blob: facc1a75bd4fdbc9f274dbc26a7e536f0eb8f561 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * mm/mmap.c
3 *
4 * Written by obz.
5 *
6 * Address space accounting code <alan@redhat.com>
7 */
8
9#include <linux/slab.h>
Alexey Dobriyan4af3c9c2007-10-16 23:29:23 -070010#include <linux/backing-dev.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070011#include <linux/mm.h>
12#include <linux/shm.h>
13#include <linux/mman.h>
14#include <linux/pagemap.h>
15#include <linux/swap.h>
16#include <linux/syscalls.h>
Randy.Dunlapc59ede72006-01-11 12:17:46 -080017#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070018#include <linux/init.h>
19#include <linux/file.h>
20#include <linux/fs.h>
21#include <linux/personality.h>
22#include <linux/security.h>
23#include <linux/hugetlb.h>
24#include <linux/profile.h>
25#include <linux/module.h>
26#include <linux/mount.h>
27#include <linux/mempolicy.h>
28#include <linux/rmap.h>
29
30#include <asm/uaccess.h>
31#include <asm/cacheflush.h>
32#include <asm/tlb.h>
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +020033#include <asm/mmu_context.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070034
Kirill Korotaev3a459752006-09-07 14:17:04 +040035#ifndef arch_mmap_check
36#define arch_mmap_check(addr, len, flags) (0)
37#endif
38
Hugh Dickinse0da3822005-04-19 13:29:15 -070039static void unmap_region(struct mm_struct *mm,
40 struct vm_area_struct *vma, struct vm_area_struct *prev,
41 unsigned long start, unsigned long end);
42
Linus Torvalds1da177e2005-04-16 15:20:36 -070043/*
44 * WARNING: the debugging will use recursive algorithms so never enable this
45 * unless you know what you are doing.
46 */
47#undef DEBUG_MM_RB
48
49/* description of effects of mapping type and prot in current implementation.
50 * this is due to the limited x86 page protection hardware. The expected
51 * behavior is in parens:
52 *
53 * map_type prot
54 * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC
55 * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes
56 * w: (no) no w: (no) no w: (yes) yes w: (no) no
57 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
58 *
59 * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes
60 * w: (no) no w: (no) no w: (copy) copy w: (no) no
61 * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
62 *
63 */
64pgprot_t protection_map[16] = {
65 __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111,
66 __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
67};
68
Hugh Dickins804af2c2006-07-26 21:39:49 +010069pgprot_t vm_get_page_prot(unsigned long vm_flags)
70{
71 return protection_map[vm_flags &
72 (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)];
73}
74EXPORT_SYMBOL(vm_get_page_prot);
75
Linus Torvalds1da177e2005-04-16 15:20:36 -070076int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
77int sysctl_overcommit_ratio = 50; /* default is 50% */
Christoph Lameterc3d8c142005-09-06 15:16:33 -070078int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
Linus Torvalds1da177e2005-04-16 15:20:36 -070079atomic_t vm_committed_space = ATOMIC_INIT(0);
80
81/*
82 * Check that a process has enough memory to allocate a new virtual
83 * mapping. 0 means there is enough memory for the allocation to
84 * succeed and -ENOMEM implies there is not.
85 *
86 * We currently support three overcommit policies, which are set via the
87 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
88 *
89 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
90 * Additional code 2002 Jul 20 by Robert Love.
91 *
92 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
93 *
94 * Note this is a helper function intended to be used by LSMs which
95 * wish to use this logic.
96 */
Alan Cox34b4e4a2007-08-22 14:01:28 -070097int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
Linus Torvalds1da177e2005-04-16 15:20:36 -070098{
99 unsigned long free, allowed;
100
101 vm_acct_memory(pages);
102
103 /*
104 * Sometimes we want to use more memory than we have
105 */
106 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
107 return 0;
108
109 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
110 unsigned long n;
111
Christoph Lameter347ce432006-06-30 01:55:35 -0700112 free = global_page_state(NR_FILE_PAGES);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113 free += nr_swap_pages;
114
115 /*
116 * Any slabs which are created with the
117 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
118 * which are reclaimable, under pressure. The dentry
119 * cache and most inode caches should fall into this
120 */
Christoph Lameter972d1a72006-09-25 23:31:51 -0700121 free += global_page_state(NR_SLAB_RECLAIMABLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122
123 /*
124 * Leave the last 3% for root
125 */
126 if (!cap_sys_admin)
127 free -= free / 32;
128
129 if (free > pages)
130 return 0;
131
132 /*
133 * nr_free_pages() is very expensive on large systems,
134 * only call if we're about to fail.
135 */
136 n = nr_free_pages();
Hideo AOKI6d9f7832006-04-10 22:53:00 -0700137
138 /*
139 * Leave reserved pages. The pages are not for anonymous pages.
140 */
141 if (n <= totalreserve_pages)
142 goto error;
143 else
144 n -= totalreserve_pages;
145
146 /*
147 * Leave the last 3% for root
148 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 if (!cap_sys_admin)
150 n -= n / 32;
151 free += n;
152
153 if (free > pages)
154 return 0;
Hideo AOKI6d9f7832006-04-10 22:53:00 -0700155
156 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157 }
158
159 allowed = (totalram_pages - hugetlb_total_pages())
160 * sysctl_overcommit_ratio / 100;
161 /*
162 * Leave the last 3% for root
163 */
164 if (!cap_sys_admin)
165 allowed -= allowed / 32;
166 allowed += total_swap_pages;
167
168 /* Don't let a single process grow too big:
169 leave 3% of the size of this process for other processes */
Alan Cox34b4e4a2007-08-22 14:01:28 -0700170 allowed -= mm->total_vm / 32;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171
Simon Derr2f60f8d2005-08-04 19:52:03 -0700172 /*
173 * cast `allowed' as a signed long because vm_committed_space
174 * sometimes has a negative value
175 */
176 if (atomic_read(&vm_committed_space) < (long)allowed)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177 return 0;
Hideo AOKI6d9f7832006-04-10 22:53:00 -0700178error:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179 vm_unacct_memory(pages);
180
181 return -ENOMEM;
182}
183
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184/*
185 * Requires inode->i_mapping->i_mmap_lock
186 */
187static void __remove_shared_vm_struct(struct vm_area_struct *vma,
188 struct file *file, struct address_space *mapping)
189{
190 if (vma->vm_flags & VM_DENYWRITE)
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800191 atomic_inc(&file->f_path.dentry->d_inode->i_writecount);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192 if (vma->vm_flags & VM_SHARED)
193 mapping->i_mmap_writable--;
194
195 flush_dcache_mmap_lock(mapping);
196 if (unlikely(vma->vm_flags & VM_NONLINEAR))
197 list_del_init(&vma->shared.vm_set.list);
198 else
199 vma_prio_tree_remove(vma, &mapping->i_mmap);
200 flush_dcache_mmap_unlock(mapping);
201}
202
203/*
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700204 * Unlink a file-based vm structure from its prio_tree, to hide
205 * vma from rmap and vmtruncate before freeing its page tables.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206 */
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700207void unlink_file_vma(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208{
209 struct file *file = vma->vm_file;
210
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211 if (file) {
212 struct address_space *mapping = file->f_mapping;
213 spin_lock(&mapping->i_mmap_lock);
214 __remove_shared_vm_struct(vma, file, mapping);
215 spin_unlock(&mapping->i_mmap_lock);
216 }
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700217}
218
219/*
220 * Close a vm structure and free it, returning the next.
221 */
222static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
223{
224 struct vm_area_struct *next = vma->vm_next;
225
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700226 might_sleep();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227 if (vma->vm_ops && vma->vm_ops->close)
228 vma->vm_ops->close(vma);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700229 if (vma->vm_file)
230 fput(vma->vm_file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231 mpol_free(vma_policy(vma));
232 kmem_cache_free(vm_area_cachep, vma);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -0700233 return next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234}
235
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236asmlinkage unsigned long sys_brk(unsigned long brk)
237{
238 unsigned long rlim, retval;
239 unsigned long newbrk, oldbrk;
240 struct mm_struct *mm = current->mm;
241
242 down_write(&mm->mmap_sem);
243
244 if (brk < mm->end_code)
245 goto out;
Ram Gupta1e624192006-04-10 22:52:57 -0700246
247 /*
248 * Check against rlimit here. If this check is done later after the test
249 * of oldbrk with newbrk then it can escape the test and let the data
250 * segment grow beyond its set limit the in case where the limit is
251 * not page aligned -Ram Gupta
252 */
253 rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
254 if (rlim < RLIM_INFINITY && brk - mm->start_data > rlim)
255 goto out;
256
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257 newbrk = PAGE_ALIGN(brk);
258 oldbrk = PAGE_ALIGN(mm->brk);
259 if (oldbrk == newbrk)
260 goto set_brk;
261
262 /* Always allow shrinking brk. */
263 if (brk <= mm->brk) {
264 if (!do_munmap(mm, newbrk, oldbrk-newbrk))
265 goto set_brk;
266 goto out;
267 }
268
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269 /* Check against existing mmap mappings. */
270 if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE))
271 goto out;
272
273 /* Ok, looks good - let it rip. */
274 if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk)
275 goto out;
276set_brk:
277 mm->brk = brk;
278out:
279 retval = mm->brk;
280 up_write(&mm->mmap_sem);
281 return retval;
282}
283
284#ifdef DEBUG_MM_RB
285static int browse_rb(struct rb_root *root)
286{
287 int i = 0, j;
288 struct rb_node *nd, *pn = NULL;
289 unsigned long prev = 0, pend = 0;
290
291 for (nd = rb_first(root); nd; nd = rb_next(nd)) {
292 struct vm_area_struct *vma;
293 vma = rb_entry(nd, struct vm_area_struct, vm_rb);
294 if (vma->vm_start < prev)
295 printk("vm_start %lx prev %lx\n", vma->vm_start, prev), i = -1;
296 if (vma->vm_start < pend)
297 printk("vm_start %lx pend %lx\n", vma->vm_start, pend);
298 if (vma->vm_start > vma->vm_end)
299 printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start);
300 i++;
301 pn = nd;
David Millerd1af65d2007-02-28 20:13:13 -0800302 prev = vma->vm_start;
303 pend = vma->vm_end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 }
305 j = 0;
306 for (nd = pn; nd; nd = rb_prev(nd)) {
307 j++;
308 }
309 if (i != j)
310 printk("backwards %d, forwards %d\n", j, i), i = 0;
311 return i;
312}
313
314void validate_mm(struct mm_struct *mm)
315{
316 int bug = 0;
317 int i = 0;
318 struct vm_area_struct *tmp = mm->mmap;
319 while (tmp) {
320 tmp = tmp->vm_next;
321 i++;
322 }
323 if (i != mm->map_count)
324 printk("map_count %d vm_next %d\n", mm->map_count, i), bug = 1;
325 i = browse_rb(&mm->mm_rb);
326 if (i != mm->map_count)
327 printk("map_count %d rb %d\n", mm->map_count, i), bug = 1;
Eric Sesterhenn46a350e2006-04-01 01:23:29 +0200328 BUG_ON(bug);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329}
330#else
331#define validate_mm(mm) do { } while (0)
332#endif
333
334static struct vm_area_struct *
335find_vma_prepare(struct mm_struct *mm, unsigned long addr,
336 struct vm_area_struct **pprev, struct rb_node ***rb_link,
337 struct rb_node ** rb_parent)
338{
339 struct vm_area_struct * vma;
340 struct rb_node ** __rb_link, * __rb_parent, * rb_prev;
341
342 __rb_link = &mm->mm_rb.rb_node;
343 rb_prev = __rb_parent = NULL;
344 vma = NULL;
345
346 while (*__rb_link) {
347 struct vm_area_struct *vma_tmp;
348
349 __rb_parent = *__rb_link;
350 vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb);
351
352 if (vma_tmp->vm_end > addr) {
353 vma = vma_tmp;
354 if (vma_tmp->vm_start <= addr)
355 return vma;
356 __rb_link = &__rb_parent->rb_left;
357 } else {
358 rb_prev = __rb_parent;
359 __rb_link = &__rb_parent->rb_right;
360 }
361 }
362
363 *pprev = NULL;
364 if (rb_prev)
365 *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
366 *rb_link = __rb_link;
367 *rb_parent = __rb_parent;
368 return vma;
369}
370
371static inline void
372__vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
373 struct vm_area_struct *prev, struct rb_node *rb_parent)
374{
375 if (prev) {
376 vma->vm_next = prev->vm_next;
377 prev->vm_next = vma;
378 } else {
379 mm->mmap = vma;
380 if (rb_parent)
381 vma->vm_next = rb_entry(rb_parent,
382 struct vm_area_struct, vm_rb);
383 else
384 vma->vm_next = NULL;
385 }
386}
387
388void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma,
389 struct rb_node **rb_link, struct rb_node *rb_parent)
390{
391 rb_link_node(&vma->vm_rb, rb_parent, rb_link);
392 rb_insert_color(&vma->vm_rb, &mm->mm_rb);
393}
394
395static inline void __vma_link_file(struct vm_area_struct *vma)
396{
397 struct file * file;
398
399 file = vma->vm_file;
400 if (file) {
401 struct address_space *mapping = file->f_mapping;
402
403 if (vma->vm_flags & VM_DENYWRITE)
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800404 atomic_dec(&file->f_path.dentry->d_inode->i_writecount);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405 if (vma->vm_flags & VM_SHARED)
406 mapping->i_mmap_writable++;
407
408 flush_dcache_mmap_lock(mapping);
409 if (unlikely(vma->vm_flags & VM_NONLINEAR))
410 vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear);
411 else
412 vma_prio_tree_insert(vma, &mapping->i_mmap);
413 flush_dcache_mmap_unlock(mapping);
414 }
415}
416
417static void
418__vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
419 struct vm_area_struct *prev, struct rb_node **rb_link,
420 struct rb_node *rb_parent)
421{
422 __vma_link_list(mm, vma, prev, rb_parent);
423 __vma_link_rb(mm, vma, rb_link, rb_parent);
424 __anon_vma_link(vma);
425}
426
427static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
428 struct vm_area_struct *prev, struct rb_node **rb_link,
429 struct rb_node *rb_parent)
430{
431 struct address_space *mapping = NULL;
432
433 if (vma->vm_file)
434 mapping = vma->vm_file->f_mapping;
435
436 if (mapping) {
437 spin_lock(&mapping->i_mmap_lock);
438 vma->vm_truncate_count = mapping->truncate_count;
439 }
440 anon_vma_lock(vma);
441
442 __vma_link(mm, vma, prev, rb_link, rb_parent);
443 __vma_link_file(vma);
444
445 anon_vma_unlock(vma);
446 if (mapping)
447 spin_unlock(&mapping->i_mmap_lock);
448
449 mm->map_count++;
450 validate_mm(mm);
451}
452
453/*
454 * Helper for vma_adjust in the split_vma insert case:
455 * insert vm structure into list and rbtree and anon_vma,
456 * but it has already been inserted into prio_tree earlier.
457 */
458static void
459__insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma)
460{
461 struct vm_area_struct * __vma, * prev;
462 struct rb_node ** rb_link, * rb_parent;
463
464 __vma = find_vma_prepare(mm, vma->vm_start,&prev, &rb_link, &rb_parent);
Eric Sesterhenn46a350e2006-04-01 01:23:29 +0200465 BUG_ON(__vma && __vma->vm_start < vma->vm_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466 __vma_link(mm, vma, prev, rb_link, rb_parent);
467 mm->map_count++;
468}
469
470static inline void
471__vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma,
472 struct vm_area_struct *prev)
473{
474 prev->vm_next = vma->vm_next;
475 rb_erase(&vma->vm_rb, &mm->mm_rb);
476 if (mm->mmap_cache == vma)
477 mm->mmap_cache = prev;
478}
479
480/*
481 * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that
482 * is already present in an i_mmap tree without adjusting the tree.
483 * The following helper function should be used when such adjustments
484 * are necessary. The "insert" vma (if any) is to be inserted
485 * before we drop the necessary locks.
486 */
487void vma_adjust(struct vm_area_struct *vma, unsigned long start,
488 unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert)
489{
490 struct mm_struct *mm = vma->vm_mm;
491 struct vm_area_struct *next = vma->vm_next;
492 struct vm_area_struct *importer = NULL;
493 struct address_space *mapping = NULL;
494 struct prio_tree_root *root = NULL;
495 struct file *file = vma->vm_file;
496 struct anon_vma *anon_vma = NULL;
497 long adjust_next = 0;
498 int remove_next = 0;
499
500 if (next && !insert) {
501 if (end >= next->vm_end) {
502 /*
503 * vma expands, overlapping all the next, and
504 * perhaps the one after too (mprotect case 6).
505 */
506again: remove_next = 1 + (end > next->vm_end);
507 end = next->vm_end;
508 anon_vma = next->anon_vma;
509 importer = vma;
510 } else if (end > next->vm_start) {
511 /*
512 * vma expands, overlapping part of the next:
513 * mprotect case 5 shifting the boundary up.
514 */
515 adjust_next = (end - next->vm_start) >> PAGE_SHIFT;
516 anon_vma = next->anon_vma;
517 importer = vma;
518 } else if (end < vma->vm_end) {
519 /*
520 * vma shrinks, and !insert tells it's not
521 * split_vma inserting another: so it must be
522 * mprotect case 4 shifting the boundary down.
523 */
524 adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT);
525 anon_vma = next->anon_vma;
526 importer = next;
527 }
528 }
529
530 if (file) {
531 mapping = file->f_mapping;
532 if (!(vma->vm_flags & VM_NONLINEAR))
533 root = &mapping->i_mmap;
534 spin_lock(&mapping->i_mmap_lock);
535 if (importer &&
536 vma->vm_truncate_count != next->vm_truncate_count) {
537 /*
538 * unmap_mapping_range might be in progress:
539 * ensure that the expanding vma is rescanned.
540 */
541 importer->vm_truncate_count = 0;
542 }
543 if (insert) {
544 insert->vm_truncate_count = vma->vm_truncate_count;
545 /*
546 * Put into prio_tree now, so instantiated pages
547 * are visible to arm/parisc __flush_dcache_page
548 * throughout; but we cannot insert into address
549 * space until vma start or end is updated.
550 */
551 __vma_link_file(insert);
552 }
553 }
554
555 /*
556 * When changing only vma->vm_end, we don't really need
557 * anon_vma lock: but is that case worth optimizing out?
558 */
559 if (vma->anon_vma)
560 anon_vma = vma->anon_vma;
561 if (anon_vma) {
562 spin_lock(&anon_vma->lock);
563 /*
564 * Easily overlooked: when mprotect shifts the boundary,
565 * make sure the expanding vma has anon_vma set if the
566 * shrinking vma had, to cover any anon pages imported.
567 */
568 if (importer && !importer->anon_vma) {
569 importer->anon_vma = anon_vma;
570 __anon_vma_link(importer);
571 }
572 }
573
574 if (root) {
575 flush_dcache_mmap_lock(mapping);
576 vma_prio_tree_remove(vma, root);
577 if (adjust_next)
578 vma_prio_tree_remove(next, root);
579 }
580
581 vma->vm_start = start;
582 vma->vm_end = end;
583 vma->vm_pgoff = pgoff;
584 if (adjust_next) {
585 next->vm_start += adjust_next << PAGE_SHIFT;
586 next->vm_pgoff += adjust_next;
587 }
588
589 if (root) {
590 if (adjust_next)
591 vma_prio_tree_insert(next, root);
592 vma_prio_tree_insert(vma, root);
593 flush_dcache_mmap_unlock(mapping);
594 }
595
596 if (remove_next) {
597 /*
598 * vma_merge has merged next into vma, and needs
599 * us to remove next before dropping the locks.
600 */
601 __vma_unlink(mm, next, vma);
602 if (file)
603 __remove_shared_vm_struct(next, file, mapping);
604 if (next->anon_vma)
605 __anon_vma_merge(vma, next);
606 } else if (insert) {
607 /*
608 * split_vma has split insert from vma, and needs
609 * us to insert it before dropping the locks
610 * (it may either follow vma or precede it).
611 */
612 __insert_vm_struct(mm, insert);
613 }
614
615 if (anon_vma)
616 spin_unlock(&anon_vma->lock);
617 if (mapping)
618 spin_unlock(&mapping->i_mmap_lock);
619
620 if (remove_next) {
621 if (file)
622 fput(file);
623 mm->map_count--;
624 mpol_free(vma_policy(next));
625 kmem_cache_free(vm_area_cachep, next);
626 /*
627 * In mprotect's case 6 (see comments on vma_merge),
628 * we must remove another next too. It would clutter
629 * up the code too much to do both in one go.
630 */
631 if (remove_next == 2) {
632 next = vma->vm_next;
633 goto again;
634 }
635 }
636
637 validate_mm(mm);
638}
639
640/*
641 * If the vma has a ->close operation then the driver probably needs to release
642 * per-vma resources, so we don't attempt to merge those.
643 */
Hugh Dickinsa6f563d2006-03-22 00:08:29 -0800644#define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_RESERVED | VM_PFNMAP)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700645
646static inline int is_mergeable_vma(struct vm_area_struct *vma,
647 struct file *file, unsigned long vm_flags)
648{
649 if (vma->vm_flags != vm_flags)
650 return 0;
651 if (vma->vm_file != file)
652 return 0;
653 if (vma->vm_ops && vma->vm_ops->close)
654 return 0;
655 return 1;
656}
657
658static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1,
659 struct anon_vma *anon_vma2)
660{
661 return !anon_vma1 || !anon_vma2 || (anon_vma1 == anon_vma2);
662}
663
664/*
665 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
666 * in front of (at a lower virtual address and file offset than) the vma.
667 *
668 * We cannot merge two vmas if they have differently assigned (non-NULL)
669 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
670 *
671 * We don't check here for the merged mmap wrapping around the end of pagecache
672 * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which
673 * wrap, nor mmaps which cover the final page at index -1UL.
674 */
675static int
676can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags,
677 struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
678{
679 if (is_mergeable_vma(vma, file, vm_flags) &&
680 is_mergeable_anon_vma(anon_vma, vma->anon_vma)) {
681 if (vma->vm_pgoff == vm_pgoff)
682 return 1;
683 }
684 return 0;
685}
686
687/*
688 * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
689 * beyond (at a higher virtual address and file offset than) the vma.
690 *
691 * We cannot merge two vmas if they have differently assigned (non-NULL)
692 * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
693 */
694static int
695can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
696 struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
697{
698 if (is_mergeable_vma(vma, file, vm_flags) &&
699 is_mergeable_anon_vma(anon_vma, vma->anon_vma)) {
700 pgoff_t vm_pglen;
701 vm_pglen = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
702 if (vma->vm_pgoff + vm_pglen == vm_pgoff)
703 return 1;
704 }
705 return 0;
706}
707
708/*
709 * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out
710 * whether that can be merged with its predecessor or its successor.
711 * Or both (it neatly fills a hole).
712 *
713 * In most cases - when called for mmap, brk or mremap - [addr,end) is
714 * certain not to be mapped by the time vma_merge is called; but when
715 * called for mprotect, it is certain to be already mapped (either at
716 * an offset within prev, or at the start of next), and the flags of
717 * this area are about to be changed to vm_flags - and the no-change
718 * case has already been eliminated.
719 *
720 * The following mprotect cases have to be considered, where AAAA is
721 * the area passed down from mprotect_fixup, never extending beyond one
722 * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after:
723 *
724 * AAAA AAAA AAAA AAAA
725 * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX
726 * cannot merge might become might become might become
727 * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or
728 * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or
729 * mremap move: PPPPNNNNNNNN 8
730 * AAAA
731 * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN
732 * might become case 1 below case 2 below case 3 below
733 *
734 * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX:
735 * mprotect_fixup updates vm_flags & vm_page_prot on successful return.
736 */
737struct vm_area_struct *vma_merge(struct mm_struct *mm,
738 struct vm_area_struct *prev, unsigned long addr,
739 unsigned long end, unsigned long vm_flags,
740 struct anon_vma *anon_vma, struct file *file,
741 pgoff_t pgoff, struct mempolicy *policy)
742{
743 pgoff_t pglen = (end - addr) >> PAGE_SHIFT;
744 struct vm_area_struct *area, *next;
745
746 /*
747 * We later require that vma->vm_flags == vm_flags,
748 * so this tests vma->vm_flags & VM_SPECIAL, too.
749 */
750 if (vm_flags & VM_SPECIAL)
751 return NULL;
752
753 if (prev)
754 next = prev->vm_next;
755 else
756 next = mm->mmap;
757 area = next;
758 if (next && next->vm_end == end) /* cases 6, 7, 8 */
759 next = next->vm_next;
760
761 /*
762 * Can it merge with the predecessor?
763 */
764 if (prev && prev->vm_end == addr &&
765 mpol_equal(vma_policy(prev), policy) &&
766 can_vma_merge_after(prev, vm_flags,
767 anon_vma, file, pgoff)) {
768 /*
769 * OK, it can. Can we now merge in the successor as well?
770 */
771 if (next && end == next->vm_start &&
772 mpol_equal(policy, vma_policy(next)) &&
773 can_vma_merge_before(next, vm_flags,
774 anon_vma, file, pgoff+pglen) &&
775 is_mergeable_anon_vma(prev->anon_vma,
776 next->anon_vma)) {
777 /* cases 1, 6 */
778 vma_adjust(prev, prev->vm_start,
779 next->vm_end, prev->vm_pgoff, NULL);
780 } else /* cases 2, 5, 7 */
781 vma_adjust(prev, prev->vm_start,
782 end, prev->vm_pgoff, NULL);
783 return prev;
784 }
785
786 /*
787 * Can this new request be merged in front of next?
788 */
789 if (next && end == next->vm_start &&
790 mpol_equal(policy, vma_policy(next)) &&
791 can_vma_merge_before(next, vm_flags,
792 anon_vma, file, pgoff+pglen)) {
793 if (prev && addr < prev->vm_end) /* case 4 */
794 vma_adjust(prev, prev->vm_start,
795 addr, prev->vm_pgoff, NULL);
796 else /* cases 3, 8 */
797 vma_adjust(area, addr, next->vm_end,
798 next->vm_pgoff - pglen, NULL);
799 return area;
800 }
801
802 return NULL;
803}
804
805/*
806 * find_mergeable_anon_vma is used by anon_vma_prepare, to check
807 * neighbouring vmas for a suitable anon_vma, before it goes off
808 * to allocate a new anon_vma. It checks because a repetitive
809 * sequence of mprotects and faults may otherwise lead to distinct
810 * anon_vmas being allocated, preventing vma merge in subsequent
811 * mprotect.
812 */
813struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma)
814{
815 struct vm_area_struct *near;
816 unsigned long vm_flags;
817
818 near = vma->vm_next;
819 if (!near)
820 goto try_prev;
821
822 /*
823 * Since only mprotect tries to remerge vmas, match flags
824 * which might be mprotected into each other later on.
825 * Neither mlock nor madvise tries to remerge at present,
826 * so leave their flags as obstructing a merge.
827 */
828 vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC);
829 vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC);
830
831 if (near->anon_vma && vma->vm_end == near->vm_start &&
832 mpol_equal(vma_policy(vma), vma_policy(near)) &&
833 can_vma_merge_before(near, vm_flags,
834 NULL, vma->vm_file, vma->vm_pgoff +
835 ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT)))
836 return near->anon_vma;
837try_prev:
838 /*
839 * It is potentially slow to have to call find_vma_prev here.
840 * But it's only on the first write fault on the vma, not
841 * every time, and we could devise a way to avoid it later
842 * (e.g. stash info in next's anon_vma_node when assigning
843 * an anon_vma, or when trying vma_merge). Another time.
844 */
Eric Sesterhenn46a350e2006-04-01 01:23:29 +0200845 BUG_ON(find_vma_prev(vma->vm_mm, vma->vm_start, &near) != vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700846 if (!near)
847 goto none;
848
849 vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC);
850 vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC);
851
852 if (near->anon_vma && near->vm_end == vma->vm_start &&
853 mpol_equal(vma_policy(near), vma_policy(vma)) &&
854 can_vma_merge_after(near, vm_flags,
855 NULL, vma->vm_file, vma->vm_pgoff))
856 return near->anon_vma;
857none:
858 /*
859 * There's no absolute need to look only at touching neighbours:
860 * we could search further afield for "compatible" anon_vmas.
861 * But it would probably just be a waste of time searching,
862 * or lead to too many vmas hanging off the same anon_vma.
863 * We're trying to allow mprotect remerging later on,
864 * not trying to minimize memory used for anon_vmas.
865 */
866 return NULL;
867}
868
869#ifdef CONFIG_PROC_FS
Hugh Dickinsab50b8e2005-10-29 18:15:56 -0700870void vm_stat_account(struct mm_struct *mm, unsigned long flags,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700871 struct file *file, long pages)
872{
873 const unsigned long stack_flags
874 = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN);
875
Linus Torvalds1da177e2005-04-16 15:20:36 -0700876 if (file) {
877 mm->shared_vm += pages;
878 if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC)
879 mm->exec_vm += pages;
880 } else if (flags & stack_flags)
881 mm->stack_vm += pages;
882 if (flags & (VM_RESERVED|VM_IO))
883 mm->reserved_vm += pages;
884}
885#endif /* CONFIG_PROC_FS */
886
887/*
888 * The caller must hold down_write(current->mm->mmap_sem).
889 */
890
891unsigned long do_mmap_pgoff(struct file * file, unsigned long addr,
892 unsigned long len, unsigned long prot,
893 unsigned long flags, unsigned long pgoff)
894{
895 struct mm_struct * mm = current->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700896 struct inode *inode;
897 unsigned int vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700898 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700899 int accountable = 1;
Miklos Szeredi0165ab42007-07-15 23:38:26 -0700900 unsigned long reqprot = prot;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700901
Linus Torvalds1da177e2005-04-16 15:20:36 -0700902 /*
903 * Does the application expect PROT_READ to imply PROT_EXEC?
904 *
905 * (the exception is when the underlying filesystem is noexec
906 * mounted, in which case we dont add PROT_EXEC.)
907 */
908 if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800909 if (!(file && (file->f_path.mnt->mnt_flags & MNT_NOEXEC)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910 prot |= PROT_EXEC;
911
912 if (!len)
913 return -EINVAL;
914
Kirill Korotaev3a459752006-09-07 14:17:04 +0400915 error = arch_mmap_check(addr, len, flags);
916 if (error)
917 return error;
918
Linus Torvalds1da177e2005-04-16 15:20:36 -0700919 /* Careful about overflows.. */
920 len = PAGE_ALIGN(len);
921 if (!len || len > TASK_SIZE)
922 return -ENOMEM;
923
924 /* offset overflow? */
925 if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
926 return -EOVERFLOW;
927
928 /* Too many mappings? */
929 if (mm->map_count > sysctl_max_map_count)
930 return -ENOMEM;
931
932 /* Obtain the address to map to. we verify (or select) it and ensure
933 * that it represents a valid section of the address space.
934 */
935 addr = get_unmapped_area(file, addr, len, pgoff, flags);
936 if (addr & ~PAGE_MASK)
937 return addr;
938
939 /* Do simple checking here so the lower-level routines won't have
940 * to. we assume access permissions have been handled by the open
941 * of the memory object, so we don't do any here.
942 */
943 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) |
944 mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
945
946 if (flags & MAP_LOCKED) {
947 if (!can_do_mlock())
948 return -EPERM;
949 vm_flags |= VM_LOCKED;
950 }
951 /* mlock MCL_FUTURE? */
952 if (vm_flags & VM_LOCKED) {
953 unsigned long locked, lock_limit;
Chris Wright93ea1d02005-05-01 08:58:38 -0700954 locked = len >> PAGE_SHIFT;
955 locked += mm->locked_vm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700956 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
Chris Wright93ea1d02005-05-01 08:58:38 -0700957 lock_limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700958 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
959 return -EAGAIN;
960 }
961
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800962 inode = file ? file->f_path.dentry->d_inode : NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700963
964 if (file) {
965 switch (flags & MAP_TYPE) {
966 case MAP_SHARED:
967 if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE))
968 return -EACCES;
969
970 /*
971 * Make sure we don't allow writing to an append-only
972 * file..
973 */
974 if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE))
975 return -EACCES;
976
977 /*
978 * Make sure there are no mandatory locks on the file.
979 */
980 if (locks_verify_locked(inode))
981 return -EAGAIN;
982
983 vm_flags |= VM_SHARED | VM_MAYSHARE;
984 if (!(file->f_mode & FMODE_WRITE))
985 vm_flags &= ~(VM_MAYWRITE | VM_SHARED);
986
987 /* fall through */
988 case MAP_PRIVATE:
989 if (!(file->f_mode & FMODE_READ))
990 return -EACCES;
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800991 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
Linus Torvalds80c56062006-10-15 14:09:55 -0700992 if (vm_flags & VM_EXEC)
993 return -EPERM;
994 vm_flags &= ~VM_MAYEXEC;
995 }
996 if (is_file_hugepages(file))
997 accountable = 0;
998
999 if (!file->f_op || !file->f_op->mmap)
1000 return -ENODEV;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001001 break;
1002
1003 default:
1004 return -EINVAL;
1005 }
1006 } else {
1007 switch (flags & MAP_TYPE) {
1008 case MAP_SHARED:
1009 vm_flags |= VM_SHARED | VM_MAYSHARE;
1010 break;
1011 case MAP_PRIVATE:
1012 /*
1013 * Set pgoff according to addr for anon_vma.
1014 */
1015 pgoff = addr >> PAGE_SHIFT;
1016 break;
1017 default:
1018 return -EINVAL;
1019 }
1020 }
1021
Eric Parised032182007-06-28 15:55:21 -04001022 error = security_file_mmap(file, reqprot, prot, flags, addr, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001023 if (error)
1024 return error;
Eric Parised032182007-06-28 15:55:21 -04001025
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001026 return mmap_region(file, addr, len, flags, vm_flags, pgoff,
1027 accountable);
1028}
1029EXPORT_SYMBOL(do_mmap_pgoff);
1030
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001031/*
1032 * Some shared mappigns will want the pages marked read-only
1033 * to track write events. If so, we'll downgrade vm_page_prot
1034 * to the private version (using protection_map[] without the
1035 * VM_SHARED bit).
1036 */
1037int vma_wants_writenotify(struct vm_area_struct *vma)
1038{
1039 unsigned int vm_flags = vma->vm_flags;
1040
1041 /* If it was private or non-writable, the write bit is already clear */
1042 if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED)))
1043 return 0;
1044
1045 /* The backer wishes to know when pages are first written to? */
1046 if (vma->vm_ops && vma->vm_ops->page_mkwrite)
1047 return 1;
1048
1049 /* The open routine did something to the protections already? */
1050 if (pgprot_val(vma->vm_page_prot) !=
Coly Li3ed75eb2007-10-18 23:39:15 -07001051 pgprot_val(vm_get_page_prot(vm_flags)))
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001052 return 0;
1053
1054 /* Specialty mapping? */
1055 if (vm_flags & (VM_PFNMAP|VM_INSERTPAGE))
1056 return 0;
1057
1058 /* Can the mapping track the dirty pages? */
1059 return vma->vm_file && vma->vm_file->f_mapping &&
1060 mapping_cap_account_dirty(vma->vm_file->f_mapping);
1061}
1062
1063
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001064unsigned long mmap_region(struct file *file, unsigned long addr,
1065 unsigned long len, unsigned long flags,
1066 unsigned int vm_flags, unsigned long pgoff,
1067 int accountable)
1068{
1069 struct mm_struct *mm = current->mm;
1070 struct vm_area_struct *vma, *prev;
1071 int correct_wcount = 0;
1072 int error;
1073 struct rb_node **rb_link, *rb_parent;
1074 unsigned long charged = 0;
1075 struct inode *inode = file ? file->f_path.dentry->d_inode : NULL;
1076
Linus Torvalds1da177e2005-04-16 15:20:36 -07001077 /* Clear old maps */
1078 error = -ENOMEM;
1079munmap_back:
1080 vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
1081 if (vma && vma->vm_start < addr + len) {
1082 if (do_munmap(mm, addr, len))
1083 return -ENOMEM;
1084 goto munmap_back;
1085 }
1086
1087 /* Check against address space limit. */
akpm@osdl.org119f6572005-05-01 08:58:35 -07001088 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001089 return -ENOMEM;
1090
1091 if (accountable && (!(flags & MAP_NORESERVE) ||
1092 sysctl_overcommit_memory == OVERCOMMIT_NEVER)) {
1093 if (vm_flags & VM_SHARED) {
1094 /* Check memory availability in shmem_file_setup? */
1095 vm_flags |= VM_ACCOUNT;
1096 } else if (vm_flags & VM_WRITE) {
1097 /*
1098 * Private writable mapping: check memory availability
1099 */
1100 charged = len >> PAGE_SHIFT;
1101 if (security_vm_enough_memory(charged))
1102 return -ENOMEM;
1103 vm_flags |= VM_ACCOUNT;
1104 }
1105 }
1106
1107 /*
1108 * Can we just expand an old private anonymous mapping?
1109 * The VM_SHARED test is necessary because shmem_zero_setup
1110 * will create the file object for a shared anonymous map below.
1111 */
1112 if (!file && !(vm_flags & VM_SHARED) &&
1113 vma_merge(mm, prev, addr, addr + len, vm_flags,
1114 NULL, NULL, pgoff, NULL))
1115 goto out;
1116
1117 /*
1118 * Determine the object being mapped and call the appropriate
1119 * specific mapper. the address has already been validated, but
1120 * not unmapped, but the maps are removed from the list.
1121 */
Pekka Enbergc5e3b832006-03-25 03:06:43 -08001122 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001123 if (!vma) {
1124 error = -ENOMEM;
1125 goto unacct_error;
1126 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001127
1128 vma->vm_mm = mm;
1129 vma->vm_start = addr;
1130 vma->vm_end = addr + len;
1131 vma->vm_flags = vm_flags;
Coly Li3ed75eb2007-10-18 23:39:15 -07001132 vma->vm_page_prot = vm_get_page_prot(vm_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001133 vma->vm_pgoff = pgoff;
1134
1135 if (file) {
1136 error = -EINVAL;
1137 if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
1138 goto free_vma;
1139 if (vm_flags & VM_DENYWRITE) {
1140 error = deny_write_access(file);
1141 if (error)
1142 goto free_vma;
1143 correct_wcount = 1;
1144 }
1145 vma->vm_file = file;
1146 get_file(file);
1147 error = file->f_op->mmap(file, vma);
1148 if (error)
1149 goto unmap_and_free_vma;
1150 } else if (vm_flags & VM_SHARED) {
1151 error = shmem_zero_setup(vma);
1152 if (error)
1153 goto free_vma;
1154 }
1155
1156 /* We set VM_ACCOUNT in a shared mapping's vm_flags, to inform
1157 * shmem_zero_setup (perhaps called through /dev/zero's ->mmap)
1158 * that memory reservation must be checked; but that reservation
1159 * belongs to shared memory object, not to vma: so now clear it.
1160 */
1161 if ((vm_flags & (VM_SHARED|VM_ACCOUNT)) == (VM_SHARED|VM_ACCOUNT))
1162 vma->vm_flags &= ~VM_ACCOUNT;
1163
1164 /* Can addr have changed??
1165 *
1166 * Answer: Yes, several device drivers can do it in their
1167 * f_op->mmap method. -DaveM
1168 */
1169 addr = vma->vm_start;
1170 pgoff = vma->vm_pgoff;
1171 vm_flags = vma->vm_flags;
1172
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001173 if (vma_wants_writenotify(vma))
Hugh Dickins1ddd4392007-10-22 20:45:12 -07001174 vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED);
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001175
Linus Torvalds1da177e2005-04-16 15:20:36 -07001176 if (!file || !vma_merge(mm, prev, addr, vma->vm_end,
1177 vma->vm_flags, NULL, file, pgoff, vma_policy(vma))) {
1178 file = vma->vm_file;
1179 vma_link(mm, vma, prev, rb_link, rb_parent);
1180 if (correct_wcount)
1181 atomic_inc(&inode->i_writecount);
1182 } else {
1183 if (file) {
1184 if (correct_wcount)
1185 atomic_inc(&inode->i_writecount);
1186 fput(file);
1187 }
1188 mpol_free(vma_policy(vma));
1189 kmem_cache_free(vm_area_cachep, vma);
1190 }
1191out:
1192 mm->total_vm += len >> PAGE_SHIFT;
Hugh Dickinsab50b8e2005-10-29 18:15:56 -07001193 vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001194 if (vm_flags & VM_LOCKED) {
1195 mm->locked_vm += len >> PAGE_SHIFT;
1196 make_pages_present(addr, addr + len);
1197 }
Nick Piggin54cb8822007-07-19 01:46:59 -07001198 if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK))
1199 make_pages_present(addr, addr + len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001200 return addr;
1201
1202unmap_and_free_vma:
1203 if (correct_wcount)
1204 atomic_inc(&inode->i_writecount);
1205 vma->vm_file = NULL;
1206 fput(file);
1207
1208 /* Undo any partial mapping done by a device driver. */
Hugh Dickinse0da3822005-04-19 13:29:15 -07001209 unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end);
1210 charged = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001211free_vma:
1212 kmem_cache_free(vm_area_cachep, vma);
1213unacct_error:
1214 if (charged)
1215 vm_unacct_memory(charged);
1216 return error;
1217}
1218
Linus Torvalds1da177e2005-04-16 15:20:36 -07001219/* Get an address range which is currently unmapped.
1220 * For shmat() with addr=0.
1221 *
1222 * Ugly calling convention alert:
1223 * Return value with the low bits set means error value,
1224 * ie
1225 * if (ret & ~PAGE_MASK)
1226 * error = ret;
1227 *
1228 * This function "knows" that -ENOMEM has the bits set.
1229 */
1230#ifndef HAVE_ARCH_UNMAPPED_AREA
1231unsigned long
1232arch_get_unmapped_area(struct file *filp, unsigned long addr,
1233 unsigned long len, unsigned long pgoff, unsigned long flags)
1234{
1235 struct mm_struct *mm = current->mm;
1236 struct vm_area_struct *vma;
1237 unsigned long start_addr;
1238
1239 if (len > TASK_SIZE)
1240 return -ENOMEM;
1241
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001242 if (flags & MAP_FIXED)
1243 return addr;
1244
Linus Torvalds1da177e2005-04-16 15:20:36 -07001245 if (addr) {
1246 addr = PAGE_ALIGN(addr);
1247 vma = find_vma(mm, addr);
1248 if (TASK_SIZE - len >= addr &&
1249 (!vma || addr + len <= vma->vm_start))
1250 return addr;
1251 }
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001252 if (len > mm->cached_hole_size) {
1253 start_addr = addr = mm->free_area_cache;
1254 } else {
1255 start_addr = addr = TASK_UNMAPPED_BASE;
1256 mm->cached_hole_size = 0;
1257 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001258
1259full_search:
1260 for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
1261 /* At this point: (!vma || addr < vma->vm_end). */
1262 if (TASK_SIZE - len < addr) {
1263 /*
1264 * Start a new search - just in case we missed
1265 * some holes.
1266 */
1267 if (start_addr != TASK_UNMAPPED_BASE) {
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001268 addr = TASK_UNMAPPED_BASE;
1269 start_addr = addr;
1270 mm->cached_hole_size = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001271 goto full_search;
1272 }
1273 return -ENOMEM;
1274 }
1275 if (!vma || addr + len <= vma->vm_start) {
1276 /*
1277 * Remember the place where we stopped the search:
1278 */
1279 mm->free_area_cache = addr + len;
1280 return addr;
1281 }
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001282 if (addr + mm->cached_hole_size < vma->vm_start)
1283 mm->cached_hole_size = vma->vm_start - addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001284 addr = vma->vm_end;
1285 }
1286}
1287#endif
1288
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001289void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001290{
1291 /*
1292 * Is this a new hole at the lowest possible address?
1293 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001294 if (addr >= TASK_UNMAPPED_BASE && addr < mm->free_area_cache) {
1295 mm->free_area_cache = addr;
1296 mm->cached_hole_size = ~0UL;
1297 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001298}
1299
1300/*
1301 * This mmap-allocator allocates new areas top-down from below the
1302 * stack's low limit (the base):
1303 */
1304#ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
1305unsigned long
1306arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
1307 const unsigned long len, const unsigned long pgoff,
1308 const unsigned long flags)
1309{
1310 struct vm_area_struct *vma;
1311 struct mm_struct *mm = current->mm;
1312 unsigned long addr = addr0;
1313
1314 /* requested length too big for entire address space */
1315 if (len > TASK_SIZE)
1316 return -ENOMEM;
1317
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001318 if (flags & MAP_FIXED)
1319 return addr;
1320
Linus Torvalds1da177e2005-04-16 15:20:36 -07001321 /* requesting a specific address */
1322 if (addr) {
1323 addr = PAGE_ALIGN(addr);
1324 vma = find_vma(mm, addr);
1325 if (TASK_SIZE - len >= addr &&
1326 (!vma || addr + len <= vma->vm_start))
1327 return addr;
1328 }
1329
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001330 /* check if free_area_cache is useful for us */
1331 if (len <= mm->cached_hole_size) {
1332 mm->cached_hole_size = 0;
1333 mm->free_area_cache = mm->mmap_base;
1334 }
1335
Linus Torvalds1da177e2005-04-16 15:20:36 -07001336 /* either no address requested or can't fit in requested address hole */
1337 addr = mm->free_area_cache;
1338
1339 /* make sure it can fit in the remaining address space */
Linus Torvalds49a43872005-05-18 15:39:33 -07001340 if (addr > len) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001341 vma = find_vma(mm, addr-len);
1342 if (!vma || addr <= vma->vm_start)
1343 /* remember the address as a hint for next time */
1344 return (mm->free_area_cache = addr-len);
1345 }
1346
Chris Wright73219d12005-06-21 17:14:52 -07001347 if (mm->mmap_base < len)
1348 goto bottomup;
1349
Linus Torvalds1da177e2005-04-16 15:20:36 -07001350 addr = mm->mmap_base-len;
1351
1352 do {
1353 /*
1354 * Lookup failure means no vma is above this address,
1355 * else if new region fits below vma->vm_start,
1356 * return with success:
1357 */
1358 vma = find_vma(mm, addr);
1359 if (!vma || addr+len <= vma->vm_start)
1360 /* remember the address as a hint for next time */
1361 return (mm->free_area_cache = addr);
1362
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001363 /* remember the largest hole we saw so far */
1364 if (addr + mm->cached_hole_size < vma->vm_start)
1365 mm->cached_hole_size = vma->vm_start - addr;
1366
Linus Torvalds1da177e2005-04-16 15:20:36 -07001367 /* try just below the current vma->vm_start */
1368 addr = vma->vm_start-len;
Linus Torvalds49a43872005-05-18 15:39:33 -07001369 } while (len < vma->vm_start);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001370
Chris Wright73219d12005-06-21 17:14:52 -07001371bottomup:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001372 /*
1373 * A failed mmap() very likely causes application failure,
1374 * so fall back to the bottom-up function here. This scenario
1375 * can happen with large stack limits and large mmap()
1376 * allocations.
1377 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001378 mm->cached_hole_size = ~0UL;
1379 mm->free_area_cache = TASK_UNMAPPED_BASE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001380 addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
1381 /*
1382 * Restore the topdown base:
1383 */
1384 mm->free_area_cache = mm->mmap_base;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001385 mm->cached_hole_size = ~0UL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001386
1387 return addr;
1388}
1389#endif
1390
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001391void arch_unmap_area_topdown(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001392{
1393 /*
1394 * Is this a new hole at the highest possible address?
1395 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001396 if (addr > mm->free_area_cache)
1397 mm->free_area_cache = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001398
1399 /* dont allow allocations above current base */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001400 if (mm->free_area_cache > mm->mmap_base)
1401 mm->free_area_cache = mm->mmap_base;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001402}
1403
1404unsigned long
1405get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
1406 unsigned long pgoff, unsigned long flags)
1407{
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001408 unsigned long (*get_area)(struct file *, unsigned long,
1409 unsigned long, unsigned long, unsigned long);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001410
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001411 get_area = current->mm->get_unmapped_area;
1412 if (file && file->f_op && file->f_op->get_unmapped_area)
1413 get_area = file->f_op->get_unmapped_area;
1414 addr = get_area(file, addr, len, pgoff, flags);
1415 if (IS_ERR_VALUE(addr))
1416 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001417
Linus Torvalds07ab67c2005-05-19 22:43:37 -07001418 if (addr > TASK_SIZE - len)
1419 return -ENOMEM;
1420 if (addr & ~PAGE_MASK)
1421 return -EINVAL;
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001422
Linus Torvalds07ab67c2005-05-19 22:43:37 -07001423 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001424}
1425
1426EXPORT_SYMBOL(get_unmapped_area);
1427
1428/* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
1429struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr)
1430{
1431 struct vm_area_struct *vma = NULL;
1432
1433 if (mm) {
1434 /* Check the cache first. */
1435 /* (Cache hit rate is typically around 35%.) */
1436 vma = mm->mmap_cache;
1437 if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) {
1438 struct rb_node * rb_node;
1439
1440 rb_node = mm->mm_rb.rb_node;
1441 vma = NULL;
1442
1443 while (rb_node) {
1444 struct vm_area_struct * vma_tmp;
1445
1446 vma_tmp = rb_entry(rb_node,
1447 struct vm_area_struct, vm_rb);
1448
1449 if (vma_tmp->vm_end > addr) {
1450 vma = vma_tmp;
1451 if (vma_tmp->vm_start <= addr)
1452 break;
1453 rb_node = rb_node->rb_left;
1454 } else
1455 rb_node = rb_node->rb_right;
1456 }
1457 if (vma)
1458 mm->mmap_cache = vma;
1459 }
1460 }
1461 return vma;
1462}
1463
1464EXPORT_SYMBOL(find_vma);
1465
1466/* Same as find_vma, but also return a pointer to the previous VMA in *pprev. */
1467struct vm_area_struct *
1468find_vma_prev(struct mm_struct *mm, unsigned long addr,
1469 struct vm_area_struct **pprev)
1470{
1471 struct vm_area_struct *vma = NULL, *prev = NULL;
1472 struct rb_node * rb_node;
1473 if (!mm)
1474 goto out;
1475
1476 /* Guard against addr being lower than the first VMA */
1477 vma = mm->mmap;
1478
1479 /* Go through the RB tree quickly. */
1480 rb_node = mm->mm_rb.rb_node;
1481
1482 while (rb_node) {
1483 struct vm_area_struct *vma_tmp;
1484 vma_tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb);
1485
1486 if (addr < vma_tmp->vm_end) {
1487 rb_node = rb_node->rb_left;
1488 } else {
1489 prev = vma_tmp;
1490 if (!prev->vm_next || (addr < prev->vm_next->vm_end))
1491 break;
1492 rb_node = rb_node->rb_right;
1493 }
1494 }
1495
1496out:
1497 *pprev = prev;
1498 return prev ? prev->vm_next : vma;
1499}
1500
1501/*
1502 * Verify that the stack growth is acceptable and
1503 * update accounting. This is shared with both the
1504 * grow-up and grow-down cases.
1505 */
1506static int acct_stack_growth(struct vm_area_struct * vma, unsigned long size, unsigned long grow)
1507{
1508 struct mm_struct *mm = vma->vm_mm;
1509 struct rlimit *rlim = current->signal->rlim;
Adam Litke0d59a012007-01-30 14:35:39 -08001510 unsigned long new_start;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001511
1512 /* address space limit tests */
akpm@osdl.org119f6572005-05-01 08:58:35 -07001513 if (!may_expand_vm(mm, grow))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001514 return -ENOMEM;
1515
1516 /* Stack limit test */
1517 if (size > rlim[RLIMIT_STACK].rlim_cur)
1518 return -ENOMEM;
1519
1520 /* mlock limit tests */
1521 if (vma->vm_flags & VM_LOCKED) {
1522 unsigned long locked;
1523 unsigned long limit;
1524 locked = mm->locked_vm + grow;
1525 limit = rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT;
1526 if (locked > limit && !capable(CAP_IPC_LOCK))
1527 return -ENOMEM;
1528 }
1529
Adam Litke0d59a012007-01-30 14:35:39 -08001530 /* Check to ensure the stack will not grow into a hugetlb-only region */
1531 new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start :
1532 vma->vm_end - size;
1533 if (is_hugepage_only_range(vma->vm_mm, new_start, size))
1534 return -EFAULT;
1535
Linus Torvalds1da177e2005-04-16 15:20:36 -07001536 /*
1537 * Overcommit.. This must be the final test, as it will
1538 * update security statistics.
1539 */
1540 if (security_vm_enough_memory(grow))
1541 return -ENOMEM;
1542
1543 /* Ok, everything looks good - let it rip */
1544 mm->total_vm += grow;
1545 if (vma->vm_flags & VM_LOCKED)
1546 mm->locked_vm += grow;
Hugh Dickinsab50b8e2005-10-29 18:15:56 -07001547 vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001548 return 0;
1549}
1550
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001551#if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001552/*
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001553 * PA-RISC uses this for its stack; IA64 for its Register Backing Store.
1554 * vma is the last one with address > vma->vm_end. Have to extend vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001555 */
Matthew Wilcox9ab88512005-11-18 16:16:42 -05001556#ifndef CONFIG_IA64
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001557static inline
1558#endif
1559int expand_upwards(struct vm_area_struct *vma, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001560{
1561 int error;
1562
1563 if (!(vma->vm_flags & VM_GROWSUP))
1564 return -EFAULT;
1565
1566 /*
1567 * We must make sure the anon_vma is allocated
1568 * so that the anon_vma locking is not a noop.
1569 */
1570 if (unlikely(anon_vma_prepare(vma)))
1571 return -ENOMEM;
1572 anon_vma_lock(vma);
1573
1574 /*
1575 * vma->vm_start/vm_end cannot change under us because the caller
1576 * is required to hold the mmap_sem in read mode. We need the
1577 * anon_vma lock to serialize against concurrent expand_stacks.
Helge Deller06b32f32006-12-19 19:28:33 +01001578 * Also guard against wrapping around to address 0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001579 */
Helge Deller06b32f32006-12-19 19:28:33 +01001580 if (address < PAGE_ALIGN(address+4))
1581 address = PAGE_ALIGN(address+4);
1582 else {
1583 anon_vma_unlock(vma);
1584 return -ENOMEM;
1585 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001586 error = 0;
1587
1588 /* Somebody else might have raced and expanded it already */
1589 if (address > vma->vm_end) {
1590 unsigned long size, grow;
1591
1592 size = address - vma->vm_start;
1593 grow = (address - vma->vm_end) >> PAGE_SHIFT;
1594
1595 error = acct_stack_growth(vma, size, grow);
1596 if (!error)
1597 vma->vm_end = address;
1598 }
1599 anon_vma_unlock(vma);
1600 return error;
1601}
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001602#endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
1603
Linus Torvalds1da177e2005-04-16 15:20:36 -07001604/*
1605 * vma is the first one with address < vma->vm_start. Have to extend vma.
1606 */
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001607static inline int expand_downwards(struct vm_area_struct *vma,
1608 unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001609{
1610 int error;
1611
1612 /*
1613 * We must make sure the anon_vma is allocated
1614 * so that the anon_vma locking is not a noop.
1615 */
1616 if (unlikely(anon_vma_prepare(vma)))
1617 return -ENOMEM;
1618 anon_vma_lock(vma);
1619
1620 /*
1621 * vma->vm_start/vm_end cannot change under us because the caller
1622 * is required to hold the mmap_sem in read mode. We need the
1623 * anon_vma lock to serialize against concurrent expand_stacks.
1624 */
1625 address &= PAGE_MASK;
1626 error = 0;
1627
1628 /* Somebody else might have raced and expanded it already */
1629 if (address < vma->vm_start) {
1630 unsigned long size, grow;
1631
1632 size = vma->vm_end - address;
1633 grow = (vma->vm_start - address) >> PAGE_SHIFT;
1634
1635 error = acct_stack_growth(vma, size, grow);
1636 if (!error) {
1637 vma->vm_start = address;
1638 vma->vm_pgoff -= grow;
1639 }
1640 }
1641 anon_vma_unlock(vma);
1642 return error;
1643}
1644
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001645int expand_stack_downwards(struct vm_area_struct *vma, unsigned long address)
1646{
1647 return expand_downwards(vma, address);
1648}
1649
1650#ifdef CONFIG_STACK_GROWSUP
1651int expand_stack(struct vm_area_struct *vma, unsigned long address)
1652{
1653 return expand_upwards(vma, address);
1654}
1655
1656struct vm_area_struct *
1657find_extend_vma(struct mm_struct *mm, unsigned long addr)
1658{
1659 struct vm_area_struct *vma, *prev;
1660
1661 addr &= PAGE_MASK;
1662 vma = find_vma_prev(mm, addr, &prev);
1663 if (vma && (vma->vm_start <= addr))
1664 return vma;
1665 if (!prev || expand_stack(prev, addr))
1666 return NULL;
1667 if (prev->vm_flags & VM_LOCKED)
1668 make_pages_present(addr, prev->vm_end);
1669 return prev;
1670}
1671#else
1672int expand_stack(struct vm_area_struct *vma, unsigned long address)
1673{
1674 return expand_downwards(vma, address);
1675}
1676
Linus Torvalds1da177e2005-04-16 15:20:36 -07001677struct vm_area_struct *
1678find_extend_vma(struct mm_struct * mm, unsigned long addr)
1679{
1680 struct vm_area_struct * vma;
1681 unsigned long start;
1682
1683 addr &= PAGE_MASK;
1684 vma = find_vma(mm,addr);
1685 if (!vma)
1686 return NULL;
1687 if (vma->vm_start <= addr)
1688 return vma;
1689 if (!(vma->vm_flags & VM_GROWSDOWN))
1690 return NULL;
1691 start = vma->vm_start;
1692 if (expand_stack(vma, addr))
1693 return NULL;
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001694 if (vma->vm_flags & VM_LOCKED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001695 make_pages_present(addr, start);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001696 return vma;
1697}
1698#endif
1699
Linus Torvalds1da177e2005-04-16 15:20:36 -07001700/*
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001701 * Ok - we have the memory areas we should free on the vma list,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001702 * so release them, and do the vma updates.
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001703 *
1704 * Called with the mm semaphore held.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001705 */
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001706static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001707{
Hugh Dickins365e9c872005-10-29 18:16:18 -07001708 /* Update high watermark before we lower total_vm */
1709 update_hiwater_vm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001710 do {
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001711 long nrpages = vma_pages(vma);
1712
1713 mm->total_vm -= nrpages;
1714 if (vma->vm_flags & VM_LOCKED)
1715 mm->locked_vm -= nrpages;
1716 vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -07001717 vma = remove_vma(vma);
Hugh Dickins146425a2005-04-19 13:29:18 -07001718 } while (vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001719 validate_mm(mm);
1720}
1721
1722/*
1723 * Get rid of page table information in the indicated region.
1724 *
Paolo 'Blaisorblade' Giarrussof10df682005-09-21 09:55:37 -07001725 * Called with the mm semaphore held.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001726 */
1727static void unmap_region(struct mm_struct *mm,
Hugh Dickinse0da3822005-04-19 13:29:15 -07001728 struct vm_area_struct *vma, struct vm_area_struct *prev,
1729 unsigned long start, unsigned long end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001730{
Hugh Dickinse0da3822005-04-19 13:29:15 -07001731 struct vm_area_struct *next = prev? prev->vm_next: mm->mmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001732 struct mmu_gather *tlb;
1733 unsigned long nr_accounted = 0;
1734
1735 lru_add_drain();
1736 tlb = tlb_gather_mmu(mm, 0);
Hugh Dickins365e9c872005-10-29 18:16:18 -07001737 update_hiwater_rss(mm);
Hugh Dickins508034a2005-10-29 18:16:30 -07001738 unmap_vmas(&tlb, vma, start, end, &nr_accounted, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001739 vm_unacct_memory(nr_accounted);
Hugh Dickinse2cdef82005-04-19 13:29:19 -07001740 free_pgtables(&tlb, vma, prev? prev->vm_end: FIRST_USER_ADDRESS,
Hugh Dickinse0da3822005-04-19 13:29:15 -07001741 next? next->vm_start: 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001742 tlb_finish_mmu(tlb, start, end);
1743}
1744
1745/*
1746 * Create a list of vma's touched by the unmap, removing them from the mm's
1747 * vma list as we go..
1748 */
1749static void
1750detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
1751 struct vm_area_struct *prev, unsigned long end)
1752{
1753 struct vm_area_struct **insertion_point;
1754 struct vm_area_struct *tail_vma = NULL;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001755 unsigned long addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001756
1757 insertion_point = (prev ? &prev->vm_next : &mm->mmap);
1758 do {
1759 rb_erase(&vma->vm_rb, &mm->mm_rb);
1760 mm->map_count--;
1761 tail_vma = vma;
1762 vma = vma->vm_next;
1763 } while (vma && vma->vm_start < end);
1764 *insertion_point = vma;
1765 tail_vma->vm_next = NULL;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001766 if (mm->unmap_area == arch_unmap_area)
1767 addr = prev ? prev->vm_end : mm->mmap_base;
1768 else
1769 addr = vma ? vma->vm_start : mm->mmap_base;
1770 mm->unmap_area(mm, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001771 mm->mmap_cache = NULL; /* Kill the cache. */
1772}
1773
1774/*
1775 * Split a vma into two pieces at address 'addr', a new vma is allocated
Michael Opdenacker59c51592007-05-09 08:57:56 +02001776 * either for the first part or the tail.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001777 */
1778int split_vma(struct mm_struct * mm, struct vm_area_struct * vma,
1779 unsigned long addr, int new_below)
1780{
1781 struct mempolicy *pol;
1782 struct vm_area_struct *new;
1783
1784 if (is_vm_hugetlb_page(vma) && (addr & ~HPAGE_MASK))
1785 return -EINVAL;
1786
1787 if (mm->map_count >= sysctl_max_map_count)
1788 return -ENOMEM;
1789
Christoph Lametere94b1762006-12-06 20:33:17 -08001790 new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001791 if (!new)
1792 return -ENOMEM;
1793
1794 /* most fields are the same, copy all, and then fixup */
1795 *new = *vma;
1796
1797 if (new_below)
1798 new->vm_end = addr;
1799 else {
1800 new->vm_start = addr;
1801 new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT);
1802 }
1803
1804 pol = mpol_copy(vma_policy(vma));
1805 if (IS_ERR(pol)) {
1806 kmem_cache_free(vm_area_cachep, new);
1807 return PTR_ERR(pol);
1808 }
1809 vma_set_policy(new, pol);
1810
1811 if (new->vm_file)
1812 get_file(new->vm_file);
1813
1814 if (new->vm_ops && new->vm_ops->open)
1815 new->vm_ops->open(new);
1816
1817 if (new_below)
1818 vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff +
1819 ((addr - new->vm_start) >> PAGE_SHIFT), new);
1820 else
1821 vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new);
1822
1823 return 0;
1824}
1825
1826/* Munmap is split into 2 main parts -- this part which finds
1827 * what needs doing, and the areas themselves, which do the
1828 * work. This now handles partial unmappings.
1829 * Jeremy Fitzhardinge <jeremy@goop.org>
1830 */
1831int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
1832{
1833 unsigned long end;
Hugh Dickins146425a2005-04-19 13:29:18 -07001834 struct vm_area_struct *vma, *prev, *last;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001835
1836 if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start)
1837 return -EINVAL;
1838
1839 if ((len = PAGE_ALIGN(len)) == 0)
1840 return -EINVAL;
1841
1842 /* Find the first overlapping VMA */
Hugh Dickins146425a2005-04-19 13:29:18 -07001843 vma = find_vma_prev(mm, start, &prev);
1844 if (!vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001845 return 0;
Hugh Dickins146425a2005-04-19 13:29:18 -07001846 /* we have start < vma->vm_end */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001847
1848 /* if it doesn't overlap, we have nothing.. */
1849 end = start + len;
Hugh Dickins146425a2005-04-19 13:29:18 -07001850 if (vma->vm_start >= end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001851 return 0;
1852
1853 /*
1854 * If we need to split any vma, do it now to save pain later.
1855 *
1856 * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially
1857 * unmapped vm_area_struct will remain in use: so lower split_vma
1858 * places tmp vma above, and higher split_vma places tmp vma below.
1859 */
Hugh Dickins146425a2005-04-19 13:29:18 -07001860 if (start > vma->vm_start) {
1861 int error = split_vma(mm, vma, start, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001862 if (error)
1863 return error;
Hugh Dickins146425a2005-04-19 13:29:18 -07001864 prev = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001865 }
1866
1867 /* Does it split the last one? */
1868 last = find_vma(mm, end);
1869 if (last && end > last->vm_start) {
1870 int error = split_vma(mm, last, end, 1);
1871 if (error)
1872 return error;
1873 }
Hugh Dickins146425a2005-04-19 13:29:18 -07001874 vma = prev? prev->vm_next: mm->mmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001875
1876 /*
1877 * Remove the vma's, and unmap the actual pages
1878 */
Hugh Dickins146425a2005-04-19 13:29:18 -07001879 detach_vmas_to_be_unmapped(mm, vma, prev, end);
1880 unmap_region(mm, vma, prev, start, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001881
1882 /* Fix up all other VM information */
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001883 remove_vma_list(mm, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001884
1885 return 0;
1886}
1887
1888EXPORT_SYMBOL(do_munmap);
1889
1890asmlinkage long sys_munmap(unsigned long addr, size_t len)
1891{
1892 int ret;
1893 struct mm_struct *mm = current->mm;
1894
1895 profile_munmap(addr);
1896
1897 down_write(&mm->mmap_sem);
1898 ret = do_munmap(mm, addr, len);
1899 up_write(&mm->mmap_sem);
1900 return ret;
1901}
1902
1903static inline void verify_mm_writelocked(struct mm_struct *mm)
1904{
Paul E. McKenneya241ec62005-10-30 15:03:12 -08001905#ifdef CONFIG_DEBUG_VM
Linus Torvalds1da177e2005-04-16 15:20:36 -07001906 if (unlikely(down_read_trylock(&mm->mmap_sem))) {
1907 WARN_ON(1);
1908 up_read(&mm->mmap_sem);
1909 }
1910#endif
1911}
1912
1913/*
1914 * this is really a simplified "do_mmap". it only handles
1915 * anonymous maps. eventually we may be able to do some
1916 * brk-specific accounting here.
1917 */
1918unsigned long do_brk(unsigned long addr, unsigned long len)
1919{
1920 struct mm_struct * mm = current->mm;
1921 struct vm_area_struct * vma, * prev;
1922 unsigned long flags;
1923 struct rb_node ** rb_link, * rb_parent;
1924 pgoff_t pgoff = addr >> PAGE_SHIFT;
Kirill Korotaev3a459752006-09-07 14:17:04 +04001925 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001926
1927 len = PAGE_ALIGN(len);
1928 if (!len)
1929 return addr;
1930
1931 if ((addr + len) > TASK_SIZE || (addr + len) < addr)
1932 return -EINVAL;
1933
Hugh Dickinscd2579d2006-11-14 13:43:38 +00001934 if (is_hugepage_only_range(mm, addr, len))
1935 return -EINVAL;
David Gibsoncb07c9a2006-11-14 02:03:38 -08001936
Kirill Korotaev3a459752006-09-07 14:17:04 +04001937 flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags;
1938
1939 error = arch_mmap_check(addr, len, flags);
1940 if (error)
1941 return error;
1942
Linus Torvalds1da177e2005-04-16 15:20:36 -07001943 /*
1944 * mlock MCL_FUTURE?
1945 */
1946 if (mm->def_flags & VM_LOCKED) {
1947 unsigned long locked, lock_limit;
Chris Wright93ea1d02005-05-01 08:58:38 -07001948 locked = len >> PAGE_SHIFT;
1949 locked += mm->locked_vm;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001950 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
Chris Wright93ea1d02005-05-01 08:58:38 -07001951 lock_limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001952 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
1953 return -EAGAIN;
1954 }
1955
1956 /*
1957 * mm->mmap_sem is required to protect against another thread
1958 * changing the mappings in case we sleep.
1959 */
1960 verify_mm_writelocked(mm);
1961
1962 /*
1963 * Clear old maps. this also does some error checking for us
1964 */
1965 munmap_back:
1966 vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
1967 if (vma && vma->vm_start < addr + len) {
1968 if (do_munmap(mm, addr, len))
1969 return -ENOMEM;
1970 goto munmap_back;
1971 }
1972
1973 /* Check against address space limits *after* clearing old maps... */
akpm@osdl.org119f6572005-05-01 08:58:35 -07001974 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001975 return -ENOMEM;
1976
1977 if (mm->map_count > sysctl_max_map_count)
1978 return -ENOMEM;
1979
1980 if (security_vm_enough_memory(len >> PAGE_SHIFT))
1981 return -ENOMEM;
1982
Linus Torvalds1da177e2005-04-16 15:20:36 -07001983 /* Can we just expand an old private anonymous mapping? */
1984 if (vma_merge(mm, prev, addr, addr + len, flags,
1985 NULL, NULL, pgoff, NULL))
1986 goto out;
1987
1988 /*
1989 * create a vma struct for an anonymous mapping
1990 */
Pekka Enbergc5e3b832006-03-25 03:06:43 -08001991 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001992 if (!vma) {
1993 vm_unacct_memory(len >> PAGE_SHIFT);
1994 return -ENOMEM;
1995 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001996
1997 vma->vm_mm = mm;
1998 vma->vm_start = addr;
1999 vma->vm_end = addr + len;
2000 vma->vm_pgoff = pgoff;
2001 vma->vm_flags = flags;
Coly Li3ed75eb2007-10-18 23:39:15 -07002002 vma->vm_page_prot = vm_get_page_prot(flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002003 vma_link(mm, vma, prev, rb_link, rb_parent);
2004out:
2005 mm->total_vm += len >> PAGE_SHIFT;
2006 if (flags & VM_LOCKED) {
2007 mm->locked_vm += len >> PAGE_SHIFT;
2008 make_pages_present(addr, addr + len);
2009 }
2010 return addr;
2011}
2012
2013EXPORT_SYMBOL(do_brk);
2014
2015/* Release all mmaps. */
2016void exit_mmap(struct mm_struct *mm)
2017{
2018 struct mmu_gather *tlb;
Hugh Dickinse0da3822005-04-19 13:29:15 -07002019 struct vm_area_struct *vma = mm->mmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002020 unsigned long nr_accounted = 0;
Hugh Dickinsee39b372005-04-19 13:29:15 -07002021 unsigned long end;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002022
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +02002023 /* mm's last user has gone, and its about to be pulled down */
2024 arch_exit_mmap(mm);
2025
Linus Torvalds1da177e2005-04-16 15:20:36 -07002026 lru_add_drain();
Linus Torvalds1da177e2005-04-16 15:20:36 -07002027 flush_cache_mm(mm);
Hugh Dickinse0da3822005-04-19 13:29:15 -07002028 tlb = tlb_gather_mmu(mm, 1);
Hugh Dickins365e9c872005-10-29 18:16:18 -07002029 /* Don't update_hiwater_rss(mm) here, do_exit already did */
Hugh Dickinse0da3822005-04-19 13:29:15 -07002030 /* Use -1 here to ensure all VMAs in the mm are unmapped */
Hugh Dickins508034a2005-10-29 18:16:30 -07002031 end = unmap_vmas(&tlb, vma, 0, -1, &nr_accounted, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002032 vm_unacct_memory(nr_accounted);
Hugh Dickinse2cdef82005-04-19 13:29:19 -07002033 free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0);
Hugh Dickinsee39b372005-04-19 13:29:15 -07002034 tlb_finish_mmu(tlb, 0, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002035
Linus Torvalds1da177e2005-04-16 15:20:36 -07002036 /*
Hugh Dickins8f4f8c12005-10-29 18:16:29 -07002037 * Walk the list again, actually closing and freeing it,
2038 * with preemption enabled, without holding any MM locks.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002039 */
Hugh Dickinsa8fb5612005-10-29 18:15:57 -07002040 while (vma)
2041 vma = remove_vma(vma);
Hugh Dickinse0da3822005-04-19 13:29:15 -07002042
Hugh Dickinse2cdef82005-04-19 13:29:19 -07002043 BUG_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002044}
2045
2046/* Insert vm structure into process list sorted by address
2047 * and into the inode's i_mmap tree. If vm_file is non-NULL
2048 * then i_mmap_lock is taken here.
2049 */
2050int insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma)
2051{
2052 struct vm_area_struct * __vma, * prev;
2053 struct rb_node ** rb_link, * rb_parent;
2054
2055 /*
2056 * The vm_pgoff of a purely anonymous vma should be irrelevant
2057 * until its first write fault, when page's anon_vma and index
2058 * are set. But now set the vm_pgoff it will almost certainly
2059 * end up with (unless mremap moves it elsewhere before that
2060 * first wfault), so /proc/pid/maps tells a consistent story.
2061 *
2062 * By setting it to reflect the virtual start address of the
2063 * vma, merges and splits can happen in a seamless way, just
2064 * using the existing file pgoff checks and manipulations.
2065 * Similarly in do_mmap_pgoff and in do_brk.
2066 */
2067 if (!vma->vm_file) {
2068 BUG_ON(vma->anon_vma);
2069 vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT;
2070 }
2071 __vma = find_vma_prepare(mm,vma->vm_start,&prev,&rb_link,&rb_parent);
2072 if (__vma && __vma->vm_start < vma->vm_end)
2073 return -ENOMEM;
Hugh Dickins2fd4ef82005-09-14 06:13:02 +01002074 if ((vma->vm_flags & VM_ACCOUNT) &&
Alan Cox34b4e4a2007-08-22 14:01:28 -07002075 security_vm_enough_memory_mm(mm, vma_pages(vma)))
Hugh Dickins2fd4ef82005-09-14 06:13:02 +01002076 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002077 vma_link(mm, vma, prev, rb_link, rb_parent);
2078 return 0;
2079}
2080
2081/*
2082 * Copy the vma structure to a new location in the same mm,
2083 * prior to moving page table entries, to effect an mremap move.
2084 */
2085struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
2086 unsigned long addr, unsigned long len, pgoff_t pgoff)
2087{
2088 struct vm_area_struct *vma = *vmap;
2089 unsigned long vma_start = vma->vm_start;
2090 struct mm_struct *mm = vma->vm_mm;
2091 struct vm_area_struct *new_vma, *prev;
2092 struct rb_node **rb_link, *rb_parent;
2093 struct mempolicy *pol;
2094
2095 /*
2096 * If anonymous vma has not yet been faulted, update new pgoff
2097 * to match new location, to increase its chance of merging.
2098 */
2099 if (!vma->vm_file && !vma->anon_vma)
2100 pgoff = addr >> PAGE_SHIFT;
2101
2102 find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
2103 new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags,
2104 vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma));
2105 if (new_vma) {
2106 /*
2107 * Source vma may have been merged into new_vma
2108 */
2109 if (vma_start >= new_vma->vm_start &&
2110 vma_start < new_vma->vm_end)
2111 *vmap = new_vma;
2112 } else {
Christoph Lametere94b1762006-12-06 20:33:17 -08002113 new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002114 if (new_vma) {
2115 *new_vma = *vma;
2116 pol = mpol_copy(vma_policy(vma));
2117 if (IS_ERR(pol)) {
2118 kmem_cache_free(vm_area_cachep, new_vma);
2119 return NULL;
2120 }
2121 vma_set_policy(new_vma, pol);
2122 new_vma->vm_start = addr;
2123 new_vma->vm_end = addr + len;
2124 new_vma->vm_pgoff = pgoff;
2125 if (new_vma->vm_file)
2126 get_file(new_vma->vm_file);
2127 if (new_vma->vm_ops && new_vma->vm_ops->open)
2128 new_vma->vm_ops->open(new_vma);
2129 vma_link(mm, new_vma, prev, rb_link, rb_parent);
2130 }
2131 }
2132 return new_vma;
2133}
akpm@osdl.org119f6572005-05-01 08:58:35 -07002134
2135/*
2136 * Return true if the calling process may expand its vm space by the passed
2137 * number of pages
2138 */
2139int may_expand_vm(struct mm_struct *mm, unsigned long npages)
2140{
2141 unsigned long cur = mm->total_vm; /* pages */
2142 unsigned long lim;
2143
2144 lim = current->signal->rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT;
2145
2146 if (cur + npages > lim)
2147 return 0;
2148 return 1;
2149}
Roland McGrathfa5dc222007-02-08 14:20:41 -08002150
2151
2152static struct page *special_mapping_nopage(struct vm_area_struct *vma,
2153 unsigned long address, int *type)
2154{
2155 struct page **pages;
2156
2157 BUG_ON(address < vma->vm_start || address >= vma->vm_end);
2158
2159 address -= vma->vm_start;
2160 for (pages = vma->vm_private_data; address > 0 && *pages; ++pages)
2161 address -= PAGE_SIZE;
2162
2163 if (*pages) {
2164 struct page *page = *pages;
2165 get_page(page);
2166 return page;
2167 }
2168
2169 return NOPAGE_SIGBUS;
2170}
2171
2172/*
2173 * Having a close hook prevents vma merging regardless of flags.
2174 */
2175static void special_mapping_close(struct vm_area_struct *vma)
2176{
2177}
2178
2179static struct vm_operations_struct special_mapping_vmops = {
2180 .close = special_mapping_close,
2181 .nopage = special_mapping_nopage,
2182};
2183
2184/*
2185 * Called with mm->mmap_sem held for writing.
2186 * Insert a new vma covering the given region, with the given flags.
2187 * Its pages are supplied by the given array of struct page *.
2188 * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated.
2189 * The region past the last page supplied will always produce SIGBUS.
2190 * The array pointer and the pages it points to are assumed to stay alive
2191 * for as long as this mapping might exist.
2192 */
2193int install_special_mapping(struct mm_struct *mm,
2194 unsigned long addr, unsigned long len,
2195 unsigned long vm_flags, struct page **pages)
2196{
2197 struct vm_area_struct *vma;
2198
2199 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
2200 if (unlikely(vma == NULL))
2201 return -ENOMEM;
2202
2203 vma->vm_mm = mm;
2204 vma->vm_start = addr;
2205 vma->vm_end = addr + len;
2206
2207 vma->vm_flags = vm_flags | mm->def_flags;
Coly Li3ed75eb2007-10-18 23:39:15 -07002208 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
Roland McGrathfa5dc222007-02-08 14:20:41 -08002209
2210 vma->vm_ops = &special_mapping_vmops;
2211 vma->vm_private_data = pages;
2212
2213 if (unlikely(insert_vm_struct(mm, vma))) {
2214 kmem_cache_free(vm_area_cachep, vma);
2215 return -ENOMEM;
2216 }
2217
2218 mm->total_vm += len >> PAGE_SHIFT;
2219
2220 return 0;
2221}