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1da177e Linux-2.6.12-rc2
Linus Torvalds authored
1 /*
2 * mm/mremap.c
3 *
4 * (C) Copyright 1996 Linus Torvalds
5 *
046c688 @Alan-Cox mm: update my address
Alan-Cox authored
6 * Address space accounting code <alan@lxorguk.ukuu.org.uk>
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
7 * (C) Copyright 2002 Red Hat Inc, All Rights Reserved
8 */
9
10 #include <linux/mm.h>
11 #include <linux/hugetlb.h>
12 #include <linux/shm.h>
1ff8299 ksm: prevent mremap move poisoning
Hugh Dickins authored
13 #include <linux/ksm.h>
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
14 #include <linux/mman.h>
15 #include <linux/swap.h>
c59ede7 [PATCH] move capable() to capability.h
Randy.Dunlap authored
16 #include <linux/capability.h>
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
17 #include <linux/fs.h>
18 #include <linux/highmem.h>
19 #include <linux/security.h>
20 #include <linux/syscalls.h>
cddb8a5 mmu-notifiers: core
Andrea Arcangeli authored
21 #include <linux/mmu_notifier.h>
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
22
23 #include <asm/uaccess.h>
24 #include <asm/cacheflush.h>
25 #include <asm/tlbflush.h>
26
ba470de mmap: handle mlocked pages during map, remap, unmap
Rik van Riel authored
27 #include "internal.h"
28
7be7a54 [PATCH] mm: move_page_tables by extents
Hugh Dickins authored
29 static pmd_t *get_old_pmd(struct mm_struct *mm, unsigned long addr)
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
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);
37a1c49 thp: mremap support and TLB optimization
Andrea Arcangeli authored
44 if (pmd_none(*pmd))
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
45 return NULL;
46
7be7a54 [PATCH] mm: move_page_tables by extents
Hugh Dickins authored
47 return pmd;
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
48 }
49
8ac1f83 thp: pte alloc trans splitting
Andrea Arcangeli authored
50 static pmd_t *alloc_new_pmd(struct mm_struct *mm, struct vm_area_struct *vma,
51 unsigned long addr)
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
52 {
53 pgd_t *pgd;
54 pud_t *pud;
c74df32 [PATCH] mm: ptd_alloc take ptlock
Hugh Dickins authored
55 pmd_t *pmd;
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
56
57 pgd = pgd_offset(mm, addr);
58 pud = pud_alloc(mm, pgd, addr);
59 if (!pud)
c74df32 [PATCH] mm: ptd_alloc take ptlock
Hugh Dickins authored
60 return NULL;
7be7a54 [PATCH] mm: move_page_tables by extents
Hugh Dickins authored
61
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
62 pmd = pmd_alloc(mm, pud, addr);
7be7a54 [PATCH] mm: move_page_tables by extents
Hugh Dickins authored
63 if (!pmd)
c74df32 [PATCH] mm: ptd_alloc take ptlock
Hugh Dickins authored
64 return NULL;
7be7a54 [PATCH] mm: move_page_tables by extents
Hugh Dickins authored
65
8ac1f83 thp: pte alloc trans splitting
Andrea Arcangeli authored
66 VM_BUG_ON(pmd_trans_huge(*pmd));
c74df32 [PATCH] mm: ptd_alloc take ptlock
Hugh Dickins authored
67
7be7a54 [PATCH] mm: move_page_tables by extents
Hugh Dickins authored
68 return pmd;
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
69 }
70
7be7a54 [PATCH] mm: move_page_tables by extents
Hugh Dickins authored
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,
74 unsigned long new_addr)
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
75 {
76 struct address_space *mapping = NULL;
77 struct mm_struct *mm = vma->vm_mm;
7be7a54 [PATCH] mm: move_page_tables by extents
Hugh Dickins authored
78 pte_t *old_pte, *new_pte, pte;
4c21e2f [PATCH] mm: split page table lock
Hugh Dickins authored
79 spinlock_t *old_ptl, *new_ptl;
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
80
81 if (vma->vm_file) {
82 /*
83 * Subtle point from Rajesh Venkatasubramanian: before
25d9e2d truncate: new helpers
npiggin@suse.de authored
84 * moving file-based ptes, we must lock truncate_pagecache
85 * out, since it might clean the dst vma before the src vma,
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
86 * and we propagate stale pages into the dst afterward.
87 */
88 mapping = vma->vm_file->f_mapping;
3d48ae4 mm: Convert i_mmap_lock to a mutex
Peter Zijlstra authored
89 mutex_lock(&mapping->i_mmap_mutex);
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
90 }
91
4c21e2f [PATCH] mm: split page table lock
Hugh Dickins authored
92 /*
93 * We don't have to worry about the ordering of src and dst
94 * pte locks because exclusive mmap_sem prevents deadlock.
95 */
c74df32 [PATCH] mm: ptd_alloc take ptlock
Hugh Dickins authored
96 old_pte = pte_offset_map_lock(mm, old_pmd, old_addr, &old_ptl);
ece0e2b mm: remove pte_*map_nested()
Peter Zijlstra authored
97 new_pte = pte_offset_map(new_pmd, new_addr);
4c21e2f [PATCH] mm: split page table lock
Hugh Dickins authored
98 new_ptl = pte_lockptr(mm, new_pmd);
99 if (new_ptl != old_ptl)
f20dc5f [PATCH] lockdep: annotate mm
Ingo Molnar authored
100 spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING);
6606c3e [PATCH] paravirt: lazy mmu mode hooks.patch
Zachary Amsden authored
101 arch_enter_lazy_mmu_mode();
7be7a54 [PATCH] mm: move_page_tables by extents
Hugh Dickins authored
102
103 for (; old_addr < old_end; old_pte++, old_addr += PAGE_SIZE,
104 new_pte++, new_addr += PAGE_SIZE) {
105 if (pte_none(*old_pte))
106 continue;
7b6efc2 mremap: avoid sending one IPI per page
Andrea Arcangeli authored
107 pte = ptep_get_and_clear(mm, old_addr, old_pte);
7be7a54 [PATCH] mm: move_page_tables by extents
Hugh Dickins authored
108 pte = move_pte(pte, new_vma->vm_page_prot, old_addr, new_addr);
109 set_pte_at(mm, new_addr, new_pte, pte);
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
110 }
7be7a54 [PATCH] mm: move_page_tables by extents
Hugh Dickins authored
111
6606c3e [PATCH] paravirt: lazy mmu mode hooks.patch
Zachary Amsden authored
112 arch_leave_lazy_mmu_mode();
4c21e2f [PATCH] mm: split page table lock
Hugh Dickins authored
113 if (new_ptl != old_ptl)
114 spin_unlock(new_ptl);
ece0e2b mm: remove pte_*map_nested()
Peter Zijlstra authored
115 pte_unmap(new_pte - 1);
c74df32 [PATCH] mm: ptd_alloc take ptlock
Hugh Dickins authored
116 pte_unmap_unlock(old_pte - 1, old_ptl);
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
117 if (mapping)
3d48ae4 mm: Convert i_mmap_lock to a mutex
Peter Zijlstra authored
118 mutex_unlock(&mapping->i_mmap_mutex);
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
119 }
120
7be7a54 [PATCH] mm: move_page_tables by extents
Hugh Dickins authored
121 #define LATENCY_LIMIT (64 * PAGE_SIZE)
122
b6a2fea @olliewild mm: variable length argument support
olliewild authored
123 unsigned long move_page_tables(struct vm_area_struct *vma,
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
124 unsigned long old_addr, struct vm_area_struct *new_vma,
125 unsigned long new_addr, unsigned long len)
126 {
7be7a54 [PATCH] mm: move_page_tables by extents
Hugh Dickins authored
127 unsigned long extent, next, old_end;
128 pmd_t *old_pmd, *new_pmd;
7b6efc2 mremap: avoid sending one IPI per page
Andrea Arcangeli authored
129 bool need_flush = false;
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
130
7be7a54 [PATCH] mm: move_page_tables by extents
Hugh Dickins authored
131 old_end = old_addr + len;
132 flush_cache_range(vma, old_addr, old_end);
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
133
7b6efc2 mremap: avoid sending one IPI per page
Andrea Arcangeli authored
134 mmu_notifier_invalidate_range_start(vma->vm_mm, old_addr, old_end);
135
7be7a54 [PATCH] mm: move_page_tables by extents
Hugh Dickins authored
136 for (; old_addr < old_end; old_addr += extent, new_addr += extent) {
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
137 cond_resched();
7be7a54 [PATCH] mm: move_page_tables by extents
Hugh Dickins authored
138 next = (old_addr + PMD_SIZE) & PMD_MASK;
ebed484 mremap: check for overflow using deltas
Andrea Arcangeli authored
139 /* even if next overflowed, extent below will be ok */
7be7a54 [PATCH] mm: move_page_tables by extents
Hugh Dickins authored
140 extent = next - old_addr;
ebed484 mremap: check for overflow using deltas
Andrea Arcangeli authored
141 if (extent > old_end - old_addr)
142 extent = old_end - old_addr;
7be7a54 [PATCH] mm: move_page_tables by extents
Hugh Dickins authored
143 old_pmd = get_old_pmd(vma->vm_mm, old_addr);
144 if (!old_pmd)
145 continue;
8ac1f83 thp: pte alloc trans splitting
Andrea Arcangeli authored
146 new_pmd = alloc_new_pmd(vma->vm_mm, vma, new_addr);
7be7a54 [PATCH] mm: move_page_tables by extents
Hugh Dickins authored
147 if (!new_pmd)
148 break;
37a1c49 thp: mremap support and TLB optimization
Andrea Arcangeli authored
149 if (pmd_trans_huge(*old_pmd)) {
150 int err = 0;
151 if (extent == HPAGE_PMD_SIZE)
152 err = move_huge_pmd(vma, new_vma, old_addr,
153 new_addr, old_end,
154 old_pmd, new_pmd);
155 if (err > 0) {
156 need_flush = true;
157 continue;
158 } else if (!err) {
159 split_huge_page_pmd(vma->vm_mm, old_pmd);
160 }
161 VM_BUG_ON(pmd_trans_huge(*old_pmd));
162 }
163 if (pmd_none(*new_pmd) && __pte_alloc(new_vma->vm_mm, new_vma,
164 new_pmd, new_addr))
165 break;
7be7a54 [PATCH] mm: move_page_tables by extents
Hugh Dickins authored
166 next = (new_addr + PMD_SIZE) & PMD_MASK;
167 if (extent > next - new_addr)
168 extent = next - new_addr;
169 if (extent > LATENCY_LIMIT)
170 extent = LATENCY_LIMIT;
171 move_ptes(vma, old_pmd, old_addr, old_addr + extent,
172 new_vma, new_pmd, new_addr);
7b6efc2 mremap: avoid sending one IPI per page
Andrea Arcangeli authored
173 need_flush = true;
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
174 }
7b6efc2 mremap: avoid sending one IPI per page
Andrea Arcangeli authored
175 if (likely(need_flush))
176 flush_tlb_range(vma, old_end-len, old_addr);
177
178 mmu_notifier_invalidate_range_end(vma->vm_mm, old_end-len, old_end);
7be7a54 [PATCH] mm: move_page_tables by extents
Hugh Dickins authored
179
180 return len + old_addr - old_end; /* how much done */
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
181 }
182
183 static unsigned long move_vma(struct vm_area_struct *vma,
184 unsigned long old_addr, unsigned long old_len,
185 unsigned long new_len, unsigned long new_addr)
186 {
187 struct mm_struct *mm = vma->vm_mm;
188 struct vm_area_struct *new_vma;
189 unsigned long vm_flags = vma->vm_flags;
190 unsigned long new_pgoff;
191 unsigned long moved_len;
192 unsigned long excess = 0;
365e9c8 [PATCH] mm: update_hiwaters just in time
Hugh Dickins authored
193 unsigned long hiwater_vm;
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
194 int split = 0;
7103ad3 ksm: mremap use err from ksm_madvise
Hugh Dickins authored
195 int err;
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
196
197 /*
198 * We'd prefer to avoid failure later on in do_munmap:
199 * which may split one vma into three before unmapping.
200 */
201 if (mm->map_count >= sysctl_max_map_count - 3)
202 return -ENOMEM;
203
1ff8299 ksm: prevent mremap move poisoning
Hugh Dickins authored
204 /*
205 * Advise KSM to break any KSM pages in the area to be moved:
206 * it would be confusing if they were to turn up at the new
207 * location, where they happen to coincide with different KSM
208 * pages recently unmapped. But leave vma->vm_flags as it was,
209 * so KSM can come around to merge on vma and new_vma afterwards.
210 */
7103ad3 ksm: mremap use err from ksm_madvise
Hugh Dickins authored
211 err = ksm_madvise(vma, old_addr, old_addr + old_len,
212 MADV_UNMERGEABLE, &vm_flags);
213 if (err)
214 return err;
1ff8299 ksm: prevent mremap move poisoning
Hugh Dickins authored
215
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
216 new_pgoff = vma->vm_pgoff + ((old_addr - vma->vm_start) >> PAGE_SHIFT);
217 new_vma = copy_vma(&vma, new_addr, new_len, new_pgoff);
218 if (!new_vma)
219 return -ENOMEM;
220
221 moved_len = move_page_tables(vma, old_addr, new_vma, new_addr, old_len);
222 if (moved_len < old_len) {
223 /*
224 * On error, move entries back from new area to old,
225 * which will succeed since page tables still there,
226 * and then proceed to unmap new area instead of old.
227 */
228 move_page_tables(new_vma, new_addr, vma, old_addr, moved_len);
229 vma = new_vma;
230 old_len = new_len;
231 old_addr = new_addr;
232 new_addr = -ENOMEM;
233 }
234
235 /* Conceal VM_ACCOUNT so old reservation is not undone */
236 if (vm_flags & VM_ACCOUNT) {
237 vma->vm_flags &= ~VM_ACCOUNT;
238 excess = vma->vm_end - vma->vm_start - old_len;
239 if (old_addr > vma->vm_start &&
240 old_addr + old_len < vma->vm_end)
241 split = 1;
242 }
243
7179906 [PATCH] mm acct accounting fix
Kirill Korotaev authored
244 /*
365e9c8 [PATCH] mm: update_hiwaters just in time
Hugh Dickins authored
245 * If we failed to move page tables we still do total_vm increment
246 * since do_munmap() will decrement it by old_len == new_len.
247 *
248 * Since total_vm is about to be raised artificially high for a
249 * moment, we need to restore high watermark afterwards: if stats
250 * are taken meanwhile, total_vm and hiwater_vm appear too high.
251 * If this were a serious issue, we'd add a flag to do_munmap().
7179906 [PATCH] mm acct accounting fix
Kirill Korotaev authored
252 */
365e9c8 [PATCH] mm: update_hiwaters just in time
Hugh Dickins authored
253 hiwater_vm = mm->hiwater_vm;
7179906 [PATCH] mm acct accounting fix
Kirill Korotaev authored
254 mm->total_vm += new_len >> PAGE_SHIFT;
ab50b8e [PATCH] mm: vm_stat_account unshackled
Hugh Dickins authored
255 vm_stat_account(mm, vma->vm_flags, vma->vm_file, new_len>>PAGE_SHIFT);
7179906 [PATCH] mm acct accounting fix
Kirill Korotaev authored
256
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
257 if (do_munmap(mm, old_addr, old_len) < 0) {
258 /* OOM: unable to split vma, just get accounts right */
259 vm_unacct_memory(excess >> PAGE_SHIFT);
260 excess = 0;
261 }
365e9c8 [PATCH] mm: update_hiwaters just in time
Hugh Dickins authored
262 mm->hiwater_vm = hiwater_vm;
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
263
264 /* Restore VM_ACCOUNT if one or two pieces of vma left */
265 if (excess) {
266 vma->vm_flags |= VM_ACCOUNT;
267 if (split)
268 vma->vm_next->vm_flags |= VM_ACCOUNT;
269 }
270
271 if (vm_flags & VM_LOCKED) {
272 mm->locked_vm += new_len >> PAGE_SHIFT;
273 if (new_len > old_len)
ba470de mmap: handle mlocked pages during map, remap, unmap
Rik van Riel authored
274 mlock_vma_pages_range(new_vma, new_addr + old_len,
275 new_addr + new_len);
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
276 }
277
278 return new_addr;
279 }
280
54f5de7 untangling do_mremap(), part 1
Al Viro authored
281 static struct vm_area_struct *vma_to_resize(unsigned long addr,
282 unsigned long old_len, unsigned long new_len, unsigned long *p)
283 {
284 struct mm_struct *mm = current->mm;
285 struct vm_area_struct *vma = find_vma(mm, addr);
286
287 if (!vma || vma->vm_start > addr)
288 goto Efault;
289
290 if (is_vm_hugetlb_page(vma))
291 goto Einval;
292
293 /* We can't remap across vm area boundaries */
294 if (old_len > vma->vm_end - addr)
295 goto Efault;
296
982134b @torvalds mm: avoid wrapping vm_pgoff in mremap()
torvalds authored
297 /* Need to be careful about a growing mapping */
298 if (new_len > old_len) {
299 unsigned long pgoff;
300
301 if (vma->vm_flags & (VM_DONTEXPAND | VM_PFNMAP))
54f5de7 untangling do_mremap(), part 1
Al Viro authored
302 goto Efault;
982134b @torvalds mm: avoid wrapping vm_pgoff in mremap()
torvalds authored
303 pgoff = (addr - vma->vm_start) >> PAGE_SHIFT;
304 pgoff += vma->vm_pgoff;
305 if (pgoff + (new_len >> PAGE_SHIFT) < pgoff)
306 goto Einval;
54f5de7 untangling do_mremap(), part 1
Al Viro authored
307 }
308
309 if (vma->vm_flags & VM_LOCKED) {
310 unsigned long locked, lock_limit;
311 locked = mm->locked_vm << PAGE_SHIFT;
59e99e5 mm: use rlimit helpers
Jiri Slaby authored
312 lock_limit = rlimit(RLIMIT_MEMLOCK);
54f5de7 untangling do_mremap(), part 1
Al Viro authored
313 locked += new_len - old_len;
314 if (locked > lock_limit && !capable(CAP_IPC_LOCK))
315 goto Eagain;
316 }
317
318 if (!may_expand_vm(mm, (new_len - old_len) >> PAGE_SHIFT))
319 goto Enomem;
320
321 if (vma->vm_flags & VM_ACCOUNT) {
322 unsigned long charged = (new_len - old_len) >> PAGE_SHIFT;
323 if (security_vm_enough_memory(charged))
324 goto Efault;
325 *p = charged;
326 }
327
328 return vma;
329
330 Efault: /* very odd choice for most of the cases, but... */
331 return ERR_PTR(-EFAULT);
332 Einval:
333 return ERR_PTR(-EINVAL);
334 Enomem:
335 return ERR_PTR(-ENOMEM);
336 Eagain:
337 return ERR_PTR(-EAGAIN);
338 }
339
ecc1a89 do_mremap() untangling, part 2
Al Viro authored
340 static unsigned long mremap_to(unsigned long addr,
341 unsigned long old_len, unsigned long new_addr,
342 unsigned long new_len)
343 {
344 struct mm_struct *mm = current->mm;
345 struct vm_area_struct *vma;
346 unsigned long ret = -EINVAL;
347 unsigned long charged = 0;
097eed1 fix the arch checks in MREMAP_FIXED case
Al Viro authored
348 unsigned long map_flags;
ecc1a89 do_mremap() untangling, part 2
Al Viro authored
349
350 if (new_addr & ~PAGE_MASK)
351 goto out;
352
353 if (new_len > TASK_SIZE || new_addr > TASK_SIZE - new_len)
354 goto out;
355
356 /* Check if the location we're moving into overlaps the
357 * old location at all, and fail if it does.
358 */
359 if ((new_addr <= addr) && (new_addr+new_len) > addr)
360 goto out;
361
362 if ((addr <= new_addr) && (addr+old_len) > new_addr)
363 goto out;
364
365 ret = security_file_mmap(NULL, 0, 0, 0, new_addr, 1);
366 if (ret)
367 goto out;
368
369 ret = do_munmap(mm, new_addr, new_len);
370 if (ret)
371 goto out;
372
373 if (old_len >= new_len) {
374 ret = do_munmap(mm, addr+new_len, old_len - new_len);
375 if (ret && old_len != new_len)
376 goto out;
377 old_len = new_len;
378 }
379
380 vma = vma_to_resize(addr, old_len, new_len, &charged);
381 if (IS_ERR(vma)) {
382 ret = PTR_ERR(vma);
383 goto out;
384 }
385
097eed1 fix the arch checks in MREMAP_FIXED case
Al Viro authored
386 map_flags = MAP_FIXED;
387 if (vma->vm_flags & VM_MAYSHARE)
388 map_flags |= MAP_SHARED;
9206de9 Take arch_mmap_check() into get_unmapped_area()
Al Viro authored
389
097eed1 fix the arch checks in MREMAP_FIXED case
Al Viro authored
390 ret = get_unmapped_area(vma->vm_file, new_addr, new_len, vma->vm_pgoff +
391 ((addr - vma->vm_start) >> PAGE_SHIFT),
392 map_flags);
ecc1a89 do_mremap() untangling, part 2
Al Viro authored
393 if (ret & ~PAGE_MASK)
097eed1 fix the arch checks in MREMAP_FIXED case
Al Viro authored
394 goto out1;
395
396 ret = move_vma(vma, addr, old_len, new_len, new_addr);
397 if (!(ret & ~PAGE_MASK))
398 goto out;
399 out1:
400 vm_unacct_memory(charged);
ecc1a89 do_mremap() untangling, part 2
Al Viro authored
401
402 out:
403 return ret;
404 }
405
1a0ef85 do_mremap() untangling, part 3
Al Viro authored
406 static int vma_expandable(struct vm_area_struct *vma, unsigned long delta)
407 {
f106af4 fix checks for expand-in-place mremap
Al Viro authored
408 unsigned long end = vma->vm_end + delta;
9206de9 Take arch_mmap_check() into get_unmapped_area()
Al Viro authored
409 if (end < vma->vm_end) /* overflow */
f106af4 fix checks for expand-in-place mremap
Al Viro authored
410 return 0;
9206de9 Take arch_mmap_check() into get_unmapped_area()
Al Viro authored
411 if (vma->vm_next && vma->vm_next->vm_start < end) /* intersection */
f106af4 fix checks for expand-in-place mremap
Al Viro authored
412 return 0;
413 if (get_unmapped_area(NULL, vma->vm_start, end - vma->vm_start,
414 0, MAP_FIXED) & ~PAGE_MASK)
1a0ef85 do_mremap() untangling, part 3
Al Viro authored
415 return 0;
416 return 1;
417 }
418
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
419 /*
420 * Expand (or shrink) an existing mapping, potentially moving it at the
421 * same time (controlled by the MREMAP_MAYMOVE flag and available VM space)
422 *
423 * MREMAP_FIXED option added 5-Dec-1999 by Benjamin LaHaise
424 * This option implies MREMAP_MAYMOVE.
425 */
426 unsigned long do_mremap(unsigned long addr,
427 unsigned long old_len, unsigned long new_len,
428 unsigned long flags, unsigned long new_addr)
429 {
d0de32d [PATCH] mm: do_mremap current mm
Hugh Dickins authored
430 struct mm_struct *mm = current->mm;
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
431 struct vm_area_struct *vma;
432 unsigned long ret = -EINVAL;
433 unsigned long charged = 0;
434
435 if (flags & ~(MREMAP_FIXED | MREMAP_MAYMOVE))
436 goto out;
437
438 if (addr & ~PAGE_MASK)
439 goto out;
440
441 old_len = PAGE_ALIGN(old_len);
442 new_len = PAGE_ALIGN(new_len);
443
444 /*
445 * We allow a zero old-len as a special case
446 * for DOS-emu "duplicate shm area" thing. But
447 * a zero new-len is nonsensical.
448 */
449 if (!new_len)
450 goto out;
451
452 if (flags & MREMAP_FIXED) {
ecc1a89 do_mremap() untangling, part 2
Al Viro authored
453 if (flags & MREMAP_MAYMOVE)
454 ret = mremap_to(addr, old_len, new_addr, new_len);
455 goto out;
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
456 }
457
458 /*
459 * Always allow a shrinking remap: that just unmaps
460 * the unnecessary pages..
461 * do_munmap does all the needed commit accounting
462 */
463 if (old_len >= new_len) {
d0de32d [PATCH] mm: do_mremap current mm
Hugh Dickins authored
464 ret = do_munmap(mm, addr+new_len, old_len - new_len);
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
465 if (ret && old_len != new_len)
466 goto out;
467 ret = addr;
ecc1a89 do_mremap() untangling, part 2
Al Viro authored
468 goto out;
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
469 }
470
471 /*
ecc1a89 do_mremap() untangling, part 2
Al Viro authored
472 * Ok, we need to grow..
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
473 */
54f5de7 untangling do_mremap(), part 1
Al Viro authored
474 vma = vma_to_resize(addr, old_len, new_len, &charged);
475 if (IS_ERR(vma)) {
476 ret = PTR_ERR(vma);
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
477 goto out;
119f657 [PATCH] RLIMIT_AS checking fix
akpm@osdl.org authored
478 }
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
479
480 /* old_len exactly to the end of the area..
481 */
ecc1a89 do_mremap() untangling, part 2
Al Viro authored
482 if (old_len == vma->vm_end - addr) {
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
483 /* can we just expand the current mapping? */
1a0ef85 do_mremap() untangling, part 3
Al Viro authored
484 if (vma_expandable(vma, new_len - old_len)) {
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
485 int pages = (new_len - old_len) >> PAGE_SHIFT;
486
5beb493 mm: change anon_vma linking to fix multi-process server scalability issu...
Rik van Riel authored
487 if (vma_adjust(vma, vma->vm_start, addr + new_len,
488 vma->vm_pgoff, NULL)) {
489 ret = -ENOMEM;
490 goto out;
491 }
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
492
d0de32d [PATCH] mm: do_mremap current mm
Hugh Dickins authored
493 mm->total_vm += pages;
494 vm_stat_account(mm, vma->vm_flags, vma->vm_file, pages);
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
495 if (vma->vm_flags & VM_LOCKED) {
d0de32d [PATCH] mm: do_mremap current mm
Hugh Dickins authored
496 mm->locked_vm += pages;
ba470de mmap: handle mlocked pages during map, remap, unmap
Rik van Riel authored
497 mlock_vma_pages_range(vma, addr + old_len,
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
498 addr + new_len);
499 }
500 ret = addr;
501 goto out;
502 }
503 }
504
505 /*
506 * We weren't able to just expand or shrink the area,
507 * we need to create a new one and move it..
508 */
509 ret = -ENOMEM;
510 if (flags & MREMAP_MAYMOVE) {
ecc1a89 do_mremap() untangling, part 2
Al Viro authored
511 unsigned long map_flags = 0;
512 if (vma->vm_flags & VM_MAYSHARE)
513 map_flags |= MAP_SHARED;
514
515 new_addr = get_unmapped_area(vma->vm_file, 0, new_len,
9358741 fix pgoff in "have to relocate" case of mremap()
Al Viro authored
516 vma->vm_pgoff +
517 ((addr - vma->vm_start) >> PAGE_SHIFT),
518 map_flags);
ecc1a89 do_mremap() untangling, part 2
Al Viro authored
519 if (new_addr & ~PAGE_MASK) {
520 ret = new_addr;
521 goto out;
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
522 }
ecc1a89 do_mremap() untangling, part 2
Al Viro authored
523
524 ret = security_file_mmap(NULL, 0, 0, 0, new_addr, 1);
525 if (ret)
526 goto out;
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
527 ret = move_vma(vma, addr, old_len, new_len, new_addr);
528 }
529 out:
530 if (ret & ~PAGE_MASK)
531 vm_unacct_memory(charged);
532 return ret;
533 }
534
6a6160a [CVE-2009-0029] System call wrappers part 13
Heiko Carstens authored
535 SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
536 unsigned long, new_len, unsigned long, flags,
537 unsigned long, new_addr)
1da177e Linux-2.6.12-rc2
Linus Torvalds authored
538 {
539 unsigned long ret;
540
541 down_write(&current->mm->mmap_sem);
542 ret = do_mremap(addr, old_len, new_len, flags, new_addr);
543 up_write(&current->mm->mmap_sem);
544 return ret;
545 }
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