blob: a7c1f9f9b94157033e232ef2618ebb67e0eef99d [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * mm/mremap.c
3 *
4 * (C) Copyright 1996 Linus Torvalds
5 *
Alan Cox046c6882009-01-05 14:06:29 +00006 * Address space accounting code <alan@lxorguk.ukuu.org.uk>
Linus Torvalds1da177e2005-04-16 15:20:36 -07007 * (C) Copyright 2002 Red Hat Inc, All Rights Reserved
8 */
9
10#include <linux/mm.h>
11#include <linux/hugetlb.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <linux/shm.h>
Hugh Dickins1ff82992009-09-21 17:02:05 -070013#include <linux/ksm.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070014#include <linux/mman.h>
15#include <linux/swap.h>
Randy.Dunlapc59ede72006-01-11 12:17:46 -080016#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include <linux/fs.h>
18#include <linux/highmem.h>
19#include <linux/security.h>
20#include <linux/syscalls.h>
Andrea Arcangelicddb8a52008-07-28 15:46:29 -070021#include <linux/mmu_notifier.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022
23#include <asm/uaccess.h>
24#include <asm/cacheflush.h>
25#include <asm/tlbflush.h>
26
Rik van Rielba470de2008-10-18 20:26:50 -070027#include "internal.h"
28
Hugh Dickins7be7a542005-10-29 18:16:00 -070029static pmd_t *get_old_pmd(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -070030{
31 pgd_t *pgd;
32 pud_t *pud;
33 pmd_t *pmd;
34
35 pgd = pgd_offset(mm, addr);
36 if (pgd_none_or_clear_bad(pgd))
37 return NULL;
38
39 pud = pud_offset(pgd, addr);
40 if (pud_none_or_clear_bad(pud))
41 return NULL;
42
43 pmd = pmd_offset(pud, addr);
Andrea Arcangelibae9c192011-01-13 15:46:46 -080044 split_huge_page_pmd(mm, pmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -070045 if (pmd_none_or_clear_bad(pmd))
46 return NULL;
47
Hugh Dickins7be7a542005-10-29 18:16:00 -070048 return pmd;
Linus Torvalds1da177e2005-04-16 15:20:36 -070049}
50
Andrea Arcangeli8ac1f832011-01-13 15:46:43 -080051static pmd_t *alloc_new_pmd(struct mm_struct *mm, struct vm_area_struct *vma,
52 unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -070053{
54 pgd_t *pgd;
55 pud_t *pud;
Hugh Dickinsc74df322005-10-29 18:16:23 -070056 pmd_t *pmd;
Linus Torvalds1da177e2005-04-16 15:20:36 -070057
58 pgd = pgd_offset(mm, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -070059 pud = pud_alloc(mm, pgd, addr);
60 if (!pud)
Hugh Dickinsc74df322005-10-29 18:16:23 -070061 return NULL;
Hugh Dickins7be7a542005-10-29 18:16:00 -070062
Linus Torvalds1da177e2005-04-16 15:20:36 -070063 pmd = pmd_alloc(mm, pud, addr);
Hugh Dickins7be7a542005-10-29 18:16:00 -070064 if (!pmd)
Hugh Dickinsc74df322005-10-29 18:16:23 -070065 return NULL;
Hugh Dickins7be7a542005-10-29 18:16:00 -070066
Andrea Arcangeli8ac1f832011-01-13 15:46:43 -080067 VM_BUG_ON(pmd_trans_huge(*pmd));
68 if (pmd_none(*pmd) && __pte_alloc(mm, vma, pmd, addr))
Hugh Dickinsc74df322005-10-29 18:16:23 -070069 return NULL;
70
Hugh Dickins7be7a542005-10-29 18:16:00 -070071 return pmd;
Linus Torvalds1da177e2005-04-16 15:20:36 -070072}
73
Hugh Dickins7be7a542005-10-29 18:16:00 -070074static void move_ptes(struct vm_area_struct *vma, pmd_t *old_pmd,
75 unsigned long old_addr, unsigned long old_end,
76 struct vm_area_struct *new_vma, pmd_t *new_pmd,
77 unsigned long new_addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -070078{
79 struct address_space *mapping = NULL;
80 struct mm_struct *mm = vma->vm_mm;
Hugh Dickins7be7a542005-10-29 18:16:00 -070081 pte_t *old_pte, *new_pte, pte;
Hugh Dickins4c21e2f2005-10-29 18:16:40 -070082 spinlock_t *old_ptl, *new_ptl;
Andrea Arcangelicddb8a52008-07-28 15:46:29 -070083 unsigned long old_start;
Linus Torvalds1da177e2005-04-16 15:20:36 -070084
Andrea Arcangelicddb8a52008-07-28 15:46:29 -070085 old_start = old_addr;
86 mmu_notifier_invalidate_range_start(vma->vm_mm,
87 old_start, old_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -070088 if (vma->vm_file) {
89 /*
90 * Subtle point from Rajesh Venkatasubramanian: before
npiggin@suse.de25d9e2d2009-08-21 02:35:05 +100091 * moving file-based ptes, we must lock truncate_pagecache
92 * out, since it might clean the dst vma before the src vma,
Linus Torvalds1da177e2005-04-16 15:20:36 -070093 * and we propagate stale pages into the dst afterward.
94 */
95 mapping = vma->vm_file->f_mapping;
96 spin_lock(&mapping->i_mmap_lock);
Hugh Dickinsa3e8cc62011-02-23 21:39:49 -080097 new_vma->vm_truncate_count = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070098 }
Hugh Dickins7be7a542005-10-29 18:16:00 -070099
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700100 /*
101 * We don't have to worry about the ordering of src and dst
102 * pte locks because exclusive mmap_sem prevents deadlock.
103 */
Hugh Dickinsc74df322005-10-29 18:16:23 -0700104 old_pte = pte_offset_map_lock(mm, old_pmd, old_addr, &old_ptl);
Peter Zijlstraece0e2b2010-10-26 14:21:52 -0700105 new_pte = pte_offset_map(new_pmd, new_addr);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700106 new_ptl = pte_lockptr(mm, new_pmd);
107 if (new_ptl != old_ptl)
Ingo Molnarf20dc5f2006-07-03 00:25:08 -0700108 spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING);
Zachary Amsden6606c3e2006-09-30 23:29:33 -0700109 arch_enter_lazy_mmu_mode();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110
Hugh Dickins7be7a542005-10-29 18:16:00 -0700111 for (; old_addr < old_end; old_pte++, old_addr += PAGE_SIZE,
112 new_pte++, new_addr += PAGE_SIZE) {
113 if (pte_none(*old_pte))
114 continue;
115 pte = ptep_clear_flush(vma, old_addr, old_pte);
Hugh Dickins7be7a542005-10-29 18:16:00 -0700116 pte = move_pte(pte, new_vma->vm_page_prot, old_addr, new_addr);
117 set_pte_at(mm, new_addr, new_pte, pte);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118 }
Hugh Dickins7be7a542005-10-29 18:16:00 -0700119
Zachary Amsden6606c3e2006-09-30 23:29:33 -0700120 arch_leave_lazy_mmu_mode();
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700121 if (new_ptl != old_ptl)
122 spin_unlock(new_ptl);
Peter Zijlstraece0e2b2010-10-26 14:21:52 -0700123 pte_unmap(new_pte - 1);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700124 pte_unmap_unlock(old_pte - 1, old_ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125 if (mapping)
126 spin_unlock(&mapping->i_mmap_lock);
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700127 mmu_notifier_invalidate_range_end(vma->vm_mm, old_start, old_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128}
129
Hugh Dickins7be7a542005-10-29 18:16:00 -0700130#define LATENCY_LIMIT (64 * PAGE_SIZE)
131
Ollie Wildb6a2fea2007-07-19 01:48:16 -0700132unsigned long move_page_tables(struct vm_area_struct *vma,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 unsigned long old_addr, struct vm_area_struct *new_vma,
134 unsigned long new_addr, unsigned long len)
135{
Hugh Dickins7be7a542005-10-29 18:16:00 -0700136 unsigned long extent, next, old_end;
137 pmd_t *old_pmd, *new_pmd;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138
Hugh Dickins7be7a542005-10-29 18:16:00 -0700139 old_end = old_addr + len;
140 flush_cache_range(vma, old_addr, old_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141
Hugh Dickins7be7a542005-10-29 18:16:00 -0700142 for (; old_addr < old_end; old_addr += extent, new_addr += extent) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143 cond_resched();
Hugh Dickins7be7a542005-10-29 18:16:00 -0700144 next = (old_addr + PMD_SIZE) & PMD_MASK;
145 if (next - 1 > old_end)
146 next = old_end;
147 extent = next - old_addr;
148 old_pmd = get_old_pmd(vma->vm_mm, old_addr);
149 if (!old_pmd)
150 continue;
Andrea Arcangeli8ac1f832011-01-13 15:46:43 -0800151 new_pmd = alloc_new_pmd(vma->vm_mm, vma, new_addr);
Hugh Dickins7be7a542005-10-29 18:16:00 -0700152 if (!new_pmd)
153 break;
154 next = (new_addr + PMD_SIZE) & PMD_MASK;
155 if (extent > next - new_addr)
156 extent = next - new_addr;
157 if (extent > LATENCY_LIMIT)
158 extent = LATENCY_LIMIT;
159 move_ptes(vma, old_pmd, old_addr, old_addr + extent,
160 new_vma, new_pmd, new_addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161 }
Hugh Dickins7be7a542005-10-29 18:16:00 -0700162
163 return len + old_addr - old_end; /* how much done */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164}
165
166static unsigned long move_vma(struct vm_area_struct *vma,
167 unsigned long old_addr, unsigned long old_len,
168 unsigned long new_len, unsigned long new_addr)
169{
170 struct mm_struct *mm = vma->vm_mm;
171 struct vm_area_struct *new_vma;
172 unsigned long vm_flags = vma->vm_flags;
173 unsigned long new_pgoff;
174 unsigned long moved_len;
175 unsigned long excess = 0;
Hugh Dickins365e9c872005-10-29 18:16:18 -0700176 unsigned long hiwater_vm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177 int split = 0;
Hugh Dickins7103ad32009-09-21 17:02:28 -0700178 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179
180 /*
181 * We'd prefer to avoid failure later on in do_munmap:
182 * which may split one vma into three before unmapping.
183 */
184 if (mm->map_count >= sysctl_max_map_count - 3)
185 return -ENOMEM;
186
Hugh Dickins1ff82992009-09-21 17:02:05 -0700187 /*
188 * Advise KSM to break any KSM pages in the area to be moved:
189 * it would be confusing if they were to turn up at the new
190 * location, where they happen to coincide with different KSM
191 * pages recently unmapped. But leave vma->vm_flags as it was,
192 * so KSM can come around to merge on vma and new_vma afterwards.
193 */
Hugh Dickins7103ad32009-09-21 17:02:28 -0700194 err = ksm_madvise(vma, old_addr, old_addr + old_len,
195 MADV_UNMERGEABLE, &vm_flags);
196 if (err)
197 return err;
Hugh Dickins1ff82992009-09-21 17:02:05 -0700198
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199 new_pgoff = vma->vm_pgoff + ((old_addr - vma->vm_start) >> PAGE_SHIFT);
200 new_vma = copy_vma(&vma, new_addr, new_len, new_pgoff);
201 if (!new_vma)
202 return -ENOMEM;
203
204 moved_len = move_page_tables(vma, old_addr, new_vma, new_addr, old_len);
205 if (moved_len < old_len) {
206 /*
207 * On error, move entries back from new area to old,
208 * which will succeed since page tables still there,
209 * and then proceed to unmap new area instead of old.
210 */
211 move_page_tables(new_vma, new_addr, vma, old_addr, moved_len);
212 vma = new_vma;
213 old_len = new_len;
214 old_addr = new_addr;
215 new_addr = -ENOMEM;
216 }
217
218 /* Conceal VM_ACCOUNT so old reservation is not undone */
219 if (vm_flags & VM_ACCOUNT) {
220 vma->vm_flags &= ~VM_ACCOUNT;
221 excess = vma->vm_end - vma->vm_start - old_len;
222 if (old_addr > vma->vm_start &&
223 old_addr + old_len < vma->vm_end)
224 split = 1;
225 }
226
Kirill Korotaev71799062005-05-16 21:53:18 -0700227 /*
Hugh Dickins365e9c872005-10-29 18:16:18 -0700228 * If we failed to move page tables we still do total_vm increment
229 * since do_munmap() will decrement it by old_len == new_len.
230 *
231 * Since total_vm is about to be raised artificially high for a
232 * moment, we need to restore high watermark afterwards: if stats
233 * are taken meanwhile, total_vm and hiwater_vm appear too high.
234 * If this were a serious issue, we'd add a flag to do_munmap().
Kirill Korotaev71799062005-05-16 21:53:18 -0700235 */
Hugh Dickins365e9c872005-10-29 18:16:18 -0700236 hiwater_vm = mm->hiwater_vm;
Kirill Korotaev71799062005-05-16 21:53:18 -0700237 mm->total_vm += new_len >> PAGE_SHIFT;
Hugh Dickinsab50b8e2005-10-29 18:15:56 -0700238 vm_stat_account(mm, vma->vm_flags, vma->vm_file, new_len>>PAGE_SHIFT);
Kirill Korotaev71799062005-05-16 21:53:18 -0700239
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240 if (do_munmap(mm, old_addr, old_len) < 0) {
241 /* OOM: unable to split vma, just get accounts right */
242 vm_unacct_memory(excess >> PAGE_SHIFT);
243 excess = 0;
244 }
Hugh Dickins365e9c872005-10-29 18:16:18 -0700245 mm->hiwater_vm = hiwater_vm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246
247 /* Restore VM_ACCOUNT if one or two pieces of vma left */
248 if (excess) {
249 vma->vm_flags |= VM_ACCOUNT;
250 if (split)
251 vma->vm_next->vm_flags |= VM_ACCOUNT;
252 }
253
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254 if (vm_flags & VM_LOCKED) {
255 mm->locked_vm += new_len >> PAGE_SHIFT;
256 if (new_len > old_len)
Rik van Rielba470de2008-10-18 20:26:50 -0700257 mlock_vma_pages_range(new_vma, new_addr + old_len,
258 new_addr + new_len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 }
260
261 return new_addr;
262}
263
Al Viro54f5de72009-11-24 07:17:46 -0500264static struct vm_area_struct *vma_to_resize(unsigned long addr,
265 unsigned long old_len, unsigned long new_len, unsigned long *p)
266{
267 struct mm_struct *mm = current->mm;
268 struct vm_area_struct *vma = find_vma(mm, addr);
269
270 if (!vma || vma->vm_start > addr)
271 goto Efault;
272
273 if (is_vm_hugetlb_page(vma))
274 goto Einval;
275
276 /* We can't remap across vm area boundaries */
277 if (old_len > vma->vm_end - addr)
278 goto Efault;
279
Linus Torvalds982134b2011-04-07 07:35:50 -0700280 /* Need to be careful about a growing mapping */
281 if (new_len > old_len) {
282 unsigned long pgoff;
283
284 if (vma->vm_flags & (VM_DONTEXPAND | VM_PFNMAP))
Al Viro54f5de72009-11-24 07:17:46 -0500285 goto Efault;
Linus Torvalds982134b2011-04-07 07:35:50 -0700286 pgoff = (addr - vma->vm_start) >> PAGE_SHIFT;
287 pgoff += vma->vm_pgoff;
288 if (pgoff + (new_len >> PAGE_SHIFT) < pgoff)
289 goto Einval;
Al Viro54f5de72009-11-24 07:17:46 -0500290 }
291
292 if (vma->vm_flags & VM_LOCKED) {
293 unsigned long locked, lock_limit;
294 locked = mm->locked_vm << PAGE_SHIFT;
Jiri Slaby59e99e52010-03-05 13:41:44 -0800295 lock_limit = rlimit(RLIMIT_MEMLOCK);
Al Viro54f5de72009-11-24 07:17:46 -0500296 locked += new_len - old_len;
297 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
298 goto Eagain;
299 }
300
301 if (!may_expand_vm(mm, (new_len - old_len) >> PAGE_SHIFT))
302 goto Enomem;
303
304 if (vma->vm_flags & VM_ACCOUNT) {
305 unsigned long charged = (new_len - old_len) >> PAGE_SHIFT;
306 if (security_vm_enough_memory(charged))
307 goto Efault;
308 *p = charged;
309 }
310
311 return vma;
312
313Efault: /* very odd choice for most of the cases, but... */
314 return ERR_PTR(-EFAULT);
315Einval:
316 return ERR_PTR(-EINVAL);
317Enomem:
318 return ERR_PTR(-ENOMEM);
319Eagain:
320 return ERR_PTR(-EAGAIN);
321}
322
Al Viroecc1a892009-11-24 07:28:07 -0500323static unsigned long mremap_to(unsigned long addr,
324 unsigned long old_len, unsigned long new_addr,
325 unsigned long new_len)
326{
327 struct mm_struct *mm = current->mm;
328 struct vm_area_struct *vma;
329 unsigned long ret = -EINVAL;
330 unsigned long charged = 0;
Al Viro097eed12009-11-24 08:43:52 -0500331 unsigned long map_flags;
Al Viroecc1a892009-11-24 07:28:07 -0500332
333 if (new_addr & ~PAGE_MASK)
334 goto out;
335
336 if (new_len > TASK_SIZE || new_addr > TASK_SIZE - new_len)
337 goto out;
338
339 /* Check if the location we're moving into overlaps the
340 * old location at all, and fail if it does.
341 */
342 if ((new_addr <= addr) && (new_addr+new_len) > addr)
343 goto out;
344
345 if ((addr <= new_addr) && (addr+old_len) > new_addr)
346 goto out;
347
348 ret = security_file_mmap(NULL, 0, 0, 0, new_addr, 1);
349 if (ret)
350 goto out;
351
352 ret = do_munmap(mm, new_addr, new_len);
353 if (ret)
354 goto out;
355
356 if (old_len >= new_len) {
357 ret = do_munmap(mm, addr+new_len, old_len - new_len);
358 if (ret && old_len != new_len)
359 goto out;
360 old_len = new_len;
361 }
362
363 vma = vma_to_resize(addr, old_len, new_len, &charged);
364 if (IS_ERR(vma)) {
365 ret = PTR_ERR(vma);
366 goto out;
367 }
368
Al Viro097eed12009-11-24 08:43:52 -0500369 map_flags = MAP_FIXED;
370 if (vma->vm_flags & VM_MAYSHARE)
371 map_flags |= MAP_SHARED;
Al Viro9206de92009-12-03 15:23:11 -0500372
Al Viro097eed12009-11-24 08:43:52 -0500373 ret = get_unmapped_area(vma->vm_file, new_addr, new_len, vma->vm_pgoff +
374 ((addr - vma->vm_start) >> PAGE_SHIFT),
375 map_flags);
Al Viroecc1a892009-11-24 07:28:07 -0500376 if (ret & ~PAGE_MASK)
Al Viro097eed12009-11-24 08:43:52 -0500377 goto out1;
378
379 ret = move_vma(vma, addr, old_len, new_len, new_addr);
380 if (!(ret & ~PAGE_MASK))
381 goto out;
382out1:
383 vm_unacct_memory(charged);
Al Viroecc1a892009-11-24 07:28:07 -0500384
385out:
386 return ret;
387}
388
Al Viro1a0ef852009-11-24 07:43:18 -0500389static int vma_expandable(struct vm_area_struct *vma, unsigned long delta)
390{
Al Virof106af42009-11-24 08:25:18 -0500391 unsigned long end = vma->vm_end + delta;
Al Viro9206de92009-12-03 15:23:11 -0500392 if (end < vma->vm_end) /* overflow */
Al Viro1a0ef852009-11-24 07:43:18 -0500393 return 0;
Al Viro9206de92009-12-03 15:23:11 -0500394 if (vma->vm_next && vma->vm_next->vm_start < end) /* intersection */
Al Virof106af42009-11-24 08:25:18 -0500395 return 0;
396 if (get_unmapped_area(NULL, vma->vm_start, end - vma->vm_start,
397 0, MAP_FIXED) & ~PAGE_MASK)
398 return 0;
Al Viro1a0ef852009-11-24 07:43:18 -0500399 return 1;
400}
401
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402/*
403 * Expand (or shrink) an existing mapping, potentially moving it at the
404 * same time (controlled by the MREMAP_MAYMOVE flag and available VM space)
405 *
406 * MREMAP_FIXED option added 5-Dec-1999 by Benjamin LaHaise
407 * This option implies MREMAP_MAYMOVE.
408 */
409unsigned long do_mremap(unsigned long addr,
410 unsigned long old_len, unsigned long new_len,
411 unsigned long flags, unsigned long new_addr)
412{
Hugh Dickinsd0de32d2005-10-29 18:16:16 -0700413 struct mm_struct *mm = current->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414 struct vm_area_struct *vma;
415 unsigned long ret = -EINVAL;
416 unsigned long charged = 0;
417
418 if (flags & ~(MREMAP_FIXED | MREMAP_MAYMOVE))
419 goto out;
420
421 if (addr & ~PAGE_MASK)
422 goto out;
423
424 old_len = PAGE_ALIGN(old_len);
425 new_len = PAGE_ALIGN(new_len);
426
427 /*
428 * We allow a zero old-len as a special case
429 * for DOS-emu "duplicate shm area" thing. But
430 * a zero new-len is nonsensical.
431 */
432 if (!new_len)
433 goto out;
434
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435 if (flags & MREMAP_FIXED) {
Al Viroecc1a892009-11-24 07:28:07 -0500436 if (flags & MREMAP_MAYMOVE)
437 ret = mremap_to(addr, old_len, new_addr, new_len);
438 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700439 }
440
441 /*
442 * Always allow a shrinking remap: that just unmaps
443 * the unnecessary pages..
444 * do_munmap does all the needed commit accounting
445 */
446 if (old_len >= new_len) {
Hugh Dickinsd0de32d2005-10-29 18:16:16 -0700447 ret = do_munmap(mm, addr+new_len, old_len - new_len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448 if (ret && old_len != new_len)
449 goto out;
450 ret = addr;
Al Viroecc1a892009-11-24 07:28:07 -0500451 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700452 }
453
454 /*
Al Viroecc1a892009-11-24 07:28:07 -0500455 * Ok, we need to grow..
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456 */
Al Viro54f5de72009-11-24 07:17:46 -0500457 vma = vma_to_resize(addr, old_len, new_len, &charged);
458 if (IS_ERR(vma)) {
459 ret = PTR_ERR(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700460 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461 }
462
463 /* old_len exactly to the end of the area..
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464 */
Al Viroecc1a892009-11-24 07:28:07 -0500465 if (old_len == vma->vm_end - addr) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466 /* can we just expand the current mapping? */
Al Viro1a0ef852009-11-24 07:43:18 -0500467 if (vma_expandable(vma, new_len - old_len)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700468 int pages = (new_len - old_len) >> PAGE_SHIFT;
469
Rik van Riel5beb4932010-03-05 13:42:07 -0800470 if (vma_adjust(vma, vma->vm_start, addr + new_len,
471 vma->vm_pgoff, NULL)) {
472 ret = -ENOMEM;
473 goto out;
474 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475
Hugh Dickinsd0de32d2005-10-29 18:16:16 -0700476 mm->total_vm += pages;
477 vm_stat_account(mm, vma->vm_flags, vma->vm_file, pages);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478 if (vma->vm_flags & VM_LOCKED) {
Hugh Dickinsd0de32d2005-10-29 18:16:16 -0700479 mm->locked_vm += pages;
Rik van Rielba470de2008-10-18 20:26:50 -0700480 mlock_vma_pages_range(vma, addr + old_len,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481 addr + new_len);
482 }
483 ret = addr;
484 goto out;
485 }
486 }
487
488 /*
489 * We weren't able to just expand or shrink the area,
490 * we need to create a new one and move it..
491 */
492 ret = -ENOMEM;
493 if (flags & MREMAP_MAYMOVE) {
Al Viroecc1a892009-11-24 07:28:07 -0500494 unsigned long map_flags = 0;
495 if (vma->vm_flags & VM_MAYSHARE)
496 map_flags |= MAP_SHARED;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497
Al Viroecc1a892009-11-24 07:28:07 -0500498 new_addr = get_unmapped_area(vma->vm_file, 0, new_len,
Al Viro93587412009-11-24 08:45:24 -0500499 vma->vm_pgoff +
500 ((addr - vma->vm_start) >> PAGE_SHIFT),
501 map_flags);
Al Viroecc1a892009-11-24 07:28:07 -0500502 if (new_addr & ~PAGE_MASK) {
503 ret = new_addr;
504 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505 }
Al Viroecc1a892009-11-24 07:28:07 -0500506
507 ret = security_file_mmap(NULL, 0, 0, 0, new_addr, 1);
508 if (ret)
509 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510 ret = move_vma(vma, addr, old_len, new_len, new_addr);
511 }
512out:
513 if (ret & ~PAGE_MASK)
514 vm_unacct_memory(charged);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515 return ret;
516}
517
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100518SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
519 unsigned long, new_len, unsigned long, flags,
520 unsigned long, new_addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700521{
522 unsigned long ret;
523
524 down_write(&current->mm->mmap_sem);
525 ret = do_mremap(addr, old_len, new_len, flags, new_addr);
526 up_write(&current->mm->mmap_sem);
527 return ret;
528}