Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * mm/mremap.c | |
3 | * | |
4 | * (C) Copyright 1996 Linus Torvalds | |
5 | * | |
046c6884 | 6 | * Address space accounting code <alan@lxorguk.ukuu.org.uk> |
1da177e4 LT |
7 | * (C) Copyright 2002 Red Hat Inc, All Rights Reserved |
8 | */ | |
9 | ||
10 | #include <linux/mm.h> | |
11 | #include <linux/hugetlb.h> | |
1da177e4 | 12 | #include <linux/shm.h> |
1ff82995 | 13 | #include <linux/ksm.h> |
1da177e4 LT |
14 | #include <linux/mman.h> |
15 | #include <linux/swap.h> | |
c59ede7b | 16 | #include <linux/capability.h> |
1da177e4 LT |
17 | #include <linux/fs.h> |
18 | #include <linux/highmem.h> | |
19 | #include <linux/security.h> | |
20 | #include <linux/syscalls.h> | |
cddb8a5c | 21 | #include <linux/mmu_notifier.h> |
1da177e4 LT |
22 | |
23 | #include <asm/uaccess.h> | |
24 | #include <asm/cacheflush.h> | |
25 | #include <asm/tlbflush.h> | |
26 | ||
ba470de4 RR |
27 | #include "internal.h" |
28 | ||
7be7a546 | 29 | static pmd_t *get_old_pmd(struct mm_struct *mm, unsigned long addr) |
1da177e4 LT |
30 | { |
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); | |
37a1c49a | 44 | if (pmd_none(*pmd)) |
1da177e4 LT |
45 | return NULL; |
46 | ||
7be7a546 | 47 | return pmd; |
1da177e4 LT |
48 | } |
49 | ||
8ac1f832 AA |
50 | static pmd_t *alloc_new_pmd(struct mm_struct *mm, struct vm_area_struct *vma, |
51 | unsigned long addr) | |
1da177e4 LT |
52 | { |
53 | pgd_t *pgd; | |
54 | pud_t *pud; | |
c74df32c | 55 | pmd_t *pmd; |
1da177e4 LT |
56 | |
57 | pgd = pgd_offset(mm, addr); | |
1da177e4 LT |
58 | pud = pud_alloc(mm, pgd, addr); |
59 | if (!pud) | |
c74df32c | 60 | return NULL; |
7be7a546 | 61 | |
1da177e4 | 62 | pmd = pmd_alloc(mm, pud, addr); |
7be7a546 | 63 | if (!pmd) |
c74df32c | 64 | return NULL; |
7be7a546 | 65 | |
8ac1f832 | 66 | VM_BUG_ON(pmd_trans_huge(*pmd)); |
c74df32c | 67 | |
7be7a546 | 68 | return pmd; |
1da177e4 LT |
69 | } |
70 | ||
7be7a546 HD |
71 | static void move_ptes(struct vm_area_struct *vma, pmd_t *old_pmd, |
72 | unsigned long old_addr, unsigned long old_end, | |
73 | struct vm_area_struct *new_vma, pmd_t *new_pmd, | |
38a76013 | 74 | unsigned long new_addr, bool need_rmap_locks) |
1da177e4 LT |
75 | { |
76 | struct address_space *mapping = NULL; | |
38a76013 | 77 | struct anon_vma *anon_vma = NULL; |
1da177e4 | 78 | struct mm_struct *mm = vma->vm_mm; |
7be7a546 | 79 | pte_t *old_pte, *new_pte, pte; |
4c21e2f2 | 80 | spinlock_t *old_ptl, *new_ptl; |
1da177e4 | 81 | |
38a76013 ML |
82 | /* |
83 | * When need_rmap_locks is true, we take the i_mmap_mutex and anon_vma | |
84 | * locks to ensure that rmap will always observe either the old or the | |
85 | * new ptes. This is the easiest way to avoid races with | |
86 | * truncate_pagecache(), page migration, etc... | |
87 | * | |
88 | * When need_rmap_locks is false, we use other ways to avoid | |
89 | * such races: | |
90 | * | |
91 | * - During exec() shift_arg_pages(), we use a specially tagged vma | |
92 | * which rmap call sites look for using is_vma_temporary_stack(). | |
93 | * | |
94 | * - During mremap(), new_vma is often known to be placed after vma | |
95 | * in rmap traversal order. This ensures rmap will always observe | |
96 | * either the old pte, or the new pte, or both (the page table locks | |
97 | * serialize access to individual ptes, but only rmap traversal | |
98 | * order guarantees that we won't miss both the old and new ptes). | |
99 | */ | |
100 | if (need_rmap_locks) { | |
101 | if (vma->vm_file) { | |
102 | mapping = vma->vm_file->f_mapping; | |
103 | mutex_lock(&mapping->i_mmap_mutex); | |
104 | } | |
105 | if (vma->anon_vma) { | |
106 | anon_vma = vma->anon_vma; | |
107 | anon_vma_lock(anon_vma); | |
108 | } | |
1da177e4 | 109 | } |
1da177e4 | 110 | |
4c21e2f2 HD |
111 | /* |
112 | * We don't have to worry about the ordering of src and dst | |
113 | * pte locks because exclusive mmap_sem prevents deadlock. | |
114 | */ | |
c74df32c | 115 | old_pte = pte_offset_map_lock(mm, old_pmd, old_addr, &old_ptl); |
ece0e2b6 | 116 | new_pte = pte_offset_map(new_pmd, new_addr); |
4c21e2f2 HD |
117 | new_ptl = pte_lockptr(mm, new_pmd); |
118 | if (new_ptl != old_ptl) | |
f20dc5f7 | 119 | spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); |
6606c3e0 | 120 | arch_enter_lazy_mmu_mode(); |
7be7a546 HD |
121 | |
122 | for (; old_addr < old_end; old_pte++, old_addr += PAGE_SIZE, | |
123 | new_pte++, new_addr += PAGE_SIZE) { | |
124 | if (pte_none(*old_pte)) | |
125 | continue; | |
7b6efc2b | 126 | pte = ptep_get_and_clear(mm, old_addr, old_pte); |
7be7a546 HD |
127 | pte = move_pte(pte, new_vma->vm_page_prot, old_addr, new_addr); |
128 | set_pte_at(mm, new_addr, new_pte, pte); | |
1da177e4 | 129 | } |
7be7a546 | 130 | |
6606c3e0 | 131 | arch_leave_lazy_mmu_mode(); |
4c21e2f2 HD |
132 | if (new_ptl != old_ptl) |
133 | spin_unlock(new_ptl); | |
ece0e2b6 | 134 | pte_unmap(new_pte - 1); |
c74df32c | 135 | pte_unmap_unlock(old_pte - 1, old_ptl); |
108d6642 ML |
136 | if (anon_vma) |
137 | anon_vma_unlock(anon_vma); | |
1da177e4 | 138 | if (mapping) |
3d48ae45 | 139 | mutex_unlock(&mapping->i_mmap_mutex); |
1da177e4 LT |
140 | } |
141 | ||
7be7a546 HD |
142 | #define LATENCY_LIMIT (64 * PAGE_SIZE) |
143 | ||
b6a2fea3 | 144 | unsigned long move_page_tables(struct vm_area_struct *vma, |
1da177e4 | 145 | unsigned long old_addr, struct vm_area_struct *new_vma, |
38a76013 ML |
146 | unsigned long new_addr, unsigned long len, |
147 | bool need_rmap_locks) | |
1da177e4 | 148 | { |
7be7a546 HD |
149 | unsigned long extent, next, old_end; |
150 | pmd_t *old_pmd, *new_pmd; | |
7b6efc2b | 151 | bool need_flush = false; |
1da177e4 | 152 | |
7be7a546 HD |
153 | old_end = old_addr + len; |
154 | flush_cache_range(vma, old_addr, old_end); | |
1da177e4 | 155 | |
7b6efc2b AA |
156 | mmu_notifier_invalidate_range_start(vma->vm_mm, old_addr, old_end); |
157 | ||
7be7a546 | 158 | for (; old_addr < old_end; old_addr += extent, new_addr += extent) { |
1da177e4 | 159 | cond_resched(); |
7be7a546 | 160 | next = (old_addr + PMD_SIZE) & PMD_MASK; |
ebed4846 | 161 | /* even if next overflowed, extent below will be ok */ |
7be7a546 | 162 | extent = next - old_addr; |
ebed4846 AA |
163 | if (extent > old_end - old_addr) |
164 | extent = old_end - old_addr; | |
7be7a546 HD |
165 | old_pmd = get_old_pmd(vma->vm_mm, old_addr); |
166 | if (!old_pmd) | |
167 | continue; | |
8ac1f832 | 168 | new_pmd = alloc_new_pmd(vma->vm_mm, vma, new_addr); |
7be7a546 HD |
169 | if (!new_pmd) |
170 | break; | |
37a1c49a AA |
171 | if (pmd_trans_huge(*old_pmd)) { |
172 | int err = 0; | |
173 | if (extent == HPAGE_PMD_SIZE) | |
174 | err = move_huge_pmd(vma, new_vma, old_addr, | |
175 | new_addr, old_end, | |
176 | old_pmd, new_pmd); | |
177 | if (err > 0) { | |
178 | need_flush = true; | |
179 | continue; | |
180 | } else if (!err) { | |
181 | split_huge_page_pmd(vma->vm_mm, old_pmd); | |
182 | } | |
183 | VM_BUG_ON(pmd_trans_huge(*old_pmd)); | |
184 | } | |
185 | if (pmd_none(*new_pmd) && __pte_alloc(new_vma->vm_mm, new_vma, | |
186 | new_pmd, new_addr)) | |
187 | break; | |
7be7a546 HD |
188 | next = (new_addr + PMD_SIZE) & PMD_MASK; |
189 | if (extent > next - new_addr) | |
190 | extent = next - new_addr; | |
191 | if (extent > LATENCY_LIMIT) | |
192 | extent = LATENCY_LIMIT; | |
193 | move_ptes(vma, old_pmd, old_addr, old_addr + extent, | |
38a76013 | 194 | new_vma, new_pmd, new_addr, need_rmap_locks); |
7b6efc2b | 195 | need_flush = true; |
1da177e4 | 196 | } |
7b6efc2b AA |
197 | if (likely(need_flush)) |
198 | flush_tlb_range(vma, old_end-len, old_addr); | |
199 | ||
200 | mmu_notifier_invalidate_range_end(vma->vm_mm, old_end-len, old_end); | |
7be7a546 HD |
201 | |
202 | return len + old_addr - old_end; /* how much done */ | |
1da177e4 LT |
203 | } |
204 | ||
205 | static unsigned long move_vma(struct vm_area_struct *vma, | |
206 | unsigned long old_addr, unsigned long old_len, | |
207 | unsigned long new_len, unsigned long new_addr) | |
208 | { | |
209 | struct mm_struct *mm = vma->vm_mm; | |
210 | struct vm_area_struct *new_vma; | |
211 | unsigned long vm_flags = vma->vm_flags; | |
212 | unsigned long new_pgoff; | |
213 | unsigned long moved_len; | |
214 | unsigned long excess = 0; | |
365e9c87 | 215 | unsigned long hiwater_vm; |
1da177e4 | 216 | int split = 0; |
7103ad32 | 217 | int err; |
38a76013 | 218 | bool need_rmap_locks; |
1da177e4 LT |
219 | |
220 | /* | |
221 | * We'd prefer to avoid failure later on in do_munmap: | |
222 | * which may split one vma into three before unmapping. | |
223 | */ | |
224 | if (mm->map_count >= sysctl_max_map_count - 3) | |
225 | return -ENOMEM; | |
226 | ||
1ff82995 HD |
227 | /* |
228 | * Advise KSM to break any KSM pages in the area to be moved: | |
229 | * it would be confusing if they were to turn up at the new | |
230 | * location, where they happen to coincide with different KSM | |
231 | * pages recently unmapped. But leave vma->vm_flags as it was, | |
232 | * so KSM can come around to merge on vma and new_vma afterwards. | |
233 | */ | |
7103ad32 HD |
234 | err = ksm_madvise(vma, old_addr, old_addr + old_len, |
235 | MADV_UNMERGEABLE, &vm_flags); | |
236 | if (err) | |
237 | return err; | |
1ff82995 | 238 | |
1da177e4 | 239 | new_pgoff = vma->vm_pgoff + ((old_addr - vma->vm_start) >> PAGE_SHIFT); |
38a76013 ML |
240 | new_vma = copy_vma(&vma, new_addr, new_len, new_pgoff, |
241 | &need_rmap_locks); | |
1da177e4 LT |
242 | if (!new_vma) |
243 | return -ENOMEM; | |
244 | ||
38a76013 ML |
245 | moved_len = move_page_tables(vma, old_addr, new_vma, new_addr, old_len, |
246 | need_rmap_locks); | |
1da177e4 LT |
247 | if (moved_len < old_len) { |
248 | /* | |
249 | * On error, move entries back from new area to old, | |
250 | * which will succeed since page tables still there, | |
251 | * and then proceed to unmap new area instead of old. | |
252 | */ | |
38a76013 ML |
253 | move_page_tables(new_vma, new_addr, vma, old_addr, moved_len, |
254 | true); | |
1da177e4 LT |
255 | vma = new_vma; |
256 | old_len = new_len; | |
257 | old_addr = new_addr; | |
258 | new_addr = -ENOMEM; | |
259 | } | |
260 | ||
261 | /* Conceal VM_ACCOUNT so old reservation is not undone */ | |
262 | if (vm_flags & VM_ACCOUNT) { | |
263 | vma->vm_flags &= ~VM_ACCOUNT; | |
264 | excess = vma->vm_end - vma->vm_start - old_len; | |
265 | if (old_addr > vma->vm_start && | |
266 | old_addr + old_len < vma->vm_end) | |
267 | split = 1; | |
268 | } | |
269 | ||
71799062 | 270 | /* |
365e9c87 HD |
271 | * If we failed to move page tables we still do total_vm increment |
272 | * since do_munmap() will decrement it by old_len == new_len. | |
273 | * | |
274 | * Since total_vm is about to be raised artificially high for a | |
275 | * moment, we need to restore high watermark afterwards: if stats | |
276 | * are taken meanwhile, total_vm and hiwater_vm appear too high. | |
277 | * If this were a serious issue, we'd add a flag to do_munmap(). | |
71799062 | 278 | */ |
365e9c87 | 279 | hiwater_vm = mm->hiwater_vm; |
ab50b8ed | 280 | vm_stat_account(mm, vma->vm_flags, vma->vm_file, new_len>>PAGE_SHIFT); |
71799062 | 281 | |
1da177e4 LT |
282 | if (do_munmap(mm, old_addr, old_len) < 0) { |
283 | /* OOM: unable to split vma, just get accounts right */ | |
284 | vm_unacct_memory(excess >> PAGE_SHIFT); | |
285 | excess = 0; | |
286 | } | |
365e9c87 | 287 | mm->hiwater_vm = hiwater_vm; |
1da177e4 LT |
288 | |
289 | /* Restore VM_ACCOUNT if one or two pieces of vma left */ | |
290 | if (excess) { | |
291 | vma->vm_flags |= VM_ACCOUNT; | |
292 | if (split) | |
293 | vma->vm_next->vm_flags |= VM_ACCOUNT; | |
294 | } | |
295 | ||
1da177e4 LT |
296 | if (vm_flags & VM_LOCKED) { |
297 | mm->locked_vm += new_len >> PAGE_SHIFT; | |
298 | if (new_len > old_len) | |
ba470de4 RR |
299 | mlock_vma_pages_range(new_vma, new_addr + old_len, |
300 | new_addr + new_len); | |
1da177e4 LT |
301 | } |
302 | ||
303 | return new_addr; | |
304 | } | |
305 | ||
54f5de70 AV |
306 | static struct vm_area_struct *vma_to_resize(unsigned long addr, |
307 | unsigned long old_len, unsigned long new_len, unsigned long *p) | |
308 | { | |
309 | struct mm_struct *mm = current->mm; | |
310 | struct vm_area_struct *vma = find_vma(mm, addr); | |
311 | ||
312 | if (!vma || vma->vm_start > addr) | |
313 | goto Efault; | |
314 | ||
315 | if (is_vm_hugetlb_page(vma)) | |
316 | goto Einval; | |
317 | ||
318 | /* We can't remap across vm area boundaries */ | |
319 | if (old_len > vma->vm_end - addr) | |
320 | goto Efault; | |
321 | ||
982134ba LT |
322 | /* Need to be careful about a growing mapping */ |
323 | if (new_len > old_len) { | |
324 | unsigned long pgoff; | |
325 | ||
326 | if (vma->vm_flags & (VM_DONTEXPAND | VM_PFNMAP)) | |
54f5de70 | 327 | goto Efault; |
982134ba LT |
328 | pgoff = (addr - vma->vm_start) >> PAGE_SHIFT; |
329 | pgoff += vma->vm_pgoff; | |
330 | if (pgoff + (new_len >> PAGE_SHIFT) < pgoff) | |
331 | goto Einval; | |
54f5de70 AV |
332 | } |
333 | ||
334 | if (vma->vm_flags & VM_LOCKED) { | |
335 | unsigned long locked, lock_limit; | |
336 | locked = mm->locked_vm << PAGE_SHIFT; | |
59e99e5b | 337 | lock_limit = rlimit(RLIMIT_MEMLOCK); |
54f5de70 AV |
338 | locked += new_len - old_len; |
339 | if (locked > lock_limit && !capable(CAP_IPC_LOCK)) | |
340 | goto Eagain; | |
341 | } | |
342 | ||
343 | if (!may_expand_vm(mm, (new_len - old_len) >> PAGE_SHIFT)) | |
344 | goto Enomem; | |
345 | ||
346 | if (vma->vm_flags & VM_ACCOUNT) { | |
347 | unsigned long charged = (new_len - old_len) >> PAGE_SHIFT; | |
191c5424 | 348 | if (security_vm_enough_memory_mm(mm, charged)) |
54f5de70 AV |
349 | goto Efault; |
350 | *p = charged; | |
351 | } | |
352 | ||
353 | return vma; | |
354 | ||
355 | Efault: /* very odd choice for most of the cases, but... */ | |
356 | return ERR_PTR(-EFAULT); | |
357 | Einval: | |
358 | return ERR_PTR(-EINVAL); | |
359 | Enomem: | |
360 | return ERR_PTR(-ENOMEM); | |
361 | Eagain: | |
362 | return ERR_PTR(-EAGAIN); | |
363 | } | |
364 | ||
ecc1a899 AV |
365 | static unsigned long mremap_to(unsigned long addr, |
366 | unsigned long old_len, unsigned long new_addr, | |
367 | unsigned long new_len) | |
368 | { | |
369 | struct mm_struct *mm = current->mm; | |
370 | struct vm_area_struct *vma; | |
371 | unsigned long ret = -EINVAL; | |
372 | unsigned long charged = 0; | |
097eed10 | 373 | unsigned long map_flags; |
ecc1a899 AV |
374 | |
375 | if (new_addr & ~PAGE_MASK) | |
376 | goto out; | |
377 | ||
378 | if (new_len > TASK_SIZE || new_addr > TASK_SIZE - new_len) | |
379 | goto out; | |
380 | ||
381 | /* Check if the location we're moving into overlaps the | |
382 | * old location at all, and fail if it does. | |
383 | */ | |
384 | if ((new_addr <= addr) && (new_addr+new_len) > addr) | |
385 | goto out; | |
386 | ||
387 | if ((addr <= new_addr) && (addr+old_len) > new_addr) | |
388 | goto out; | |
389 | ||
ecc1a899 AV |
390 | ret = do_munmap(mm, new_addr, new_len); |
391 | if (ret) | |
392 | goto out; | |
393 | ||
394 | if (old_len >= new_len) { | |
395 | ret = do_munmap(mm, addr+new_len, old_len - new_len); | |
396 | if (ret && old_len != new_len) | |
397 | goto out; | |
398 | old_len = new_len; | |
399 | } | |
400 | ||
401 | vma = vma_to_resize(addr, old_len, new_len, &charged); | |
402 | if (IS_ERR(vma)) { | |
403 | ret = PTR_ERR(vma); | |
404 | goto out; | |
405 | } | |
406 | ||
097eed10 AV |
407 | map_flags = MAP_FIXED; |
408 | if (vma->vm_flags & VM_MAYSHARE) | |
409 | map_flags |= MAP_SHARED; | |
9206de95 | 410 | |
097eed10 AV |
411 | ret = get_unmapped_area(vma->vm_file, new_addr, new_len, vma->vm_pgoff + |
412 | ((addr - vma->vm_start) >> PAGE_SHIFT), | |
413 | map_flags); | |
ecc1a899 | 414 | if (ret & ~PAGE_MASK) |
097eed10 AV |
415 | goto out1; |
416 | ||
417 | ret = move_vma(vma, addr, old_len, new_len, new_addr); | |
418 | if (!(ret & ~PAGE_MASK)) | |
419 | goto out; | |
420 | out1: | |
421 | vm_unacct_memory(charged); | |
ecc1a899 AV |
422 | |
423 | out: | |
424 | return ret; | |
425 | } | |
426 | ||
1a0ef85f AV |
427 | static int vma_expandable(struct vm_area_struct *vma, unsigned long delta) |
428 | { | |
f106af4e | 429 | unsigned long end = vma->vm_end + delta; |
9206de95 | 430 | if (end < vma->vm_end) /* overflow */ |
f106af4e | 431 | return 0; |
9206de95 | 432 | if (vma->vm_next && vma->vm_next->vm_start < end) /* intersection */ |
f106af4e AV |
433 | return 0; |
434 | if (get_unmapped_area(NULL, vma->vm_start, end - vma->vm_start, | |
435 | 0, MAP_FIXED) & ~PAGE_MASK) | |
1a0ef85f | 436 | return 0; |
1a0ef85f AV |
437 | return 1; |
438 | } | |
439 | ||
1da177e4 LT |
440 | /* |
441 | * Expand (or shrink) an existing mapping, potentially moving it at the | |
442 | * same time (controlled by the MREMAP_MAYMOVE flag and available VM space) | |
443 | * | |
444 | * MREMAP_FIXED option added 5-Dec-1999 by Benjamin LaHaise | |
445 | * This option implies MREMAP_MAYMOVE. | |
446 | */ | |
63a81db1 AV |
447 | SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len, |
448 | unsigned long, new_len, unsigned long, flags, | |
449 | unsigned long, new_addr) | |
1da177e4 | 450 | { |
d0de32d9 | 451 | struct mm_struct *mm = current->mm; |
1da177e4 LT |
452 | struct vm_area_struct *vma; |
453 | unsigned long ret = -EINVAL; | |
454 | unsigned long charged = 0; | |
455 | ||
63a81db1 AV |
456 | down_write(¤t->mm->mmap_sem); |
457 | ||
1da177e4 LT |
458 | if (flags & ~(MREMAP_FIXED | MREMAP_MAYMOVE)) |
459 | goto out; | |
460 | ||
461 | if (addr & ~PAGE_MASK) | |
462 | goto out; | |
463 | ||
464 | old_len = PAGE_ALIGN(old_len); | |
465 | new_len = PAGE_ALIGN(new_len); | |
466 | ||
467 | /* | |
468 | * We allow a zero old-len as a special case | |
469 | * for DOS-emu "duplicate shm area" thing. But | |
470 | * a zero new-len is nonsensical. | |
471 | */ | |
472 | if (!new_len) | |
473 | goto out; | |
474 | ||
1da177e4 | 475 | if (flags & MREMAP_FIXED) { |
ecc1a899 AV |
476 | if (flags & MREMAP_MAYMOVE) |
477 | ret = mremap_to(addr, old_len, new_addr, new_len); | |
478 | goto out; | |
1da177e4 LT |
479 | } |
480 | ||
481 | /* | |
482 | * Always allow a shrinking remap: that just unmaps | |
483 | * the unnecessary pages.. | |
484 | * do_munmap does all the needed commit accounting | |
485 | */ | |
486 | if (old_len >= new_len) { | |
d0de32d9 | 487 | ret = do_munmap(mm, addr+new_len, old_len - new_len); |
1da177e4 LT |
488 | if (ret && old_len != new_len) |
489 | goto out; | |
490 | ret = addr; | |
ecc1a899 | 491 | goto out; |
1da177e4 LT |
492 | } |
493 | ||
494 | /* | |
ecc1a899 | 495 | * Ok, we need to grow.. |
1da177e4 | 496 | */ |
54f5de70 AV |
497 | vma = vma_to_resize(addr, old_len, new_len, &charged); |
498 | if (IS_ERR(vma)) { | |
499 | ret = PTR_ERR(vma); | |
1da177e4 | 500 | goto out; |
119f657c | 501 | } |
1da177e4 | 502 | |
1da177e4 | 503 | /* old_len exactly to the end of the area.. |
1da177e4 | 504 | */ |
ecc1a899 | 505 | if (old_len == vma->vm_end - addr) { |
1da177e4 | 506 | /* can we just expand the current mapping? */ |
1a0ef85f | 507 | if (vma_expandable(vma, new_len - old_len)) { |
1da177e4 LT |
508 | int pages = (new_len - old_len) >> PAGE_SHIFT; |
509 | ||
5beb4930 RR |
510 | if (vma_adjust(vma, vma->vm_start, addr + new_len, |
511 | vma->vm_pgoff, NULL)) { | |
512 | ret = -ENOMEM; | |
513 | goto out; | |
514 | } | |
1da177e4 | 515 | |
d0de32d9 | 516 | vm_stat_account(mm, vma->vm_flags, vma->vm_file, pages); |
1da177e4 | 517 | if (vma->vm_flags & VM_LOCKED) { |
d0de32d9 | 518 | mm->locked_vm += pages; |
ba470de4 | 519 | mlock_vma_pages_range(vma, addr + old_len, |
1da177e4 LT |
520 | addr + new_len); |
521 | } | |
522 | ret = addr; | |
523 | goto out; | |
524 | } | |
525 | } | |
526 | ||
527 | /* | |
528 | * We weren't able to just expand or shrink the area, | |
529 | * we need to create a new one and move it.. | |
530 | */ | |
531 | ret = -ENOMEM; | |
532 | if (flags & MREMAP_MAYMOVE) { | |
ecc1a899 AV |
533 | unsigned long map_flags = 0; |
534 | if (vma->vm_flags & VM_MAYSHARE) | |
535 | map_flags |= MAP_SHARED; | |
536 | ||
537 | new_addr = get_unmapped_area(vma->vm_file, 0, new_len, | |
93587414 AV |
538 | vma->vm_pgoff + |
539 | ((addr - vma->vm_start) >> PAGE_SHIFT), | |
540 | map_flags); | |
ecc1a899 AV |
541 | if (new_addr & ~PAGE_MASK) { |
542 | ret = new_addr; | |
543 | goto out; | |
1da177e4 | 544 | } |
ecc1a899 | 545 | |
1da177e4 LT |
546 | ret = move_vma(vma, addr, old_len, new_len, new_addr); |
547 | } | |
548 | out: | |
549 | if (ret & ~PAGE_MASK) | |
550 | vm_unacct_memory(charged); | |
1da177e4 LT |
551 | up_write(¤t->mm->mmap_sem); |
552 | return ret; | |
553 | } |