blob: 15678aa6ec73a4389d1c523fe542144cd3050836 [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
Eric Paris7cd94142007-11-26 18:47:40 -0500915 if (!(flags & MAP_FIXED))
916 addr = round_hint_to_min(addr);
917
Kirill Korotaev3a459752006-09-07 14:17:04 +0400918 error = arch_mmap_check(addr, len, flags);
919 if (error)
920 return error;
921
Linus Torvalds1da177e2005-04-16 15:20:36 -0700922 /* Careful about overflows.. */
923 len = PAGE_ALIGN(len);
924 if (!len || len > TASK_SIZE)
925 return -ENOMEM;
926
927 /* offset overflow? */
928 if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
929 return -EOVERFLOW;
930
931 /* Too many mappings? */
932 if (mm->map_count > sysctl_max_map_count)
933 return -ENOMEM;
934
935 /* Obtain the address to map to. we verify (or select) it and ensure
936 * that it represents a valid section of the address space.
937 */
938 addr = get_unmapped_area(file, addr, len, pgoff, flags);
939 if (addr & ~PAGE_MASK)
940 return addr;
941
942 /* Do simple checking here so the lower-level routines won't have
943 * to. we assume access permissions have been handled by the open
944 * of the memory object, so we don't do any here.
945 */
946 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) |
947 mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
948
949 if (flags & MAP_LOCKED) {
950 if (!can_do_mlock())
951 return -EPERM;
952 vm_flags |= VM_LOCKED;
953 }
954 /* mlock MCL_FUTURE? */
955 if (vm_flags & VM_LOCKED) {
956 unsigned long locked, lock_limit;
Chris Wright93ea1d02005-05-01 08:58:38 -0700957 locked = len >> PAGE_SHIFT;
958 locked += mm->locked_vm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700959 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
Chris Wright93ea1d02005-05-01 08:58:38 -0700960 lock_limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700961 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
962 return -EAGAIN;
963 }
964
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800965 inode = file ? file->f_path.dentry->d_inode : NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700966
967 if (file) {
968 switch (flags & MAP_TYPE) {
969 case MAP_SHARED:
970 if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE))
971 return -EACCES;
972
973 /*
974 * Make sure we don't allow writing to an append-only
975 * file..
976 */
977 if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE))
978 return -EACCES;
979
980 /*
981 * Make sure there are no mandatory locks on the file.
982 */
983 if (locks_verify_locked(inode))
984 return -EAGAIN;
985
986 vm_flags |= VM_SHARED | VM_MAYSHARE;
987 if (!(file->f_mode & FMODE_WRITE))
988 vm_flags &= ~(VM_MAYWRITE | VM_SHARED);
989
990 /* fall through */
991 case MAP_PRIVATE:
992 if (!(file->f_mode & FMODE_READ))
993 return -EACCES;
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -0800994 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
Linus Torvalds80c56062006-10-15 14:09:55 -0700995 if (vm_flags & VM_EXEC)
996 return -EPERM;
997 vm_flags &= ~VM_MAYEXEC;
998 }
999 if (is_file_hugepages(file))
1000 accountable = 0;
1001
1002 if (!file->f_op || !file->f_op->mmap)
1003 return -ENODEV;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001004 break;
1005
1006 default:
1007 return -EINVAL;
1008 }
1009 } else {
1010 switch (flags & MAP_TYPE) {
1011 case MAP_SHARED:
1012 vm_flags |= VM_SHARED | VM_MAYSHARE;
1013 break;
1014 case MAP_PRIVATE:
1015 /*
1016 * Set pgoff according to addr for anon_vma.
1017 */
1018 pgoff = addr >> PAGE_SHIFT;
1019 break;
1020 default:
1021 return -EINVAL;
1022 }
1023 }
1024
Eric Parised032182007-06-28 15:55:21 -04001025 error = security_file_mmap(file, reqprot, prot, flags, addr, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001026 if (error)
1027 return error;
Eric Parised032182007-06-28 15:55:21 -04001028
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001029 return mmap_region(file, addr, len, flags, vm_flags, pgoff,
1030 accountable);
1031}
1032EXPORT_SYMBOL(do_mmap_pgoff);
1033
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001034/*
1035 * Some shared mappigns will want the pages marked read-only
1036 * to track write events. If so, we'll downgrade vm_page_prot
1037 * to the private version (using protection_map[] without the
1038 * VM_SHARED bit).
1039 */
1040int vma_wants_writenotify(struct vm_area_struct *vma)
1041{
1042 unsigned int vm_flags = vma->vm_flags;
1043
1044 /* If it was private or non-writable, the write bit is already clear */
1045 if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED)))
1046 return 0;
1047
1048 /* The backer wishes to know when pages are first written to? */
1049 if (vma->vm_ops && vma->vm_ops->page_mkwrite)
1050 return 1;
1051
1052 /* The open routine did something to the protections already? */
1053 if (pgprot_val(vma->vm_page_prot) !=
Coly Li3ed75eb2007-10-18 23:39:15 -07001054 pgprot_val(vm_get_page_prot(vm_flags)))
Alexey Dobriyan4e950f62007-07-30 02:36:13 +04001055 return 0;
1056
1057 /* Specialty mapping? */
1058 if (vm_flags & (VM_PFNMAP|VM_INSERTPAGE))
1059 return 0;
1060
1061 /* Can the mapping track the dirty pages? */
1062 return vma->vm_file && vma->vm_file->f_mapping &&
1063 mapping_cap_account_dirty(vma->vm_file->f_mapping);
1064}
1065
1066
Miklos Szeredi0165ab42007-07-15 23:38:26 -07001067unsigned long mmap_region(struct file *file, unsigned long addr,
1068 unsigned long len, unsigned long flags,
1069 unsigned int vm_flags, unsigned long pgoff,
1070 int accountable)
1071{
1072 struct mm_struct *mm = current->mm;
1073 struct vm_area_struct *vma, *prev;
1074 int correct_wcount = 0;
1075 int error;
1076 struct rb_node **rb_link, *rb_parent;
1077 unsigned long charged = 0;
1078 struct inode *inode = file ? file->f_path.dentry->d_inode : NULL;
1079
Linus Torvalds1da177e2005-04-16 15:20:36 -07001080 /* Clear old maps */
1081 error = -ENOMEM;
1082munmap_back:
1083 vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
1084 if (vma && vma->vm_start < addr + len) {
1085 if (do_munmap(mm, addr, len))
1086 return -ENOMEM;
1087 goto munmap_back;
1088 }
1089
1090 /* Check against address space limit. */
akpm@osdl.org119f6572005-05-01 08:58:35 -07001091 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001092 return -ENOMEM;
1093
1094 if (accountable && (!(flags & MAP_NORESERVE) ||
1095 sysctl_overcommit_memory == OVERCOMMIT_NEVER)) {
1096 if (vm_flags & VM_SHARED) {
1097 /* Check memory availability in shmem_file_setup? */
1098 vm_flags |= VM_ACCOUNT;
1099 } else if (vm_flags & VM_WRITE) {
1100 /*
1101 * Private writable mapping: check memory availability
1102 */
1103 charged = len >> PAGE_SHIFT;
1104 if (security_vm_enough_memory(charged))
1105 return -ENOMEM;
1106 vm_flags |= VM_ACCOUNT;
1107 }
1108 }
1109
1110 /*
1111 * Can we just expand an old private anonymous mapping?
1112 * The VM_SHARED test is necessary because shmem_zero_setup
1113 * will create the file object for a shared anonymous map below.
1114 */
1115 if (!file && !(vm_flags & VM_SHARED) &&
1116 vma_merge(mm, prev, addr, addr + len, vm_flags,
1117 NULL, NULL, pgoff, NULL))
1118 goto out;
1119
1120 /*
1121 * Determine the object being mapped and call the appropriate
1122 * specific mapper. the address has already been validated, but
1123 * not unmapped, but the maps are removed from the list.
1124 */
Pekka Enbergc5e3b832006-03-25 03:06:43 -08001125 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001126 if (!vma) {
1127 error = -ENOMEM;
1128 goto unacct_error;
1129 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001130
1131 vma->vm_mm = mm;
1132 vma->vm_start = addr;
1133 vma->vm_end = addr + len;
1134 vma->vm_flags = vm_flags;
Coly Li3ed75eb2007-10-18 23:39:15 -07001135 vma->vm_page_prot = vm_get_page_prot(vm_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001136 vma->vm_pgoff = pgoff;
1137
1138 if (file) {
1139 error = -EINVAL;
1140 if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
1141 goto free_vma;
1142 if (vm_flags & VM_DENYWRITE) {
1143 error = deny_write_access(file);
1144 if (error)
1145 goto free_vma;
1146 correct_wcount = 1;
1147 }
1148 vma->vm_file = file;
1149 get_file(file);
1150 error = file->f_op->mmap(file, vma);
1151 if (error)
1152 goto unmap_and_free_vma;
1153 } else if (vm_flags & VM_SHARED) {
1154 error = shmem_zero_setup(vma);
1155 if (error)
1156 goto free_vma;
1157 }
1158
1159 /* We set VM_ACCOUNT in a shared mapping's vm_flags, to inform
1160 * shmem_zero_setup (perhaps called through /dev/zero's ->mmap)
1161 * that memory reservation must be checked; but that reservation
1162 * belongs to shared memory object, not to vma: so now clear it.
1163 */
1164 if ((vm_flags & (VM_SHARED|VM_ACCOUNT)) == (VM_SHARED|VM_ACCOUNT))
1165 vma->vm_flags &= ~VM_ACCOUNT;
1166
1167 /* Can addr have changed??
1168 *
1169 * Answer: Yes, several device drivers can do it in their
1170 * f_op->mmap method. -DaveM
1171 */
1172 addr = vma->vm_start;
1173 pgoff = vma->vm_pgoff;
1174 vm_flags = vma->vm_flags;
1175
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001176 if (vma_wants_writenotify(vma))
Hugh Dickins1ddd4392007-10-22 20:45:12 -07001177 vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED);
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001178
Linus Torvalds1da177e2005-04-16 15:20:36 -07001179 if (!file || !vma_merge(mm, prev, addr, vma->vm_end,
1180 vma->vm_flags, NULL, file, pgoff, vma_policy(vma))) {
1181 file = vma->vm_file;
1182 vma_link(mm, vma, prev, rb_link, rb_parent);
1183 if (correct_wcount)
1184 atomic_inc(&inode->i_writecount);
1185 } else {
1186 if (file) {
1187 if (correct_wcount)
1188 atomic_inc(&inode->i_writecount);
1189 fput(file);
1190 }
1191 mpol_free(vma_policy(vma));
1192 kmem_cache_free(vm_area_cachep, vma);
1193 }
1194out:
1195 mm->total_vm += len >> PAGE_SHIFT;
Hugh Dickinsab50b8e2005-10-29 18:15:56 -07001196 vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001197 if (vm_flags & VM_LOCKED) {
1198 mm->locked_vm += len >> PAGE_SHIFT;
1199 make_pages_present(addr, addr + len);
1200 }
Nick Piggin54cb8822007-07-19 01:46:59 -07001201 if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK))
1202 make_pages_present(addr, addr + len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001203 return addr;
1204
1205unmap_and_free_vma:
1206 if (correct_wcount)
1207 atomic_inc(&inode->i_writecount);
1208 vma->vm_file = NULL;
1209 fput(file);
1210
1211 /* Undo any partial mapping done by a device driver. */
Hugh Dickinse0da3822005-04-19 13:29:15 -07001212 unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end);
1213 charged = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001214free_vma:
1215 kmem_cache_free(vm_area_cachep, vma);
1216unacct_error:
1217 if (charged)
1218 vm_unacct_memory(charged);
1219 return error;
1220}
1221
Linus Torvalds1da177e2005-04-16 15:20:36 -07001222/* Get an address range which is currently unmapped.
1223 * For shmat() with addr=0.
1224 *
1225 * Ugly calling convention alert:
1226 * Return value with the low bits set means error value,
1227 * ie
1228 * if (ret & ~PAGE_MASK)
1229 * error = ret;
1230 *
1231 * This function "knows" that -ENOMEM has the bits set.
1232 */
1233#ifndef HAVE_ARCH_UNMAPPED_AREA
1234unsigned long
1235arch_get_unmapped_area(struct file *filp, unsigned long addr,
1236 unsigned long len, unsigned long pgoff, unsigned long flags)
1237{
1238 struct mm_struct *mm = current->mm;
1239 struct vm_area_struct *vma;
1240 unsigned long start_addr;
1241
1242 if (len > TASK_SIZE)
1243 return -ENOMEM;
1244
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001245 if (flags & MAP_FIXED)
1246 return addr;
1247
Linus Torvalds1da177e2005-04-16 15:20:36 -07001248 if (addr) {
1249 addr = PAGE_ALIGN(addr);
1250 vma = find_vma(mm, addr);
1251 if (TASK_SIZE - len >= addr &&
1252 (!vma || addr + len <= vma->vm_start))
1253 return addr;
1254 }
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001255 if (len > mm->cached_hole_size) {
1256 start_addr = addr = mm->free_area_cache;
1257 } else {
1258 start_addr = addr = TASK_UNMAPPED_BASE;
1259 mm->cached_hole_size = 0;
1260 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001261
1262full_search:
1263 for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
1264 /* At this point: (!vma || addr < vma->vm_end). */
1265 if (TASK_SIZE - len < addr) {
1266 /*
1267 * Start a new search - just in case we missed
1268 * some holes.
1269 */
1270 if (start_addr != TASK_UNMAPPED_BASE) {
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001271 addr = TASK_UNMAPPED_BASE;
1272 start_addr = addr;
1273 mm->cached_hole_size = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001274 goto full_search;
1275 }
1276 return -ENOMEM;
1277 }
1278 if (!vma || addr + len <= vma->vm_start) {
1279 /*
1280 * Remember the place where we stopped the search:
1281 */
1282 mm->free_area_cache = addr + len;
1283 return addr;
1284 }
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001285 if (addr + mm->cached_hole_size < vma->vm_start)
1286 mm->cached_hole_size = vma->vm_start - addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001287 addr = vma->vm_end;
1288 }
1289}
1290#endif
1291
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001292void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001293{
1294 /*
1295 * Is this a new hole at the lowest possible address?
1296 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001297 if (addr >= TASK_UNMAPPED_BASE && addr < mm->free_area_cache) {
1298 mm->free_area_cache = addr;
1299 mm->cached_hole_size = ~0UL;
1300 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001301}
1302
1303/*
1304 * This mmap-allocator allocates new areas top-down from below the
1305 * stack's low limit (the base):
1306 */
1307#ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
1308unsigned long
1309arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
1310 const unsigned long len, const unsigned long pgoff,
1311 const unsigned long flags)
1312{
1313 struct vm_area_struct *vma;
1314 struct mm_struct *mm = current->mm;
1315 unsigned long addr = addr0;
1316
1317 /* requested length too big for entire address space */
1318 if (len > TASK_SIZE)
1319 return -ENOMEM;
1320
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001321 if (flags & MAP_FIXED)
1322 return addr;
1323
Linus Torvalds1da177e2005-04-16 15:20:36 -07001324 /* requesting a specific address */
1325 if (addr) {
1326 addr = PAGE_ALIGN(addr);
1327 vma = find_vma(mm, addr);
1328 if (TASK_SIZE - len >= addr &&
1329 (!vma || addr + len <= vma->vm_start))
1330 return addr;
1331 }
1332
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001333 /* check if free_area_cache is useful for us */
1334 if (len <= mm->cached_hole_size) {
1335 mm->cached_hole_size = 0;
1336 mm->free_area_cache = mm->mmap_base;
1337 }
1338
Linus Torvalds1da177e2005-04-16 15:20:36 -07001339 /* either no address requested or can't fit in requested address hole */
1340 addr = mm->free_area_cache;
1341
1342 /* make sure it can fit in the remaining address space */
Linus Torvalds49a43872005-05-18 15:39:33 -07001343 if (addr > len) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001344 vma = find_vma(mm, addr-len);
1345 if (!vma || addr <= vma->vm_start)
1346 /* remember the address as a hint for next time */
1347 return (mm->free_area_cache = addr-len);
1348 }
1349
Chris Wright73219d12005-06-21 17:14:52 -07001350 if (mm->mmap_base < len)
1351 goto bottomup;
1352
Linus Torvalds1da177e2005-04-16 15:20:36 -07001353 addr = mm->mmap_base-len;
1354
1355 do {
1356 /*
1357 * Lookup failure means no vma is above this address,
1358 * else if new region fits below vma->vm_start,
1359 * return with success:
1360 */
1361 vma = find_vma(mm, addr);
1362 if (!vma || addr+len <= vma->vm_start)
1363 /* remember the address as a hint for next time */
1364 return (mm->free_area_cache = addr);
1365
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001366 /* remember the largest hole we saw so far */
1367 if (addr + mm->cached_hole_size < vma->vm_start)
1368 mm->cached_hole_size = vma->vm_start - addr;
1369
Linus Torvalds1da177e2005-04-16 15:20:36 -07001370 /* try just below the current vma->vm_start */
1371 addr = vma->vm_start-len;
Linus Torvalds49a43872005-05-18 15:39:33 -07001372 } while (len < vma->vm_start);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001373
Chris Wright73219d12005-06-21 17:14:52 -07001374bottomup:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001375 /*
1376 * A failed mmap() very likely causes application failure,
1377 * so fall back to the bottom-up function here. This scenario
1378 * can happen with large stack limits and large mmap()
1379 * allocations.
1380 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001381 mm->cached_hole_size = ~0UL;
1382 mm->free_area_cache = TASK_UNMAPPED_BASE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001383 addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
1384 /*
1385 * Restore the topdown base:
1386 */
1387 mm->free_area_cache = mm->mmap_base;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001388 mm->cached_hole_size = ~0UL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001389
1390 return addr;
1391}
1392#endif
1393
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001394void arch_unmap_area_topdown(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001395{
1396 /*
1397 * Is this a new hole at the highest possible address?
1398 */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001399 if (addr > mm->free_area_cache)
1400 mm->free_area_cache = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001401
1402 /* dont allow allocations above current base */
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001403 if (mm->free_area_cache > mm->mmap_base)
1404 mm->free_area_cache = mm->mmap_base;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001405}
1406
1407unsigned long
1408get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
1409 unsigned long pgoff, unsigned long flags)
1410{
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001411 unsigned long (*get_area)(struct file *, unsigned long,
1412 unsigned long, unsigned long, unsigned long);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001413
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001414 get_area = current->mm->get_unmapped_area;
1415 if (file && file->f_op && file->f_op->get_unmapped_area)
1416 get_area = file->f_op->get_unmapped_area;
1417 addr = get_area(file, addr, len, pgoff, flags);
1418 if (IS_ERR_VALUE(addr))
1419 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001420
Linus Torvalds07ab67c2005-05-19 22:43:37 -07001421 if (addr > TASK_SIZE - len)
1422 return -ENOMEM;
1423 if (addr & ~PAGE_MASK)
1424 return -EINVAL;
Benjamin Herrenschmidt06abdfb2007-05-06 14:50:13 -07001425
Linus Torvalds07ab67c2005-05-19 22:43:37 -07001426 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001427}
1428
1429EXPORT_SYMBOL(get_unmapped_area);
1430
1431/* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
1432struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr)
1433{
1434 struct vm_area_struct *vma = NULL;
1435
1436 if (mm) {
1437 /* Check the cache first. */
1438 /* (Cache hit rate is typically around 35%.) */
1439 vma = mm->mmap_cache;
1440 if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) {
1441 struct rb_node * rb_node;
1442
1443 rb_node = mm->mm_rb.rb_node;
1444 vma = NULL;
1445
1446 while (rb_node) {
1447 struct vm_area_struct * vma_tmp;
1448
1449 vma_tmp = rb_entry(rb_node,
1450 struct vm_area_struct, vm_rb);
1451
1452 if (vma_tmp->vm_end > addr) {
1453 vma = vma_tmp;
1454 if (vma_tmp->vm_start <= addr)
1455 break;
1456 rb_node = rb_node->rb_left;
1457 } else
1458 rb_node = rb_node->rb_right;
1459 }
1460 if (vma)
1461 mm->mmap_cache = vma;
1462 }
1463 }
1464 return vma;
1465}
1466
1467EXPORT_SYMBOL(find_vma);
1468
1469/* Same as find_vma, but also return a pointer to the previous VMA in *pprev. */
1470struct vm_area_struct *
1471find_vma_prev(struct mm_struct *mm, unsigned long addr,
1472 struct vm_area_struct **pprev)
1473{
1474 struct vm_area_struct *vma = NULL, *prev = NULL;
1475 struct rb_node * rb_node;
1476 if (!mm)
1477 goto out;
1478
1479 /* Guard against addr being lower than the first VMA */
1480 vma = mm->mmap;
1481
1482 /* Go through the RB tree quickly. */
1483 rb_node = mm->mm_rb.rb_node;
1484
1485 while (rb_node) {
1486 struct vm_area_struct *vma_tmp;
1487 vma_tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb);
1488
1489 if (addr < vma_tmp->vm_end) {
1490 rb_node = rb_node->rb_left;
1491 } else {
1492 prev = vma_tmp;
1493 if (!prev->vm_next || (addr < prev->vm_next->vm_end))
1494 break;
1495 rb_node = rb_node->rb_right;
1496 }
1497 }
1498
1499out:
1500 *pprev = prev;
1501 return prev ? prev->vm_next : vma;
1502}
1503
1504/*
1505 * Verify that the stack growth is acceptable and
1506 * update accounting. This is shared with both the
1507 * grow-up and grow-down cases.
1508 */
1509static int acct_stack_growth(struct vm_area_struct * vma, unsigned long size, unsigned long grow)
1510{
1511 struct mm_struct *mm = vma->vm_mm;
1512 struct rlimit *rlim = current->signal->rlim;
Adam Litke0d59a012007-01-30 14:35:39 -08001513 unsigned long new_start;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001514
1515 /* address space limit tests */
akpm@osdl.org119f6572005-05-01 08:58:35 -07001516 if (!may_expand_vm(mm, grow))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001517 return -ENOMEM;
1518
1519 /* Stack limit test */
1520 if (size > rlim[RLIMIT_STACK].rlim_cur)
1521 return -ENOMEM;
1522
1523 /* mlock limit tests */
1524 if (vma->vm_flags & VM_LOCKED) {
1525 unsigned long locked;
1526 unsigned long limit;
1527 locked = mm->locked_vm + grow;
1528 limit = rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT;
1529 if (locked > limit && !capable(CAP_IPC_LOCK))
1530 return -ENOMEM;
1531 }
1532
Adam Litke0d59a012007-01-30 14:35:39 -08001533 /* Check to ensure the stack will not grow into a hugetlb-only region */
1534 new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start :
1535 vma->vm_end - size;
1536 if (is_hugepage_only_range(vma->vm_mm, new_start, size))
1537 return -EFAULT;
1538
Linus Torvalds1da177e2005-04-16 15:20:36 -07001539 /*
1540 * Overcommit.. This must be the final test, as it will
1541 * update security statistics.
1542 */
1543 if (security_vm_enough_memory(grow))
1544 return -ENOMEM;
1545
1546 /* Ok, everything looks good - let it rip */
1547 mm->total_vm += grow;
1548 if (vma->vm_flags & VM_LOCKED)
1549 mm->locked_vm += grow;
Hugh Dickinsab50b8e2005-10-29 18:15:56 -07001550 vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001551 return 0;
1552}
1553
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001554#if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001555/*
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001556 * PA-RISC uses this for its stack; IA64 for its Register Backing Store.
1557 * vma is the last one with address > vma->vm_end. Have to extend vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001558 */
Matthew Wilcox9ab88512005-11-18 16:16:42 -05001559#ifndef CONFIG_IA64
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001560static inline
1561#endif
1562int expand_upwards(struct vm_area_struct *vma, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001563{
1564 int error;
1565
1566 if (!(vma->vm_flags & VM_GROWSUP))
1567 return -EFAULT;
1568
1569 /*
1570 * We must make sure the anon_vma is allocated
1571 * so that the anon_vma locking is not a noop.
1572 */
1573 if (unlikely(anon_vma_prepare(vma)))
1574 return -ENOMEM;
1575 anon_vma_lock(vma);
1576
1577 /*
1578 * vma->vm_start/vm_end cannot change under us because the caller
1579 * is required to hold the mmap_sem in read mode. We need the
1580 * anon_vma lock to serialize against concurrent expand_stacks.
Helge Deller06b32f32006-12-19 19:28:33 +01001581 * Also guard against wrapping around to address 0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001582 */
Helge Deller06b32f32006-12-19 19:28:33 +01001583 if (address < PAGE_ALIGN(address+4))
1584 address = PAGE_ALIGN(address+4);
1585 else {
1586 anon_vma_unlock(vma);
1587 return -ENOMEM;
1588 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001589 error = 0;
1590
1591 /* Somebody else might have raced and expanded it already */
1592 if (address > vma->vm_end) {
1593 unsigned long size, grow;
1594
1595 size = address - vma->vm_start;
1596 grow = (address - vma->vm_end) >> PAGE_SHIFT;
1597
1598 error = acct_stack_growth(vma, size, grow);
1599 if (!error)
1600 vma->vm_end = address;
1601 }
1602 anon_vma_unlock(vma);
1603 return error;
1604}
Hugh Dickins46dea3d2005-10-29 18:16:20 -07001605#endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
1606
Linus Torvalds1da177e2005-04-16 15:20:36 -07001607/*
1608 * vma is the first one with address < vma->vm_start. Have to extend vma.
1609 */
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001610static inline int expand_downwards(struct vm_area_struct *vma,
1611 unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001612{
1613 int error;
1614
1615 /*
1616 * We must make sure the anon_vma is allocated
1617 * so that the anon_vma locking is not a noop.
1618 */
1619 if (unlikely(anon_vma_prepare(vma)))
1620 return -ENOMEM;
Eric Paris88694772007-11-26 18:47:26 -05001621
1622 address &= PAGE_MASK;
1623 error = security_file_mmap(0, 0, 0, 0, address, 1);
1624 if (error)
1625 return error;
1626
Linus Torvalds1da177e2005-04-16 15:20:36 -07001627 anon_vma_lock(vma);
1628
1629 /*
1630 * vma->vm_start/vm_end cannot change under us because the caller
1631 * is required to hold the mmap_sem in read mode. We need the
1632 * anon_vma lock to serialize against concurrent expand_stacks.
1633 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001634
1635 /* Somebody else might have raced and expanded it already */
1636 if (address < vma->vm_start) {
1637 unsigned long size, grow;
1638
1639 size = vma->vm_end - address;
1640 grow = (vma->vm_start - address) >> PAGE_SHIFT;
1641
1642 error = acct_stack_growth(vma, size, grow);
1643 if (!error) {
1644 vma->vm_start = address;
1645 vma->vm_pgoff -= grow;
1646 }
1647 }
1648 anon_vma_unlock(vma);
1649 return error;
1650}
1651
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001652int expand_stack_downwards(struct vm_area_struct *vma, unsigned long address)
1653{
1654 return expand_downwards(vma, address);
1655}
1656
1657#ifdef CONFIG_STACK_GROWSUP
1658int expand_stack(struct vm_area_struct *vma, unsigned long address)
1659{
1660 return expand_upwards(vma, address);
1661}
1662
1663struct vm_area_struct *
1664find_extend_vma(struct mm_struct *mm, unsigned long addr)
1665{
1666 struct vm_area_struct *vma, *prev;
1667
1668 addr &= PAGE_MASK;
1669 vma = find_vma_prev(mm, addr, &prev);
1670 if (vma && (vma->vm_start <= addr))
1671 return vma;
1672 if (!prev || expand_stack(prev, addr))
1673 return NULL;
1674 if (prev->vm_flags & VM_LOCKED)
1675 make_pages_present(addr, prev->vm_end);
1676 return prev;
1677}
1678#else
1679int expand_stack(struct vm_area_struct *vma, unsigned long address)
1680{
1681 return expand_downwards(vma, address);
1682}
1683
Linus Torvalds1da177e2005-04-16 15:20:36 -07001684struct vm_area_struct *
1685find_extend_vma(struct mm_struct * mm, unsigned long addr)
1686{
1687 struct vm_area_struct * vma;
1688 unsigned long start;
1689
1690 addr &= PAGE_MASK;
1691 vma = find_vma(mm,addr);
1692 if (!vma)
1693 return NULL;
1694 if (vma->vm_start <= addr)
1695 return vma;
1696 if (!(vma->vm_flags & VM_GROWSDOWN))
1697 return NULL;
1698 start = vma->vm_start;
1699 if (expand_stack(vma, addr))
1700 return NULL;
Ollie Wildb6a2fea2007-07-19 01:48:16 -07001701 if (vma->vm_flags & VM_LOCKED)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001702 make_pages_present(addr, start);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001703 return vma;
1704}
1705#endif
1706
Linus Torvalds1da177e2005-04-16 15:20:36 -07001707/*
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001708 * Ok - we have the memory areas we should free on the vma list,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001709 * so release them, and do the vma updates.
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001710 *
1711 * Called with the mm semaphore held.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001712 */
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001713static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001714{
Hugh Dickins365e9c872005-10-29 18:16:18 -07001715 /* Update high watermark before we lower total_vm */
1716 update_hiwater_vm(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001717 do {
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001718 long nrpages = vma_pages(vma);
1719
1720 mm->total_vm -= nrpages;
1721 if (vma->vm_flags & VM_LOCKED)
1722 mm->locked_vm -= nrpages;
1723 vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages);
Hugh Dickinsa8fb5612005-10-29 18:15:57 -07001724 vma = remove_vma(vma);
Hugh Dickins146425a2005-04-19 13:29:18 -07001725 } while (vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001726 validate_mm(mm);
1727}
1728
1729/*
1730 * Get rid of page table information in the indicated region.
1731 *
Paolo 'Blaisorblade' Giarrussof10df682005-09-21 09:55:37 -07001732 * Called with the mm semaphore held.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001733 */
1734static void unmap_region(struct mm_struct *mm,
Hugh Dickinse0da3822005-04-19 13:29:15 -07001735 struct vm_area_struct *vma, struct vm_area_struct *prev,
1736 unsigned long start, unsigned long end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001737{
Hugh Dickinse0da3822005-04-19 13:29:15 -07001738 struct vm_area_struct *next = prev? prev->vm_next: mm->mmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001739 struct mmu_gather *tlb;
1740 unsigned long nr_accounted = 0;
1741
1742 lru_add_drain();
1743 tlb = tlb_gather_mmu(mm, 0);
Hugh Dickins365e9c872005-10-29 18:16:18 -07001744 update_hiwater_rss(mm);
Hugh Dickins508034a2005-10-29 18:16:30 -07001745 unmap_vmas(&tlb, vma, start, end, &nr_accounted, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001746 vm_unacct_memory(nr_accounted);
Hugh Dickinse2cdef82005-04-19 13:29:19 -07001747 free_pgtables(&tlb, vma, prev? prev->vm_end: FIRST_USER_ADDRESS,
Hugh Dickinse0da3822005-04-19 13:29:15 -07001748 next? next->vm_start: 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001749 tlb_finish_mmu(tlb, start, end);
1750}
1751
1752/*
1753 * Create a list of vma's touched by the unmap, removing them from the mm's
1754 * vma list as we go..
1755 */
1756static void
1757detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
1758 struct vm_area_struct *prev, unsigned long end)
1759{
1760 struct vm_area_struct **insertion_point;
1761 struct vm_area_struct *tail_vma = NULL;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001762 unsigned long addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001763
1764 insertion_point = (prev ? &prev->vm_next : &mm->mmap);
1765 do {
1766 rb_erase(&vma->vm_rb, &mm->mm_rb);
1767 mm->map_count--;
1768 tail_vma = vma;
1769 vma = vma->vm_next;
1770 } while (vma && vma->vm_start < end);
1771 *insertion_point = vma;
1772 tail_vma->vm_next = NULL;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001773 if (mm->unmap_area == arch_unmap_area)
1774 addr = prev ? prev->vm_end : mm->mmap_base;
1775 else
1776 addr = vma ? vma->vm_start : mm->mmap_base;
1777 mm->unmap_area(mm, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001778 mm->mmap_cache = NULL; /* Kill the cache. */
1779}
1780
1781/*
1782 * Split a vma into two pieces at address 'addr', a new vma is allocated
Michael Opdenacker59c51592007-05-09 08:57:56 +02001783 * either for the first part or the tail.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001784 */
1785int split_vma(struct mm_struct * mm, struct vm_area_struct * vma,
1786 unsigned long addr, int new_below)
1787{
1788 struct mempolicy *pol;
1789 struct vm_area_struct *new;
1790
1791 if (is_vm_hugetlb_page(vma) && (addr & ~HPAGE_MASK))
1792 return -EINVAL;
1793
1794 if (mm->map_count >= sysctl_max_map_count)
1795 return -ENOMEM;
1796
Christoph Lametere94b1762006-12-06 20:33:17 -08001797 new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001798 if (!new)
1799 return -ENOMEM;
1800
1801 /* most fields are the same, copy all, and then fixup */
1802 *new = *vma;
1803
1804 if (new_below)
1805 new->vm_end = addr;
1806 else {
1807 new->vm_start = addr;
1808 new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT);
1809 }
1810
1811 pol = mpol_copy(vma_policy(vma));
1812 if (IS_ERR(pol)) {
1813 kmem_cache_free(vm_area_cachep, new);
1814 return PTR_ERR(pol);
1815 }
1816 vma_set_policy(new, pol);
1817
1818 if (new->vm_file)
1819 get_file(new->vm_file);
1820
1821 if (new->vm_ops && new->vm_ops->open)
1822 new->vm_ops->open(new);
1823
1824 if (new_below)
1825 vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff +
1826 ((addr - new->vm_start) >> PAGE_SHIFT), new);
1827 else
1828 vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new);
1829
1830 return 0;
1831}
1832
1833/* Munmap is split into 2 main parts -- this part which finds
1834 * what needs doing, and the areas themselves, which do the
1835 * work. This now handles partial unmappings.
1836 * Jeremy Fitzhardinge <jeremy@goop.org>
1837 */
1838int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
1839{
1840 unsigned long end;
Hugh Dickins146425a2005-04-19 13:29:18 -07001841 struct vm_area_struct *vma, *prev, *last;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001842
1843 if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start)
1844 return -EINVAL;
1845
1846 if ((len = PAGE_ALIGN(len)) == 0)
1847 return -EINVAL;
1848
1849 /* Find the first overlapping VMA */
Hugh Dickins146425a2005-04-19 13:29:18 -07001850 vma = find_vma_prev(mm, start, &prev);
1851 if (!vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001852 return 0;
Hugh Dickins146425a2005-04-19 13:29:18 -07001853 /* we have start < vma->vm_end */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001854
1855 /* if it doesn't overlap, we have nothing.. */
1856 end = start + len;
Hugh Dickins146425a2005-04-19 13:29:18 -07001857 if (vma->vm_start >= end)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001858 return 0;
1859
1860 /*
1861 * If we need to split any vma, do it now to save pain later.
1862 *
1863 * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially
1864 * unmapped vm_area_struct will remain in use: so lower split_vma
1865 * places tmp vma above, and higher split_vma places tmp vma below.
1866 */
Hugh Dickins146425a2005-04-19 13:29:18 -07001867 if (start > vma->vm_start) {
1868 int error = split_vma(mm, vma, start, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001869 if (error)
1870 return error;
Hugh Dickins146425a2005-04-19 13:29:18 -07001871 prev = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001872 }
1873
1874 /* Does it split the last one? */
1875 last = find_vma(mm, end);
1876 if (last && end > last->vm_start) {
1877 int error = split_vma(mm, last, end, 1);
1878 if (error)
1879 return error;
1880 }
Hugh Dickins146425a2005-04-19 13:29:18 -07001881 vma = prev? prev->vm_next: mm->mmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001882
1883 /*
1884 * Remove the vma's, and unmap the actual pages
1885 */
Hugh Dickins146425a2005-04-19 13:29:18 -07001886 detach_vmas_to_be_unmapped(mm, vma, prev, end);
1887 unmap_region(mm, vma, prev, start, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001888
1889 /* Fix up all other VM information */
Hugh Dickins2c0b3812005-10-29 18:15:56 -07001890 remove_vma_list(mm, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001891
1892 return 0;
1893}
1894
1895EXPORT_SYMBOL(do_munmap);
1896
1897asmlinkage long sys_munmap(unsigned long addr, size_t len)
1898{
1899 int ret;
1900 struct mm_struct *mm = current->mm;
1901
1902 profile_munmap(addr);
1903
1904 down_write(&mm->mmap_sem);
1905 ret = do_munmap(mm, addr, len);
1906 up_write(&mm->mmap_sem);
1907 return ret;
1908}
1909
1910static inline void verify_mm_writelocked(struct mm_struct *mm)
1911{
Paul E. McKenneya241ec62005-10-30 15:03:12 -08001912#ifdef CONFIG_DEBUG_VM
Linus Torvalds1da177e2005-04-16 15:20:36 -07001913 if (unlikely(down_read_trylock(&mm->mmap_sem))) {
1914 WARN_ON(1);
1915 up_read(&mm->mmap_sem);
1916 }
1917#endif
1918}
1919
1920/*
1921 * this is really a simplified "do_mmap". it only handles
1922 * anonymous maps. eventually we may be able to do some
1923 * brk-specific accounting here.
1924 */
1925unsigned long do_brk(unsigned long addr, unsigned long len)
1926{
1927 struct mm_struct * mm = current->mm;
1928 struct vm_area_struct * vma, * prev;
1929 unsigned long flags;
1930 struct rb_node ** rb_link, * rb_parent;
1931 pgoff_t pgoff = addr >> PAGE_SHIFT;
Kirill Korotaev3a459752006-09-07 14:17:04 +04001932 int error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001933
1934 len = PAGE_ALIGN(len);
1935 if (!len)
1936 return addr;
1937
1938 if ((addr + len) > TASK_SIZE || (addr + len) < addr)
1939 return -EINVAL;
1940
Hugh Dickinscd2579d2006-11-14 13:43:38 +00001941 if (is_hugepage_only_range(mm, addr, len))
1942 return -EINVAL;
David Gibsoncb07c9a2006-11-14 02:03:38 -08001943
Eric Paris5a211a52007-12-04 11:06:55 -05001944 error = security_file_mmap(0, 0, 0, 0, addr, 1);
1945 if (error)
1946 return error;
1947
Kirill Korotaev3a459752006-09-07 14:17:04 +04001948 flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags;
1949
1950 error = arch_mmap_check(addr, len, flags);
1951 if (error)
1952 return error;
1953
Linus Torvalds1da177e2005-04-16 15:20:36 -07001954 /*
1955 * mlock MCL_FUTURE?
1956 */
1957 if (mm->def_flags & VM_LOCKED) {
1958 unsigned long locked, lock_limit;
Chris Wright93ea1d02005-05-01 08:58:38 -07001959 locked = len >> PAGE_SHIFT;
1960 locked += mm->locked_vm;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001961 lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
Chris Wright93ea1d02005-05-01 08:58:38 -07001962 lock_limit >>= PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001963 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
1964 return -EAGAIN;
1965 }
1966
1967 /*
1968 * mm->mmap_sem is required to protect against another thread
1969 * changing the mappings in case we sleep.
1970 */
1971 verify_mm_writelocked(mm);
1972
1973 /*
1974 * Clear old maps. this also does some error checking for us
1975 */
1976 munmap_back:
1977 vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
1978 if (vma && vma->vm_start < addr + len) {
1979 if (do_munmap(mm, addr, len))
1980 return -ENOMEM;
1981 goto munmap_back;
1982 }
1983
1984 /* Check against address space limits *after* clearing old maps... */
akpm@osdl.org119f6572005-05-01 08:58:35 -07001985 if (!may_expand_vm(mm, len >> PAGE_SHIFT))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001986 return -ENOMEM;
1987
1988 if (mm->map_count > sysctl_max_map_count)
1989 return -ENOMEM;
1990
1991 if (security_vm_enough_memory(len >> PAGE_SHIFT))
1992 return -ENOMEM;
1993
Linus Torvalds1da177e2005-04-16 15:20:36 -07001994 /* Can we just expand an old private anonymous mapping? */
1995 if (vma_merge(mm, prev, addr, addr + len, flags,
1996 NULL, NULL, pgoff, NULL))
1997 goto out;
1998
1999 /*
2000 * create a vma struct for an anonymous mapping
2001 */
Pekka Enbergc5e3b832006-03-25 03:06:43 -08002002 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002003 if (!vma) {
2004 vm_unacct_memory(len >> PAGE_SHIFT);
2005 return -ENOMEM;
2006 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002007
2008 vma->vm_mm = mm;
2009 vma->vm_start = addr;
2010 vma->vm_end = addr + len;
2011 vma->vm_pgoff = pgoff;
2012 vma->vm_flags = flags;
Coly Li3ed75eb2007-10-18 23:39:15 -07002013 vma->vm_page_prot = vm_get_page_prot(flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002014 vma_link(mm, vma, prev, rb_link, rb_parent);
2015out:
2016 mm->total_vm += len >> PAGE_SHIFT;
2017 if (flags & VM_LOCKED) {
2018 mm->locked_vm += len >> PAGE_SHIFT;
2019 make_pages_present(addr, addr + len);
2020 }
2021 return addr;
2022}
2023
2024EXPORT_SYMBOL(do_brk);
2025
2026/* Release all mmaps. */
2027void exit_mmap(struct mm_struct *mm)
2028{
2029 struct mmu_gather *tlb;
Hugh Dickinse0da3822005-04-19 13:29:15 -07002030 struct vm_area_struct *vma = mm->mmap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002031 unsigned long nr_accounted = 0;
Hugh Dickinsee39b372005-04-19 13:29:15 -07002032 unsigned long end;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002033
Jeremy Fitzhardinged6dd61c2007-05-02 19:27:14 +02002034 /* mm's last user has gone, and its about to be pulled down */
2035 arch_exit_mmap(mm);
2036
Linus Torvalds1da177e2005-04-16 15:20:36 -07002037 lru_add_drain();
Linus Torvalds1da177e2005-04-16 15:20:36 -07002038 flush_cache_mm(mm);
Hugh Dickinse0da3822005-04-19 13:29:15 -07002039 tlb = tlb_gather_mmu(mm, 1);
Hugh Dickins365e9c872005-10-29 18:16:18 -07002040 /* Don't update_hiwater_rss(mm) here, do_exit already did */
Hugh Dickinse0da3822005-04-19 13:29:15 -07002041 /* Use -1 here to ensure all VMAs in the mm are unmapped */
Hugh Dickins508034a2005-10-29 18:16:30 -07002042 end = unmap_vmas(&tlb, vma, 0, -1, &nr_accounted, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002043 vm_unacct_memory(nr_accounted);
Hugh Dickinse2cdef82005-04-19 13:29:19 -07002044 free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0);
Hugh Dickinsee39b372005-04-19 13:29:15 -07002045 tlb_finish_mmu(tlb, 0, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002046
Linus Torvalds1da177e2005-04-16 15:20:36 -07002047 /*
Hugh Dickins8f4f8c12005-10-29 18:16:29 -07002048 * Walk the list again, actually closing and freeing it,
2049 * with preemption enabled, without holding any MM locks.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002050 */
Hugh Dickinsa8fb5612005-10-29 18:15:57 -07002051 while (vma)
2052 vma = remove_vma(vma);
Hugh Dickinse0da3822005-04-19 13:29:15 -07002053
Hugh Dickinse2cdef82005-04-19 13:29:19 -07002054 BUG_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002055}
2056
2057/* Insert vm structure into process list sorted by address
2058 * and into the inode's i_mmap tree. If vm_file is non-NULL
2059 * then i_mmap_lock is taken here.
2060 */
2061int insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma)
2062{
2063 struct vm_area_struct * __vma, * prev;
2064 struct rb_node ** rb_link, * rb_parent;
2065
2066 /*
2067 * The vm_pgoff of a purely anonymous vma should be irrelevant
2068 * until its first write fault, when page's anon_vma and index
2069 * are set. But now set the vm_pgoff it will almost certainly
2070 * end up with (unless mremap moves it elsewhere before that
2071 * first wfault), so /proc/pid/maps tells a consistent story.
2072 *
2073 * By setting it to reflect the virtual start address of the
2074 * vma, merges and splits can happen in a seamless way, just
2075 * using the existing file pgoff checks and manipulations.
2076 * Similarly in do_mmap_pgoff and in do_brk.
2077 */
2078 if (!vma->vm_file) {
2079 BUG_ON(vma->anon_vma);
2080 vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT;
2081 }
2082 __vma = find_vma_prepare(mm,vma->vm_start,&prev,&rb_link,&rb_parent);
2083 if (__vma && __vma->vm_start < vma->vm_end)
2084 return -ENOMEM;
Hugh Dickins2fd4ef82005-09-14 06:13:02 +01002085 if ((vma->vm_flags & VM_ACCOUNT) &&
Alan Cox34b4e4a2007-08-22 14:01:28 -07002086 security_vm_enough_memory_mm(mm, vma_pages(vma)))
Hugh Dickins2fd4ef82005-09-14 06:13:02 +01002087 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002088 vma_link(mm, vma, prev, rb_link, rb_parent);
2089 return 0;
2090}
2091
2092/*
2093 * Copy the vma structure to a new location in the same mm,
2094 * prior to moving page table entries, to effect an mremap move.
2095 */
2096struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
2097 unsigned long addr, unsigned long len, pgoff_t pgoff)
2098{
2099 struct vm_area_struct *vma = *vmap;
2100 unsigned long vma_start = vma->vm_start;
2101 struct mm_struct *mm = vma->vm_mm;
2102 struct vm_area_struct *new_vma, *prev;
2103 struct rb_node **rb_link, *rb_parent;
2104 struct mempolicy *pol;
2105
2106 /*
2107 * If anonymous vma has not yet been faulted, update new pgoff
2108 * to match new location, to increase its chance of merging.
2109 */
2110 if (!vma->vm_file && !vma->anon_vma)
2111 pgoff = addr >> PAGE_SHIFT;
2112
2113 find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
2114 new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags,
2115 vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma));
2116 if (new_vma) {
2117 /*
2118 * Source vma may have been merged into new_vma
2119 */
2120 if (vma_start >= new_vma->vm_start &&
2121 vma_start < new_vma->vm_end)
2122 *vmap = new_vma;
2123 } else {
Christoph Lametere94b1762006-12-06 20:33:17 -08002124 new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002125 if (new_vma) {
2126 *new_vma = *vma;
2127 pol = mpol_copy(vma_policy(vma));
2128 if (IS_ERR(pol)) {
2129 kmem_cache_free(vm_area_cachep, new_vma);
2130 return NULL;
2131 }
2132 vma_set_policy(new_vma, pol);
2133 new_vma->vm_start = addr;
2134 new_vma->vm_end = addr + len;
2135 new_vma->vm_pgoff = pgoff;
2136 if (new_vma->vm_file)
2137 get_file(new_vma->vm_file);
2138 if (new_vma->vm_ops && new_vma->vm_ops->open)
2139 new_vma->vm_ops->open(new_vma);
2140 vma_link(mm, new_vma, prev, rb_link, rb_parent);
2141 }
2142 }
2143 return new_vma;
2144}
akpm@osdl.org119f6572005-05-01 08:58:35 -07002145
2146/*
2147 * Return true if the calling process may expand its vm space by the passed
2148 * number of pages
2149 */
2150int may_expand_vm(struct mm_struct *mm, unsigned long npages)
2151{
2152 unsigned long cur = mm->total_vm; /* pages */
2153 unsigned long lim;
2154
2155 lim = current->signal->rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT;
2156
2157 if (cur + npages > lim)
2158 return 0;
2159 return 1;
2160}
Roland McGrathfa5dc222007-02-08 14:20:41 -08002161
2162
2163static struct page *special_mapping_nopage(struct vm_area_struct *vma,
2164 unsigned long address, int *type)
2165{
2166 struct page **pages;
2167
2168 BUG_ON(address < vma->vm_start || address >= vma->vm_end);
2169
2170 address -= vma->vm_start;
2171 for (pages = vma->vm_private_data; address > 0 && *pages; ++pages)
2172 address -= PAGE_SIZE;
2173
2174 if (*pages) {
2175 struct page *page = *pages;
2176 get_page(page);
2177 return page;
2178 }
2179
2180 return NOPAGE_SIGBUS;
2181}
2182
2183/*
2184 * Having a close hook prevents vma merging regardless of flags.
2185 */
2186static void special_mapping_close(struct vm_area_struct *vma)
2187{
2188}
2189
2190static struct vm_operations_struct special_mapping_vmops = {
2191 .close = special_mapping_close,
2192 .nopage = special_mapping_nopage,
2193};
2194
2195/*
2196 * Called with mm->mmap_sem held for writing.
2197 * Insert a new vma covering the given region, with the given flags.
2198 * Its pages are supplied by the given array of struct page *.
2199 * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated.
2200 * The region past the last page supplied will always produce SIGBUS.
2201 * The array pointer and the pages it points to are assumed to stay alive
2202 * for as long as this mapping might exist.
2203 */
2204int install_special_mapping(struct mm_struct *mm,
2205 unsigned long addr, unsigned long len,
2206 unsigned long vm_flags, struct page **pages)
2207{
2208 struct vm_area_struct *vma;
2209
2210 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
2211 if (unlikely(vma == NULL))
2212 return -ENOMEM;
2213
2214 vma->vm_mm = mm;
2215 vma->vm_start = addr;
2216 vma->vm_end = addr + len;
2217
2218 vma->vm_flags = vm_flags | mm->def_flags;
Coly Li3ed75eb2007-10-18 23:39:15 -07002219 vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
Roland McGrathfa5dc222007-02-08 14:20:41 -08002220
2221 vma->vm_ops = &special_mapping_vmops;
2222 vma->vm_private_data = pages;
2223
2224 if (unlikely(insert_vm_struct(mm, vma))) {
2225 kmem_cache_free(vm_area_cachep, vma);
2226 return -ENOMEM;
2227 }
2228
2229 mm->total_vm += len >> PAGE_SHIFT;
2230
2231 return 0;
2232}