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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/mm/msync.c | |
3 | * | |
4 | * Copyright (C) 1994-1999 Linus Torvalds | |
5 | */ | |
6 | ||
7 | /* | |
8 | * The msync() system call. | |
9 | */ | |
10 | #include <linux/slab.h> | |
11 | #include <linux/pagemap.h> | |
12 | #include <linux/mm.h> | |
13 | #include <linux/mman.h> | |
14 | #include <linux/hugetlb.h> | |
9c50823e AM |
15 | #include <linux/writeback.h> |
16 | #include <linux/file.h> | |
1da177e4 LT |
17 | #include <linux/syscalls.h> |
18 | ||
19 | #include <asm/pgtable.h> | |
20 | #include <asm/tlbflush.h> | |
21 | ||
9c50823e | 22 | static unsigned long msync_pte_range(struct vm_area_struct *vma, pmd_t *pmd, |
1da177e4 LT |
23 | unsigned long addr, unsigned long end) |
24 | { | |
25 | pte_t *pte; | |
705e87c0 | 26 | spinlock_t *ptl; |
0c942a45 | 27 | int progress = 0; |
9c50823e | 28 | unsigned long ret = 0; |
1da177e4 | 29 | |
0c942a45 | 30 | again: |
705e87c0 | 31 | pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); |
1da177e4 | 32 | do { |
1da177e4 LT |
33 | struct page *page; |
34 | ||
0c942a45 HD |
35 | if (progress >= 64) { |
36 | progress = 0; | |
705e87c0 | 37 | if (need_resched() || need_lockbreak(ptl)) |
0c942a45 HD |
38 | break; |
39 | } | |
40 | progress++; | |
1da177e4 LT |
41 | if (!pte_present(*pte)) |
42 | continue; | |
b4955ce3 AK |
43 | if (!pte_maybe_dirty(*pte)) |
44 | continue; | |
6aab341e LT |
45 | page = vm_normal_page(vma, addr, *pte); |
46 | if (!page) | |
1da177e4 | 47 | continue; |
1da177e4 | 48 | if (ptep_clear_flush_dirty(vma, addr, pte) || |
9c50823e AM |
49 | page_test_and_clear_dirty(page)) |
50 | ret += set_page_dirty(page); | |
0c942a45 | 51 | progress += 3; |
1da177e4 | 52 | } while (pte++, addr += PAGE_SIZE, addr != end); |
705e87c0 HD |
53 | pte_unmap_unlock(pte - 1, ptl); |
54 | cond_resched(); | |
0c942a45 HD |
55 | if (addr != end) |
56 | goto again; | |
9c50823e | 57 | return ret; |
1da177e4 LT |
58 | } |
59 | ||
9c50823e AM |
60 | static inline unsigned long msync_pmd_range(struct vm_area_struct *vma, |
61 | pud_t *pud, unsigned long addr, unsigned long end) | |
1da177e4 LT |
62 | { |
63 | pmd_t *pmd; | |
64 | unsigned long next; | |
9c50823e | 65 | unsigned long ret = 0; |
1da177e4 LT |
66 | |
67 | pmd = pmd_offset(pud, addr); | |
68 | do { | |
69 | next = pmd_addr_end(addr, end); | |
70 | if (pmd_none_or_clear_bad(pmd)) | |
71 | continue; | |
9c50823e | 72 | ret += msync_pte_range(vma, pmd, addr, next); |
1da177e4 | 73 | } while (pmd++, addr = next, addr != end); |
9c50823e | 74 | return ret; |
1da177e4 LT |
75 | } |
76 | ||
9c50823e AM |
77 | static inline unsigned long msync_pud_range(struct vm_area_struct *vma, |
78 | pgd_t *pgd, unsigned long addr, unsigned long end) | |
1da177e4 LT |
79 | { |
80 | pud_t *pud; | |
81 | unsigned long next; | |
9c50823e | 82 | unsigned long ret = 0; |
1da177e4 LT |
83 | |
84 | pud = pud_offset(pgd, addr); | |
85 | do { | |
86 | next = pud_addr_end(addr, end); | |
87 | if (pud_none_or_clear_bad(pud)) | |
88 | continue; | |
9c50823e | 89 | ret += msync_pmd_range(vma, pud, addr, next); |
1da177e4 | 90 | } while (pud++, addr = next, addr != end); |
9c50823e | 91 | return ret; |
1da177e4 LT |
92 | } |
93 | ||
9c50823e | 94 | static unsigned long msync_page_range(struct vm_area_struct *vma, |
1da177e4 LT |
95 | unsigned long addr, unsigned long end) |
96 | { | |
1da177e4 LT |
97 | pgd_t *pgd; |
98 | unsigned long next; | |
9c50823e | 99 | unsigned long ret = 0; |
1da177e4 LT |
100 | |
101 | /* For hugepages we can't go walking the page table normally, | |
102 | * but that's ok, hugetlbfs is memory based, so we don't need | |
b5810039 | 103 | * to do anything more on an msync(). |
b5810039 | 104 | */ |
6aab341e | 105 | if (vma->vm_flags & VM_HUGETLB) |
9c50823e | 106 | return 0; |
1da177e4 LT |
107 | |
108 | BUG_ON(addr >= end); | |
705e87c0 | 109 | pgd = pgd_offset(vma->vm_mm, addr); |
1da177e4 | 110 | flush_cache_range(vma, addr, end); |
1da177e4 LT |
111 | do { |
112 | next = pgd_addr_end(addr, end); | |
113 | if (pgd_none_or_clear_bad(pgd)) | |
114 | continue; | |
9c50823e | 115 | ret += msync_pud_range(vma, pgd, addr, next); |
1da177e4 | 116 | } while (pgd++, addr = next, addr != end); |
9c50823e | 117 | return ret; |
1da177e4 LT |
118 | } |
119 | ||
1da177e4 LT |
120 | /* |
121 | * MS_SYNC syncs the entire file - including mappings. | |
122 | * | |
123 | * MS_ASYNC does not start I/O (it used to, up to 2.5.67). Instead, it just | |
124 | * marks the relevant pages dirty. The application may now run fsync() to | |
125 | * write out the dirty pages and wait on the writeout and check the result. | |
126 | * Or the application may run fadvise(FADV_DONTNEED) against the fd to start | |
127 | * async writeout immediately. | |
128 | * So my _not_ starting I/O in MS_ASYNC we provide complete flexibility to | |
129 | * applications. | |
130 | */ | |
9c50823e AM |
131 | static int msync_interval(struct vm_area_struct *vma, unsigned long addr, |
132 | unsigned long end, int flags, | |
133 | unsigned long *nr_pages_dirtied) | |
1da177e4 | 134 | { |
1da177e4 LT |
135 | struct file *file = vma->vm_file; |
136 | ||
137 | if ((flags & MS_INVALIDATE) && (vma->vm_flags & VM_LOCKED)) | |
138 | return -EBUSY; | |
139 | ||
707c21c8 | 140 | if (file && (vma->vm_flags & VM_SHARED)) |
9c50823e | 141 | *nr_pages_dirtied = msync_page_range(vma, addr, end); |
707c21c8 | 142 | return 0; |
1da177e4 LT |
143 | } |
144 | ||
145 | asmlinkage long sys_msync(unsigned long start, size_t len, int flags) | |
146 | { | |
147 | unsigned long end; | |
148 | struct vm_area_struct *vma; | |
149 | int unmapped_error, error = -EINVAL; | |
9c50823e | 150 | int done = 0; |
1da177e4 | 151 | |
1da177e4 LT |
152 | if (flags & ~(MS_ASYNC | MS_INVALIDATE | MS_SYNC)) |
153 | goto out; | |
154 | if (start & ~PAGE_MASK) | |
155 | goto out; | |
156 | if ((flags & MS_ASYNC) && (flags & MS_SYNC)) | |
157 | goto out; | |
158 | error = -ENOMEM; | |
159 | len = (len + ~PAGE_MASK) & PAGE_MASK; | |
160 | end = start + len; | |
161 | if (end < start) | |
162 | goto out; | |
163 | error = 0; | |
164 | if (end == start) | |
165 | goto out; | |
166 | /* | |
167 | * If the interval [start,end) covers some unmapped address ranges, | |
168 | * just ignore them, but return -ENOMEM at the end. | |
169 | */ | |
9c50823e AM |
170 | down_read(¤t->mm->mmap_sem); |
171 | if (flags & MS_SYNC) | |
172 | current->flags |= PF_SYNCWRITE; | |
1da177e4 LT |
173 | vma = find_vma(current->mm, start); |
174 | unmapped_error = 0; | |
9c50823e AM |
175 | do { |
176 | unsigned long nr_pages_dirtied = 0; | |
177 | struct file *file; | |
178 | ||
1da177e4 LT |
179 | /* Still start < end. */ |
180 | error = -ENOMEM; | |
181 | if (!vma) | |
9c50823e | 182 | goto out_unlock; |
1da177e4 LT |
183 | /* Here start < vma->vm_end. */ |
184 | if (start < vma->vm_start) { | |
185 | unmapped_error = -ENOMEM; | |
186 | start = vma->vm_start; | |
187 | } | |
188 | /* Here vma->vm_start <= start < vma->vm_end. */ | |
189 | if (end <= vma->vm_end) { | |
190 | if (start < end) { | |
9c50823e AM |
191 | error = msync_interval(vma, start, end, flags, |
192 | &nr_pages_dirtied); | |
1da177e4 | 193 | if (error) |
9c50823e | 194 | goto out_unlock; |
1da177e4 LT |
195 | } |
196 | error = unmapped_error; | |
9c50823e AM |
197 | done = 1; |
198 | } else { | |
199 | /* Here vma->vm_start <= start < vma->vm_end < end. */ | |
200 | error = msync_interval(vma, start, vma->vm_end, flags, | |
201 | &nr_pages_dirtied); | |
202 | if (error) | |
203 | goto out_unlock; | |
1da177e4 | 204 | } |
9c50823e | 205 | file = vma->vm_file; |
1da177e4 | 206 | start = vma->vm_end; |
9c50823e AM |
207 | if ((flags & MS_ASYNC) && file && nr_pages_dirtied) { |
208 | get_file(file); | |
209 | up_read(¤t->mm->mmap_sem); | |
210 | balance_dirty_pages_ratelimited_nr(file->f_mapping, | |
211 | nr_pages_dirtied); | |
212 | fput(file); | |
213 | down_read(¤t->mm->mmap_sem); | |
214 | vma = find_vma(current->mm, start); | |
707c21c8 AM |
215 | } else if ((flags & MS_SYNC) && file && |
216 | (vma->vm_flags & VM_SHARED)) { | |
217 | struct address_space *mapping; | |
218 | int err; | |
219 | ||
220 | get_file(file); | |
221 | up_read(¤t->mm->mmap_sem); | |
222 | mapping = file->f_mapping; | |
223 | error = filemap_fdatawrite(mapping); | |
224 | if (file->f_op && file->f_op->fsync) { | |
225 | mutex_lock(&mapping->host->i_mutex); | |
226 | err = file->f_op->fsync(file,file->f_dentry,1); | |
227 | mutex_unlock(&mapping->host->i_mutex); | |
228 | if (err && !error) | |
229 | error = err; | |
230 | } | |
231 | err = filemap_fdatawait(mapping); | |
232 | if (err && !error) | |
233 | error = err; | |
234 | fput(file); | |
235 | down_read(¤t->mm->mmap_sem); | |
236 | if (error) | |
237 | goto out_unlock; | |
238 | vma = find_vma(current->mm, start); | |
9c50823e AM |
239 | } else { |
240 | vma = vma->vm_next; | |
241 | } | |
242 | } while (!done); | |
243 | out_unlock: | |
1da177e4 | 244 | current->flags &= ~PF_SYNCWRITE; |
9c50823e AM |
245 | up_read(¤t->mm->mmap_sem); |
246 | out: | |
1da177e4 LT |
247 | return error; |
248 | } |