File: /usr/src/linux/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/personality.h>
23
24 #include <asm/pgtable.h>
25 #include <asm/pgalloc.h>
26 #include <asm/uaccess.h>
27 #include <asm/mmu_context.h>
28
29 /* The idle threads do not count.. */
30 int nr_threads;
31 int nr_running;
32
33 int max_threads;
34 unsigned long total_forks; /* Handle normal Linux uptimes. */
35 int last_pid;
36
37 struct task_struct *pidhash[PIDHASH_SZ];
38
39 void add_wait_queue(wait_queue_head_t *q, wait_queue_t * wait)
40 {
41 unsigned long flags;
42
43 wait->flags &= ~WQ_FLAG_EXCLUSIVE;
44 wq_write_lock_irqsave(&q->lock, flags);
45 __add_wait_queue(q, wait);
46 wq_write_unlock_irqrestore(&q->lock, flags);
47 }
48
49 void add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t * wait)
50 {
51 unsigned long flags;
52
53 wait->flags |= WQ_FLAG_EXCLUSIVE;
54 wq_write_lock_irqsave(&q->lock, flags);
55 __add_wait_queue_tail(q, wait);
56 wq_write_unlock_irqrestore(&q->lock, flags);
57 }
58
59 void remove_wait_queue(wait_queue_head_t *q, wait_queue_t * wait)
60 {
61 unsigned long flags;
62
63 wq_write_lock_irqsave(&q->lock, flags);
64 __remove_wait_queue(q, wait);
65 wq_write_unlock_irqrestore(&q->lock, flags);
66 }
67
68 void __init fork_init(unsigned long mempages)
69 {
70 /*
71 * The default maximum number of threads is set to a safe
72 * value: the thread structures can take up at most half
73 * of memory.
74 */
75 max_threads = mempages / (THREAD_SIZE/PAGE_SIZE) / 8;
76
77 init_task.rlim[RLIMIT_NPROC].rlim_cur = max_threads/2;
78 init_task.rlim[RLIMIT_NPROC].rlim_max = max_threads/2;
79 }
80
81 /* Protects next_safe and last_pid. */
82 spinlock_t lastpid_lock = SPIN_LOCK_UNLOCKED;
83
84 static int get_pid(unsigned long flags)
85 {
86 static int next_safe = PID_MAX;
87 struct task_struct *p;
88
89 if (flags & CLONE_PID)
90 return current->pid;
91
92 spin_lock(&lastpid_lock);
93 if((++last_pid) & 0xffff8000) {
94 last_pid = 300; /* Skip daemons etc. */
95 goto inside;
96 }
97 if(last_pid >= next_safe) {
98 inside:
99 next_safe = PID_MAX;
100 read_lock(&tasklist_lock);
101 repeat:
102 for_each_task(p) {
103 if(p->pid == last_pid ||
104 p->pgrp == last_pid ||
105 p->tgid == last_pid ||
106 p->session == last_pid) {
107 if(++last_pid >= next_safe) {
108 if(last_pid & 0xffff8000)
109 last_pid = 300;
110 next_safe = PID_MAX;
111 }
112 goto repeat;
113 }
114 if(p->pid > last_pid && next_safe > p->pid)
115 next_safe = p->pid;
116 if(p->pgrp > last_pid && next_safe > p->pgrp)
117 next_safe = p->pgrp;
118 if(p->session > last_pid && next_safe > p->session)
119 next_safe = p->session;
120 }
121 read_unlock(&tasklist_lock);
122 }
123 spin_unlock(&lastpid_lock);
124
125 return last_pid;
126 }
127
128 static inline int dup_mmap(struct mm_struct * mm)
129 {
130 struct vm_area_struct * mpnt, *tmp, **pprev;
131 int retval;
132
133 flush_cache_mm(current->mm);
134 mm->locked_vm = 0;
135 mm->mmap = NULL;
136 mm->mmap_cache = NULL;
137 mm->map_count = 0;
138 mm->rss = 0;
139 mm->cpu_vm_mask = 0;
140 mm->swap_address = 0;
141 pprev = &mm->mmap;
142
143 /*
144 * Add it to the mmlist after the parent.
145 * Doing it this way means that we can order the list,
146 * and fork() won't mess up the ordering significantly.
147 * Add it first so that swapoff can see any swap entries.
148 */
149 spin_lock(&mmlist_lock);
150 list_add(&mm->mmlist, ¤t->mm->mmlist);
151 mmlist_nr++;
152 spin_unlock(&mmlist_lock);
153
154 for (mpnt = current->mm->mmap ; mpnt ; mpnt = mpnt->vm_next) {
155 struct file *file;
156
157 retval = -ENOMEM;
158 if(mpnt->vm_flags & VM_DONTCOPY)
159 continue;
160 tmp = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
161 if (!tmp)
162 goto fail_nomem;
163 *tmp = *mpnt;
164 tmp->vm_flags &= ~VM_LOCKED;
165 tmp->vm_mm = mm;
166 tmp->vm_next = NULL;
167 file = tmp->vm_file;
168 if (file) {
169 struct inode *inode = file->f_dentry->d_inode;
170 get_file(file);
171 if (tmp->vm_flags & VM_DENYWRITE)
172 atomic_dec(&inode->i_writecount);
173
174 /* insert tmp into the share list, just after mpnt */
175 spin_lock(&inode->i_mapping->i_shared_lock);
176 if((tmp->vm_next_share = mpnt->vm_next_share) != NULL)
177 mpnt->vm_next_share->vm_pprev_share =
178 &tmp->vm_next_share;
179 mpnt->vm_next_share = tmp;
180 tmp->vm_pprev_share = &mpnt->vm_next_share;
181 spin_unlock(&inode->i_mapping->i_shared_lock);
182 }
183
184 /*
185 * Link in the new vma and copy the page table entries:
186 * link in first so that swapoff can see swap entries.
187 */
188 spin_lock(&mm->page_table_lock);
189 *pprev = tmp;
190 pprev = &tmp->vm_next;
191 mm->map_count++;
192 retval = copy_page_range(mm, current->mm, tmp);
193 spin_unlock(&mm->page_table_lock);
194
195 if (tmp->vm_ops && tmp->vm_ops->open)
196 tmp->vm_ops->open(tmp);
197
198 if (retval)
199 goto fail_nomem;
200 }
201 retval = 0;
202 build_mmap_rb(mm);
203
204 fail_nomem:
205 flush_tlb_mm(current->mm);
206 return retval;
207 }
208
209 spinlock_t mmlist_lock __cacheline_aligned = SPIN_LOCK_UNLOCKED;
210 int mmlist_nr;
211
212 #define allocate_mm() (kmem_cache_alloc(mm_cachep, SLAB_KERNEL))
213 #define free_mm(mm) (kmem_cache_free(mm_cachep, (mm)))
214
215 static struct mm_struct * mm_init(struct mm_struct * mm)
216 {
217 atomic_set(&mm->mm_users, 1);
218 atomic_set(&mm->mm_count, 1);
219 init_rwsem(&mm->mmap_sem);
220 mm->page_table_lock = SPIN_LOCK_UNLOCKED;
221 mm->pgd = pgd_alloc(mm);
222 if (mm->pgd)
223 return mm;
224 free_mm(mm);
225 return NULL;
226 }
227
228
229 /*
230 * Allocate and initialize an mm_struct.
231 */
232 struct mm_struct * mm_alloc(void)
233 {
234 struct mm_struct * mm;
235
236 mm = allocate_mm();
237 if (mm) {
238 memset(mm, 0, sizeof(*mm));
239 return mm_init(mm);
240 }
241 return NULL;
242 }
243
244 /*
245 * Called when the last reference to the mm
246 * is dropped: either by a lazy thread or by
247 * mmput. Free the page directory and the mm.
248 */
249 inline void __mmdrop(struct mm_struct *mm)
250 {
251 if (mm == &init_mm) BUG();
252 pgd_free(mm->pgd);
253 destroy_context(mm);
254 free_mm(mm);
255 }
256
257 /*
258 * Decrement the use count and release all resources for an mm.
259 */
260 void mmput(struct mm_struct *mm)
261 {
262 if (atomic_dec_and_lock(&mm->mm_users, &mmlist_lock)) {
263 extern struct mm_struct *swap_mm;
264 if (swap_mm == mm)
265 swap_mm = list_entry(mm->mmlist.next, struct mm_struct, mmlist);
266 list_del(&mm->mmlist);
267 mmlist_nr--;
268 spin_unlock(&mmlist_lock);
269 exit_mmap(mm);
270 mmdrop(mm);
271 }
272 }
273
274 /* Please note the differences between mmput and mm_release.
275 * mmput is called whenever we stop holding onto a mm_struct,
276 * error success whatever.
277 *
278 * mm_release is called after a mm_struct has been removed
279 * from the current process.
280 *
281 * This difference is important for error handling, when we
282 * only half set up a mm_struct for a new process and need to restore
283 * the old one. Because we mmput the new mm_struct before
284 * restoring the old one. . .
285 * Eric Biederman 10 January 1998
286 */
287 void mm_release(void)
288 {
289 struct task_struct *tsk = current;
290 struct completion *vfork_done = tsk->vfork_done;
291
292 /* notify parent sleeping on vfork() */
293 if (vfork_done) {
294 tsk->vfork_done = NULL;
295 complete(vfork_done);
296 }
297 }
298
299 static int copy_mm(unsigned long clone_flags, struct task_struct * tsk)
300 {
301 struct mm_struct * mm, *oldmm;
302 int retval;
303
304 tsk->min_flt = tsk->maj_flt = 0;
305 tsk->cmin_flt = tsk->cmaj_flt = 0;
306 tsk->nswap = tsk->cnswap = 0;
307
308 tsk->mm = NULL;
309 tsk->active_mm = NULL;
310
311 /*
312 * Are we cloning a kernel thread?
313 *
314 * We need to steal a active VM for that..
315 */
316 oldmm = current->mm;
317 if (!oldmm)
318 return 0;
319
320 if (clone_flags & CLONE_VM) {
321 atomic_inc(&oldmm->mm_users);
322 mm = oldmm;
323 goto good_mm;
324 }
325
326 retval = -ENOMEM;
327 mm = allocate_mm();
328 if (!mm)
329 goto fail_nomem;
330
331 /* Copy the current MM stuff.. */
332 memcpy(mm, oldmm, sizeof(*mm));
333 if (!mm_init(mm))
334 goto fail_nomem;
335
336 down_write(&oldmm->mmap_sem);
337 retval = dup_mmap(mm);
338 up_write(&oldmm->mmap_sem);
339
340 if (retval)
341 goto free_pt;
342
343 /*
344 * child gets a private LDT (if there was an LDT in the parent)
345 */
346 copy_segments(tsk, mm);
347
348 if (init_new_context(tsk,mm))
349 goto free_pt;
350
351 good_mm:
352 tsk->mm = mm;
353 tsk->active_mm = mm;
354 return 0;
355
356 free_pt:
357 mmput(mm);
358 fail_nomem:
359 return retval;
360 }
361
362 static inline struct fs_struct *__copy_fs_struct(struct fs_struct *old)
363 {
364 struct fs_struct *fs = kmem_cache_alloc(fs_cachep, GFP_KERNEL);
365 /* We don't need to lock fs - think why ;-) */
366 if (fs) {
367 atomic_set(&fs->count, 1);
368 fs->lock = RW_LOCK_UNLOCKED;
369 fs->umask = old->umask;
370 read_lock(&old->lock);
371 fs->rootmnt = mntget(old->rootmnt);
372 fs->root = dget(old->root);
373 fs->pwdmnt = mntget(old->pwdmnt);
374 fs->pwd = dget(old->pwd);
375 if (old->altroot) {
376 fs->altrootmnt = mntget(old->altrootmnt);
377 fs->altroot = dget(old->altroot);
378 } else {
379 fs->altrootmnt = NULL;
380 fs->altroot = NULL;
381 }
382 read_unlock(&old->lock);
383 }
384 return fs;
385 }
386
387 struct fs_struct *copy_fs_struct(struct fs_struct *old)
388 {
389 return __copy_fs_struct(old);
390 }
391
392 static inline int copy_fs(unsigned long clone_flags, struct task_struct * tsk)
393 {
394 if (clone_flags & CLONE_FS) {
395 atomic_inc(¤t->fs->count);
396 return 0;
397 }
398 tsk->fs = __copy_fs_struct(current->fs);
399 if (!tsk->fs)
400 return -1;
401 return 0;
402 }
403
404 static int count_open_files(struct files_struct *files, int size)
405 {
406 int i;
407
408 /* Find the last open fd */
409 for (i = size/(8*sizeof(long)); i > 0; ) {
410 if (files->open_fds->fds_bits[--i])
411 break;
412 }
413 i = (i+1) * 8 * sizeof(long);
414 return i;
415 }
416
417 static int copy_files(unsigned long clone_flags, struct task_struct * tsk)
418 {
419 struct files_struct *oldf, *newf;
420 struct file **old_fds, **new_fds;
421 int open_files, nfds, size, i, error = 0;
422
423 /*
424 * A background process may not have any files ...
425 */
426 oldf = current->files;
427 if (!oldf)
428 goto out;
429
430 if (clone_flags & CLONE_FILES) {
431 atomic_inc(&oldf->count);
432 goto out;
433 }
434
435 tsk->files = NULL;
436 error = -ENOMEM;
437 newf = kmem_cache_alloc(files_cachep, SLAB_KERNEL);
438 if (!newf)
439 goto out;
440
441 atomic_set(&newf->count, 1);
442
443 newf->file_lock = RW_LOCK_UNLOCKED;
444 newf->next_fd = 0;
445 newf->max_fds = NR_OPEN_DEFAULT;
446 newf->max_fdset = __FD_SETSIZE;
447 newf->close_on_exec = &newf->close_on_exec_init;
448 newf->open_fds = &newf->open_fds_init;
449 newf->fd = &newf->fd_array[0];
450
451 /* We don't yet have the oldf readlock, but even if the old
452 fdset gets grown now, we'll only copy up to "size" fds */
453 size = oldf->max_fdset;
454 if (size > __FD_SETSIZE) {
455 newf->max_fdset = 0;
456 write_lock(&newf->file_lock);
457 error = expand_fdset(newf, size-1);
458 write_unlock(&newf->file_lock);
459 if (error)
460 goto out_release;
461 }
462 read_lock(&oldf->file_lock);
463
464 open_files = count_open_files(oldf, size);
465
466 /*
467 * Check whether we need to allocate a larger fd array.
468 * Note: we're not a clone task, so the open count won't
469 * change.
470 */
471 nfds = NR_OPEN_DEFAULT;
472 if (open_files > nfds) {
473 read_unlock(&oldf->file_lock);
474 newf->max_fds = 0;
475 write_lock(&newf->file_lock);
476 error = expand_fd_array(newf, open_files-1);
477 write_unlock(&newf->file_lock);
478 if (error)
479 goto out_release;
480 nfds = newf->max_fds;
481 read_lock(&oldf->file_lock);
482 }
483
484 old_fds = oldf->fd;
485 new_fds = newf->fd;
486
487 memcpy(newf->open_fds->fds_bits, oldf->open_fds->fds_bits, open_files/8);
488 memcpy(newf->close_on_exec->fds_bits, oldf->close_on_exec->fds_bits, open_files/8);
489
490 for (i = open_files; i != 0; i--) {
491 struct file *f = *old_fds++;
492 if (f)
493 get_file(f);
494 *new_fds++ = f;
495 }
496 read_unlock(&oldf->file_lock);
497
498 /* compute the remainder to be cleared */
499 size = (newf->max_fds - open_files) * sizeof(struct file *);
500
501 /* This is long word aligned thus could use a optimized version */
502 memset(new_fds, 0, size);
503
504 if (newf->max_fdset > open_files) {
505 int left = (newf->max_fdset-open_files)/8;
506 int start = open_files / (8 * sizeof(unsigned long));
507
508 memset(&newf->open_fds->fds_bits[start], 0, left);
509 memset(&newf->close_on_exec->fds_bits[start], 0, left);
510 }
511
512 tsk->files = newf;
513 error = 0;
514 out:
515 return error;
516
517 out_release:
518 free_fdset (newf->close_on_exec, newf->max_fdset);
519 free_fdset (newf->open_fds, newf->max_fdset);
520 kmem_cache_free(files_cachep, newf);
521 goto out;
522 }
523
524 static inline int copy_sighand(unsigned long clone_flags, struct task_struct * tsk)
525 {
526 struct signal_struct *sig;
527
528 if (clone_flags & CLONE_SIGHAND) {
529 atomic_inc(¤t->sig->count);
530 return 0;
531 }
532 sig = kmem_cache_alloc(sigact_cachep, GFP_KERNEL);
533 tsk->sig = sig;
534 if (!sig)
535 return -1;
536 spin_lock_init(&sig->siglock);
537 atomic_set(&sig->count, 1);
538 memcpy(tsk->sig->action, current->sig->action, sizeof(tsk->sig->action));
539 return 0;
540 }
541
542 static inline void copy_flags(unsigned long clone_flags, struct task_struct *p)
543 {
544 unsigned long new_flags = p->flags;
545
546 new_flags &= ~(PF_SUPERPRIV | PF_USEDFPU);
547 new_flags |= PF_FORKNOEXEC;
548 if (!(clone_flags & CLONE_PTRACE))
549 p->ptrace = 0;
550 p->flags = new_flags;
551 }
552
553 /*
554 * Ok, this is the main fork-routine. It copies the system process
555 * information (task[nr]) and sets up the necessary registers. It also
556 * copies the data segment in its entirety. The "stack_start" and
557 * "stack_top" arguments are simply passed along to the platform
558 * specific copy_thread() routine. Most platforms ignore stack_top.
559 * For an example that's using stack_top, see
560 * arch/ia64/kernel/process.c.
561 */
562 int do_fork(unsigned long clone_flags, unsigned long stack_start,
563 struct pt_regs *regs, unsigned long stack_size)
564 {
565 int retval;
566 struct task_struct *p;
567 struct completion vfork;
568
569 retval = -EPERM;
570
571 /*
572 * CLONE_PID is only allowed for the initial SMP swapper
573 * calls
574 */
575 if (clone_flags & CLONE_PID) {
576 if (current->pid)
577 goto fork_out;
578 }
579
580 retval = -ENOMEM;
581 p = alloc_task_struct();
582 if (!p)
583 goto fork_out;
584
585 *p = *current;
586
587 retval = -EAGAIN;
588 if (atomic_read(&p->user->processes) >= p->rlim[RLIMIT_NPROC].rlim_cur)
589 goto bad_fork_free;
590
591 atomic_inc(&p->user->__count);
592 atomic_inc(&p->user->processes);
593
594 /*
595 * Counter increases are protected by
596 * the kernel lock so nr_threads can't
597 * increase under us (but it may decrease).
598 */
599 if (nr_threads >= max_threads)
600 goto bad_fork_cleanup_count;
601
602 get_exec_domain(p->exec_domain);
603
604 if (p->binfmt && p->binfmt->module)
605 __MOD_INC_USE_COUNT(p->binfmt->module);
606
607 p->did_exec = 0;
608 p->swappable = 0;
609 p->state = TASK_UNINTERRUPTIBLE;
610
611 copy_flags(clone_flags, p);
612 p->pid = get_pid(clone_flags);
613
614 p->run_list.next = NULL;
615 p->run_list.prev = NULL;
616
617 p->p_cptr = NULL;
618 init_waitqueue_head(&p->wait_chldexit);
619 p->vfork_done = NULL;
620 if (clone_flags & CLONE_VFORK) {
621 p->vfork_done = &vfork;
622 init_completion(&vfork);
623 }
624 spin_lock_init(&p->alloc_lock);
625
626 p->sigpending = 0;
627 init_sigpending(&p->pending);
628
629 p->it_real_value = p->it_virt_value = p->it_prof_value = 0;
630 p->it_real_incr = p->it_virt_incr = p->it_prof_incr = 0;
631 init_timer(&p->real_timer);
632 p->real_timer.data = (unsigned long) p;
633
634 p->leader = 0; /* session leadership doesn't inherit */
635 p->tty_old_pgrp = 0;
636 p->times.tms_utime = p->times.tms_stime = 0;
637 p->times.tms_cutime = p->times.tms_cstime = 0;
638 #ifdef CONFIG_SMP
639 {
640 int i;
641 p->has_cpu = 0;
642 p->processor = current->processor;
643 /* ?? should we just memset this ?? */
644 for(i = 0; i < smp_num_cpus; i++)
645 p->per_cpu_utime[i] = p->per_cpu_stime[i] = 0;
646 spin_lock_init(&p->sigmask_lock);
647 }
648 #endif
649 p->lock_depth = -1; /* -1 = no lock */
650 p->start_time = jiffies;
651
652 INIT_LIST_HEAD(&p->local_pages);
653
654 retval = -ENOMEM;
655 /* copy all the process information */
656 if (copy_files(clone_flags, p))
657 goto bad_fork_cleanup;
658 if (copy_fs(clone_flags, p))
659 goto bad_fork_cleanup_files;
660 if (copy_sighand(clone_flags, p))
661 goto bad_fork_cleanup_fs;
662 if (copy_mm(clone_flags, p))
663 goto bad_fork_cleanup_sighand;
664 retval = copy_thread(0, clone_flags, stack_start, stack_size, p, regs);
665 if (retval)
666 goto bad_fork_cleanup_mm;
667 p->semundo = NULL;
668
669 /* Our parent execution domain becomes current domain
670 These must match for thread signalling to apply */
671
672 p->parent_exec_id = p->self_exec_id;
673
674 /* ok, now we should be set up.. */
675 p->swappable = 1;
676 p->exit_signal = clone_flags & CSIGNAL;
677 p->pdeath_signal = 0;
678
679 /*
680 * "share" dynamic priority between parent and child, thus the
681 * total amount of dynamic priorities in the system doesnt change,
682 * more scheduling fairness. This is only important in the first
683 * timeslice, on the long run the scheduling behaviour is unchanged.
684 */
685 p->counter = (current->counter + 1) >> 1;
686 current->counter >>= 1;
687 if (!current->counter)
688 current->need_resched = 1;
689
690 /*
691 * Ok, add it to the run-queues and make it
692 * visible to the rest of the system.
693 *
694 * Let it rip!
695 */
696 retval = p->pid;
697 p->tgid = retval;
698 INIT_LIST_HEAD(&p->thread_group);
699
700 /* Need tasklist lock for parent etc handling! */
701 write_lock_irq(&tasklist_lock);
702
703 /* CLONE_PARENT and CLONE_THREAD re-use the old parent */
704 p->p_opptr = current->p_opptr;
705 p->p_pptr = current->p_pptr;
706 if (!(clone_flags & (CLONE_PARENT | CLONE_THREAD))) {
707 p->p_opptr = current;
708 if (!(p->ptrace & PT_PTRACED))
709 p->p_pptr = current;
710 }
711
712 if (clone_flags & CLONE_THREAD) {
713 p->tgid = current->tgid;
714 list_add(&p->thread_group, ¤t->thread_group);
715 }
716
717 SET_LINKS(p);
718 hash_pid(p);
719 nr_threads++;
720 write_unlock_irq(&tasklist_lock);
721
722 if (p->ptrace & PT_PTRACED)
723 send_sig(SIGSTOP, p, 1);
724
725 wake_up_process(p); /* do this last */
726 ++total_forks;
727 if (clone_flags & CLONE_VFORK)
728 wait_for_completion(&vfork);
729
730 fork_out:
731 return retval;
732
733 bad_fork_cleanup_mm:
734 exit_mm(p);
735 bad_fork_cleanup_sighand:
736 exit_sighand(p);
737 bad_fork_cleanup_fs:
738 exit_fs(p); /* blocking */
739 bad_fork_cleanup_files:
740 exit_files(p); /* blocking */
741 bad_fork_cleanup:
742 put_exec_domain(p->exec_domain);
743 if (p->binfmt && p->binfmt->module)
744 __MOD_DEC_USE_COUNT(p->binfmt->module);
745 bad_fork_cleanup_count:
746 atomic_dec(&p->user->processes);
747 free_uid(p->user);
748 bad_fork_free:
749 free_task_struct(p);
750 goto fork_out;
751 }
752
753 /* SLAB cache for signal_struct structures (tsk->sig) */
754 kmem_cache_t *sigact_cachep;
755
756 /* SLAB cache for files_struct structures (tsk->files) */
757 kmem_cache_t *files_cachep;
758
759 /* SLAB cache for fs_struct structures (tsk->fs) */
760 kmem_cache_t *fs_cachep;
761
762 /* SLAB cache for vm_area_struct structures */
763 kmem_cache_t *vm_area_cachep;
764
765 /* SLAB cache for mm_struct structures (tsk->mm) */
766 kmem_cache_t *mm_cachep;
767
768 void __init proc_caches_init(void)
769 {
770 sigact_cachep = kmem_cache_create("signal_act",
771 sizeof(struct signal_struct), 0,
772 SLAB_HWCACHE_ALIGN, NULL, NULL);
773 if (!sigact_cachep)
774 panic("Cannot create signal action SLAB cache");
775
776 files_cachep = kmem_cache_create("files_cache",
777 sizeof(struct files_struct), 0,
778 SLAB_HWCACHE_ALIGN, NULL, NULL);
779 if (!files_cachep)
780 panic("Cannot create files SLAB cache");
781
782 fs_cachep = kmem_cache_create("fs_cache",
783 sizeof(struct fs_struct), 0,
784 SLAB_HWCACHE_ALIGN, NULL, NULL);
785 if (!fs_cachep)
786 panic("Cannot create fs_struct SLAB cache");
787
788 vm_area_cachep = kmem_cache_create("vm_area_struct",
789 sizeof(struct vm_area_struct), 0,
790 SLAB_HWCACHE_ALIGN, NULL, NULL);
791 if(!vm_area_cachep)
792 panic("vma_init: Cannot alloc vm_area_struct SLAB cache");
793
794 mm_cachep = kmem_cache_create("mm_struct",
795 sizeof(struct mm_struct), 0,
796 SLAB_HWCACHE_ALIGN, NULL, NULL);
797 if(!mm_cachep)
798 panic("vma_init: Cannot alloc mm_struct SLAB cache");
799 }
800