         }
 733
 734         old_fds = oldf->fd;
 735         new_fds = newf->fd;
 736
 737         memcpy(newf->open_fds->fds_bits, oldf->open_fds->fds_bits, open_files/8);
 738         memcpy(newf->close_on_exec->fds_bits, oldf->close_on_exec->fds_bits, open_files/8);
 739
 740         for (i = open_files; i != 0; i--) {
 741                 struct file *f = *old_fds++;
 742                 if (f)
 743                         get_file(f);
 744                 *new_fds++ = f;
 745         }
 746         spin_unlock(&oldf->file_lock);
 747
 748         /* compute the remainder to be cleared */
 749         size = (newf->max_fds - open_files) * sizeof(struct file *);
 750
 751         /* This is long word aligned thus could use a optimized version */
 752         memset(new_fds, 0, size);
 753
 754         if (newf->max_fdset > open_files) {
 755                 int left = (newf->max_fdset-open_files)/8;
 756                 int start = open_files / (8 * sizeof(unsigned long));
 757
 758                 memset(&newf->open_fds->fds_bits[start], 0, left);
 759                 memset(&newf->close_on_exec->fds_bits[start], 0, left);
 760         }
 761
 762         tsk->files = newf;
 763         error = 0;
 764 out:
 765         return error;
 766
 767 out_release:
 768         free_fdset (newf->close_on_exec, newf->max_fdset);
 769         free_fdset (newf->open_fds, newf->max_fdset);
 770         kmem_cache_free(files_cachep, newf);
 771         goto out;
 772 }
 773
 774 /*
 775  *      Helper to unshare the files of the current task.
 776  *      We don't want to expose copy_files internals to
 777  *      the exec layer of the kernel.
 778  */
 779
 780 int unshare_files(void)
 781 {
 782         struct files_struct *files  = current->files;
 783         int rc;
 784
 785         if(!files)
 786                 BUG();
 787
 788         /* This can race but the race causes us to copy when we don't
 789            need to and drop the copy */
 790         if(atomic_read(&files->count) == 1)
 791         {
 792                 atomic_inc(&files->count);
 793                 return 0;
 794         }
 795         rc = copy_files(0, current);
 796         if(rc)
 797                 current->files = files;
 798         return rc;
 799 }
 800
 801 EXPORT_SYMBOL(unshare_files);
 802
 803 static inline int copy_sighand(unsigned long clone_flags, struct task_struct * tsk)
 804 {
 805         struct sighand_struct *sig;
 806
 807         if (clone_flags & (CLONE_SIGHAND | CLONE_THREAD)) {
 808                 atomic_inc(&current->sighand->count);
 809                 return 0;
 810         }
 811         sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
 812         tsk->sighand = sig;
 813         if (!sig)
 814                 return -ENOMEM;
 815         spin_lock_init(&sig->siglock);
 816         atomic_set(&sig->count, 1);
 817         memcpy(sig->action, current->sighand->action, sizeof(sig->action));
 818         return 0;
 819 }
 820
 821 static inline int copy_signal(unsigned long clone_flags, struct task_struct * tsk)
 822 {
 823         struct signal_struct *sig;
 824
 825         if (clone_flags & CLONE_THREAD) {
 826                 atomic_inc(&current->signal->count);
 827                 return 0;
 828         }
 829         sig = kmem_cache_alloc(signal_cachep, GFP_KERNEL);
 830         tsk->signal = sig;
 831         if (!sig)
 832                 return -ENOMEM;
 833         atomic_set(&sig->count, 1);
 834         sig->group_exit = 0;
 835         sig->group_exit_code = 0;
 836         sig->group_exit_task = NULL;
 837         sig->group_stop_count = 0;
 838         sig->curr_target = NULL;
 839         init_sigpending(&sig->shared_pending);
 840         INIT_LIST_HEAD(&sig->posix_timers);
 841
 842         sig->tty = current->signal->tty;
 843         sig->pgrp = process_group(current);
 844         sig->session = current->signal->session;
 845         sig->leader = 0;        /* session leadership doesn't inherit */
 846         sig->tty_old_pgrp = 0;
 847
 848         return 0;
 849 }
 850
 851 static inline void copy_flags(unsigned long clone_flags, struct task_struct *p)
 852 {
 853         unsigned long new_flags = p->flags;
 854
 855         new_flags &= ~PF_SUPERPRIV;
 856         new_flags |= PF_FORKNOEXEC;
 857         if (!(clone_flags & CLONE_PTRACE))
 858                 p->ptrace = 0;
 859         p->flags = new_flags;
 860 }
 861
 862 asmlinkage long sys_set_tid_address(int __user *tidptr)
 863 {
 864         current->clear_child_tid = tidptr;
 865
 866         return current->pid;
 867 }
 868
 869 /*
 870  * This creates a new process as a copy of the old one,
 871  * but does not actually start it yet.
 872  *
 873  * It copies the registers, and all the appropriate
 874  * parts of the process environment (as per the clone
 875  * flags). The actual kick-off is left to the caller.
 876  */
 877 struct task_struct *copy_process(unsigned long clone_flags,
 878                                  unsigned long stack_start,
 879                                  struct pt_regs *regs,
 880                                  unsigned long stack_size,
 881                                  int __user *parent_tidptr,
 882                                  int __user *child_tidptr)
 883 {
 884         int retval;
 885         struct task_struct *p = NULL;
 886         struct vx_info *vxi;
 887
 888         if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS))
 889                 return ERR_PTR(-EINVAL);
 890
 891         /*
 892          * Thread groups must share signals as well, and detached threads
 893          * can only be started up within the thread group.
 894          */
 895         if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND))
 896                 return ERR_PTR(-EINVAL);
 897
 898         /*
 899          * Shared signal handlers imply shared VM. By way of the above,
 900          * thread groups also imply shared VM. Blocking this case allows
 901          * for various simplifications in other code.
 902          */
 903         if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM))
 904                 return ERR_PTR(-EINVAL);
 905
 906         retval = security_task_create(clone_flags);
 907         if (retval)
 908                 goto fork_out;
 909
 910         retval = -ENOMEM;
 911
 912         p = dup_task_struct(current);
 913         if (!p)
 914                 goto fork_out;
 915         p->tux_info = NULL;
 916
 917         p->vx_info = NULL;
 918         set_vx_info(&p->vx_info, current->vx_info);
 919         p->nx_info = NULL;
 920         set_nx_info(&p->nx_info, current->nx_info);
 921
 922         /* check vserver memory */
 923         if (p->mm && !(clone_flags & CLONE_VM)) {
 924                 if (vx_vmpages_avail(p->mm, p->mm->total_vm))
 925                         vx_pages_add(p->mm->mm_vx_info, RLIMIT_AS, p->mm->total_vm);
 926                 else
 927                         goto bad_fork_free;
 928         }
 929         if (p->mm && vx_flags(VXF_FORK_RSS, 0)) {
 930                 if (!vx_rsspages_avail(p->mm, p->mm->rss))
 931                         goto bad_fork_free;
 932         }
 933
 934         retval = -EAGAIN;
 935         vxi = current->vx_info;
 936         if (vxi && (atomic_read(&vxi->limit.res[RLIMIT_NPROC])
 937                 >= vxi->limit.rlim[RLIMIT_NPROC]))
 938                 goto bad_fork_free;
 939
 940         if (atomic_read(&p->user->processes) >=
 941                         p->rlim[RLIMIT_NPROC].rlim_cur) {
 942                 if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_RESOURCE) &&
 943                                 p->user != &root_user)
 944                         goto bad_fork_free;
 945         }
 946
 947         atomic_inc(&p->user->__count);
 948         atomic_inc(&p->user->processes);
 949         get_group_info(p->group_info);
 950
 951         /*
 952          * If multiple threads are within copy_process(), then this check
 953          * triggers too late. This doesn't hurt, the check is only there
 954          * to stop root fork bombs.
 955          */
 956         if (nr_threads >= max_threads)
 957                 goto bad_fork_cleanup_count;
 958
 959         if (!try_module_get(p->thread_info->exec_domain->module))
 960                 goto bad_fork_cleanup_count;
 961
 962         if (p->binfmt && !try_module_get(p->binfmt->module))
 963                 goto bad_fork_cleanup_put_domain;
 964
 965         p->did_exec = 0;
 966         copy_flags(clone_flags, p);
 967         if (clone_flags & CLONE_IDLETASK)
 968                 p->pid = 0;
 969         else {
 970                 p->pid = alloc_pidmap();
 971                 if (p->pid == -1)
 972                         goto bad_fork_cleanup;
 973         }
 974         retval = -EFAULT;
 975         if (clone_flags & CLONE_PARENT_SETTID)
 976                 if (put_user(p->pid, parent_tidptr))
 977                         goto bad_fork_cleanup;
 978
 979         p->proc_dentry = NULL;
 980
 981         INIT_LIST_HEAD(&p->children);
 982         INIT_LIST_HEAD(&p->sibling);
 983         init_waitqueue_head(&p->wait_chldexit);
 984         p->vfork_done = NULL;
 985         spin_lock_init(&p->alloc_lock);
 986         spin_lock_init(&p->proc_lock);
 987
 988         clear_tsk_thread_flag(p, TIF_SIGPENDING);
 989         init_sigpending(&p->pending);
 990
 991         p->it_real_value = p->it_virt_value = p->it_prof_value = 0;
 992         p->it_real_incr = p->it_virt_incr = p->it_prof_incr = 0;
 993         init_timer(&p->real_timer);
 994         p->real_timer.data = (unsigned long) p;
 995
 996         p->utime = p->stime = 0;
 997         p->cutime = p->cstime = 0;
 998         p->lock_depth = -1;             /* -1 = no lock */
 999         p->start_time = get_jiffies_64();
1000         p->security = NULL;
1001         p->io_context = NULL;
1002         p->audit_context = NULL;
1003 #ifdef CONFIG_NUMA
1004         p->mempolicy = mpol_copy(p->mempolicy);
1005         if (IS_ERR(p->mempolicy)) {
1006                 retval = PTR_ERR(p->mempolicy);
1007                 p->mempolicy = NULL;
1008                 goto bad_fork_cleanup;
1009         }
1010 #endif
1011
1012         retval = -ENOMEM;
1013         if ((retval = security_task_alloc(p)))
1014                 goto bad_fork_cleanup_policy;
1015         if ((retval = audit_alloc(p)))
1016                 goto bad_fork_cleanup_security;
1017         /* copy all the process information */
1018         if ((retval = copy_semundo(clone_flags, p)))
1019                 goto bad_fork_cleanup_audit;
1020         if ((retval = copy_files(clone_flags, p)))
1021                 goto bad_fork_cleanup_semundo;
1022         if ((retval = copy_fs(clone_flags, p)))
1023                 goto bad_fork_cleanup_files;
1024         if ((retval = copy_sighand(clone_flags, p)))
1025                 goto bad_fork_cleanup_fs;
1026         if ((retval = copy_signal(clone_flags, p)))
1027                 goto bad_fork_cleanup_sighand;
1028         if ((retval = copy_mm(clone_flags, p)))
1029                 goto bad_fork_cleanup_signal;
1030         if ((retval = copy_namespace(clone_flags, p)))
1031                 goto bad_fork_cleanup_mm;
1032         retval = copy_thread(0, clone_flags, stack_start, stack_size, p, regs);
1033         if (retval)
1034                 goto bad_fork_cleanup_namespace;
1035
1036         p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL;
1037         /*
1038          * Clear TID on mm_release()?
1039          */
1040         p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr: NULL;
1041
1042         /*
1043          * Syscall tracing should be turned off in the child regardless
1044          * of CLONE_PTRACE.
1045          */
1046         clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE);
1047
1048         /* Our parent execution domain becomes current domain
1049            These must match for thread signalling to apply */
1050
1051         p->parent_exec_id = p->self_exec_id;
1052
1053         /* ok, now we should be set up.. */
1054         p->exit_signal = (clone_flags & CLONE_THREAD) ? -1 : (clone_flags & CSIGNAL);
1055         p->pdeath_signal = 0;
1056
1057         /* Perform scheduler related setup */
1058         sched_fork(p);
1059
1060         /*
1061          * Ok, make it visible to the rest of the system.
1062          * We dont wake it up yet.
1063          */
1064         p->tgid = p->pid;
1065         p->group_leader = p;
1066         INIT_LIST_HEAD(&p->ptrace_children);
1067         INIT_LIST_HEAD(&p->ptrace_list);
1068
1069         /* Need tasklist lock for parent etc handling! */
1070         write_lock_irq(&tasklist_lock);
1071         /*
1072          * Check for pending SIGKILL! The new thread should not be allowed
1073          * to slip out of an OOM kill. (or normal SIGKILL.)
1074          */
1075         if (sigismember(&current->pending.signal, SIGKILL)) {
1076                 write_unlock_irq(&tasklist_lock);
1077                 retval = -EINTR;
1078                 goto bad_fork_cleanup_namespace;
1079         }
1080
1081         /* CLONE_PARENT re-uses the old parent */
1082         if (clone_flags & CLONE_PARENT)
1083                 p->real_parent = current->real_parent;
1084         else
1085                 p->real_parent = current;
1086         p->parent = p->real_parent;
1087
1088         if (clone_flags & CLONE_THREAD) {
1089                 spin_lock(&current->sighand->siglock);
1090                 /*
1091                  * Important: if an exit-all has been started then
1092                  * do not create this new thread - the whole thread
1093                  * group is supposed to exit anyway.
1094                  */
1095                 if (current->signal->group_exit) {
1096                         spin_unlock(&current->sighand->siglock);
1097                         write_unlock_irq(&tasklist_lock);
1098                         retval = -EAGAIN;
1099                         goto bad_fork_cleanup_namespace;
1100                 }
1101                 p->tgid = current->tgid;
1102                 p->group_leader = current->group_leader;
1103
1104                 if (current->signal->group_stop_count > 0) {
1105                         /*
1106                          * There is an all-stop in progress for the group.
1107                          * We ourselves will stop as soon as we check signals.
1108                          * Make the new thread part of that group stop too.
1109                          */
1110                         current->signal->group_stop_count++;
1111                         set_tsk_thread_flag(p, TIF_SIGPENDING);
1112                 }
1113
1114                 spin_unlock(&current->sighand->siglock);
1115         }
1116
1117         SET_LINKS(p);
1118         if (p->ptrace & PT_PTRACED)
1119                 __ptrace_link(p, current->parent);
1120
1121         attach_pid(p, PIDTYPE_PID, p->pid);
1122         if (thread_group_leader(p)) {
1123                 attach_pid(p, PIDTYPE_TGID, p->tgid);
1124                 attach_pid(p, PIDTYPE_PGID, process_group(p));
1125                 attach_pid(p, PIDTYPE_SID, p->signal->session);
1126                 if (p->pid)
1127                         __get_cpu_var(process_counts)++;
1128         } else
1129                 link_pid(p, p->pids + PIDTYPE_TGID, &p->group_leader->pids[PIDTYPE_TGID].pid);
1130
1131         nr_threads++;
1132         if (vxi) {
1133                 atomic_inc(&vxi->cacct.nr_threads);
1134                 atomic_inc(&vxi->limit.res[RLIMIT_NPROC]);
1135         }
1136         write_unlock_irq(&tasklist_lock);
1137         retval = 0;
1138
1139 fork_out:
1140         if (retval)
1141                 return ERR_PTR(retval);
1142         return p;
1143
1144 bad_fork_cleanup_namespace:
1145         exit_namespace(p);
1146 bad_fork_cleanup_mm:
1147         exit_mm(p);
1148         if (p->active_mm)
1149                 mmdrop(p->active_mm);
1150 bad_fork_cleanup_signal:
1151         exit_signal(p);
1152 bad_fork_cleanup_sighand:
1153         exit_sighand(p);
1154 bad_fork_cleanup_fs:
1155         exit_fs(p); /* blocking */
1156 bad_fork_cleanup_files:
1157         exit_files(p); /* blocking */
1158 bad_fork_cleanup_semundo:
1159         exit_sem(p);
1160 bad_fork_cleanup_audit:
1161         audit_free(p);
1162 bad_fork_cleanup_security:
1163         security_task_free(p);
1164 bad_fork_cleanup_policy:
1165 #ifdef CONFIG_NUMA
1166         mpol_free(p->mempolicy);
1167 #endif
1168 bad_fork_cleanup:
1169         if (p->pid > 0)
1170                 free_pidmap(p->pid);
1171         if (p->binfmt)
1172                 module_put(p->binfmt->module);
1173 bad_fork_cleanup_put_domain:
1174         module_put(p->thread_info->exec_domain->module);
1175 bad_fork_cleanup_count:
1176         put_group_info(p->group_info);
1177         atomic_dec(&p->user->processes);
1178         free_uid(p->user);
1179 bad_fork_free:
1180         free_task(p);
1181         goto fork_out;
1182 }
1183
1184 static inline int fork_traceflag (unsigned clone_flags)
1185 {
1186         if (clone_flags & (CLONE_UNTRACED | CLONE_IDLETASK))
1187                 return 0;
1188         else if (clone_flags & CLONE_VFORK) {
1189                 if (current->ptrace & PT_TRACE_VFORK)
1190                         return PTRACE_EVENT_VFORK;
1191         } else if ((clone_flags & CSIGNAL) != SIGCHLD) {
1192                 if (current->ptrace & PT_TRACE_CLONE)
1193                         return PTRACE_EVENT_CLONE;
1194         } else if (current->ptrace & PT_TRACE_FORK)
1195                 return PTRACE_EVENT_FORK;
1196
1197         return 0;
1198 }
1199
1200 /*
1201  *  Ok, this is the main fork-routine.
1202  *
1203  * It copies the process, and if successful kick-starts
1204  * it and waits for it to finish using the VM if required.
1205  */
1206 long do_fork(unsigned long clone_flags,
1207               unsigned long stack_start,
1208               struct pt_regs *regs,
1209               unsigned long stack_size,
1210               int __user *parent_tidptr,
1211               int __user *child_tidptr)
1212 {
1213         struct task_struct *p;
1214         int trace = 0;
1215         long pid;
1216
1217         if (unlikely(current->ptrace)) {
1218                 trace = fork_traceflag (clone_flags);
1219                 if (trace)
1220                         clone_flags |= CLONE_PTRACE;
1221         }
1222
1223         p = copy_process(clone_flags, stack_start, regs, stack_size, parent_tidptr, child_tidptr);
1224         /*
1225          * Do this prior waking up the new thread - the thread pointer
1226          * might get invalid after that point, if the thread exits quickly.
1227          */
1228         pid = IS_ERR(p) ? PTR_ERR(p) : p->pid;
1229
1230         if (!IS_ERR(p)) {
1231                 struct completion vfork;
1232
1233                 if (clone_flags & CLONE_VFORK) {
1234                         p->vfork_done = &vfork;
1235                         init_completion(&vfork);
1236                 }
1237
1238                 if ((p->ptrace & PT_PTRACED) || (clone_flags & CLONE_STOPPED)) {
1239                         /*
1240                          * We'll start up with an immediate SIGSTOP.
1241                          */
1242                         sigaddset(&p->pending.signal, SIGSTOP);
1243                         set_tsk_thread_flag(p, TIF_SIGPENDING);
1244                 }
1245
1246                 if (!(clone_flags & CLONE_STOPPED)) {
1247                         /*
1248                          * Do the wakeup last. On SMP we treat fork() and
1249                          * CLONE_VM separately, because fork() has already
1250                          * created cache footprint on this CPU (due to
1251                          * copying the pagetables), hence migration would
1252                          * probably be costy. Threads on the other hand
1253                          * have less traction to the current CPU, and if
1254                          * there's an imbalance then the scheduler can
1255                          * migrate this fresh thread now, before it
1256                          * accumulates a larger cache footprint:
1257                          */
1258                         if (clone_flags & CLONE_VM)
1259                                 wake_up_forked_thread(p);
1260                         else
1261                                 wake_up_forked_process(p);
1262                 } else {
1263                         int cpu = get_cpu();
1264
1265                         p->state = TASK_STOPPED;
1266                         if (cpu_is_offline(task_cpu(p)))
1267                                 set_task_cpu(p, cpu);
1268
1269                         put_cpu();
1270                 }
1271                 ++total_forks;
1272
1273                 if (unlikely (trace)) {
1274                         current->ptrace_message = pid;
1275                         ptrace_notify ((trace << 8) | SIGTRAP);
1276                 }
1277
1278                 if (clone_flags & CLONE_VFORK) {
1279                         wait_for_completion(&vfork);
1280                         if (unlikely (current->ptrace & PT_TRACE_VFORK_DONE))
1281                                 ptrace_notify ((PTRACE_EVENT_VFORK_DONE << 8) | SIGTRAP);
1282                 } else
1283                         /*
1284                          * Let the child process run first, to avoid most of the
1285                          * COW overhead when the child exec()s afterwards.
1286                          */
1287                         set_need_resched();
1288         }
1289         return pid;
1290 }
1291
1292 /* SLAB cache for signal_struct structures (tsk->signal) */
1293 kmem_cache_t *signal_cachep;
1294
1295 /* SLAB cache for sighand_struct structures (tsk->sighand) */
1296 kmem_cache_t *sighand_cachep;
1297
1298 /* SLAB cache for files_struct structures (tsk->files) */
1299 kmem_cache_t *files_cachep;
1300
1301 /* SLAB cache for fs_struct structures (tsk->fs) */
1302 kmem_cache_t *fs_cachep;
1303
1304 /* SLAB cache for vm_area_struct structures */
1305 kmem_cache_t *vm_area_cachep;
1306
1307 /* SLAB cache for mm_struct structures (tsk->mm) */
1308 kmem_cache_t *mm_cachep;
1309
1310 void __init proc_caches_init(void)
1311 {
1312         sighand_cachep = kmem_cache_create("sighand_cache",
1313                         sizeof(struct sighand_struct), 0,
1314                         SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
1315         signal_cachep = kmem_cache_create("signal_cache",
1316                         sizeof(struct signal_struct), 0,
1317                         SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
1318         files_cachep = kmem_cache_create("files_cache",
1319                         sizeof(struct files_struct), 0,
1320                         SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
1321         fs_cachep = kmem_cache_create("fs_cache",
1322                         sizeof(struct fs_struct), 0,
1323                         SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
1324         vm_area_cachep = kmem_cache_create("vm_area_struct",
1325                         sizeof(struct vm_area_struct), 0,
1326                         SLAB_PANIC, NULL, NULL);
1327         mm_cachep = kmem_cache_create("mm_struct",
1328                         sizeof(struct mm_struct), 0,
1329                         SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
1330 }