]>
Commit | Line | Data |
---|---|---|
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> | |
15 | #include <linux/syscalls.h> | |
16 | ||
17 | #include <asm/pgtable.h> | |
18 | #include <asm/tlbflush.h> | |
19 | ||
20 | /* | |
21 | * Called with mm->page_table_lock held to protect against other | |
22 | * threads/the swapper from ripping pte's out from under us. | |
23 | */ | |
24 | ||
25 | static void sync_pte_range(struct vm_area_struct *vma, pmd_t *pmd, | |
26 | unsigned long addr, unsigned long end) | |
27 | { | |
28 | pte_t *pte; | |
29 | ||
30 | pte = pte_offset_map(pmd, addr); | |
31 | do { | |
32 | unsigned long pfn; | |
33 | struct page *page; | |
34 | ||
35 | if (!pte_present(*pte)) | |
36 | continue; | |
37 | pfn = pte_pfn(*pte); | |
38 | if (!pfn_valid(pfn)) | |
39 | continue; | |
40 | page = pfn_to_page(pfn); | |
41 | if (PageReserved(page)) | |
42 | continue; | |
43 | ||
44 | if (ptep_clear_flush_dirty(vma, addr, pte) || | |
45 | page_test_and_clear_dirty(page)) | |
46 | set_page_dirty(page); | |
47 | } while (pte++, addr += PAGE_SIZE, addr != end); | |
48 | pte_unmap(pte - 1); | |
49 | } | |
50 | ||
51 | static inline void sync_pmd_range(struct vm_area_struct *vma, pud_t *pud, | |
52 | unsigned long addr, unsigned long end) | |
53 | { | |
54 | pmd_t *pmd; | |
55 | unsigned long next; | |
56 | ||
57 | pmd = pmd_offset(pud, addr); | |
58 | do { | |
59 | next = pmd_addr_end(addr, end); | |
60 | if (pmd_none_or_clear_bad(pmd)) | |
61 | continue; | |
62 | sync_pte_range(vma, pmd, addr, next); | |
63 | } while (pmd++, addr = next, addr != end); | |
64 | } | |
65 | ||
66 | static inline void sync_pud_range(struct vm_area_struct *vma, pgd_t *pgd, | |
67 | unsigned long addr, unsigned long end) | |
68 | { | |
69 | pud_t *pud; | |
70 | unsigned long next; | |
71 | ||
72 | pud = pud_offset(pgd, addr); | |
73 | do { | |
74 | next = pud_addr_end(addr, end); | |
75 | if (pud_none_or_clear_bad(pud)) | |
76 | continue; | |
77 | sync_pmd_range(vma, pud, addr, next); | |
78 | } while (pud++, addr = next, addr != end); | |
79 | } | |
80 | ||
81 | static void sync_page_range(struct vm_area_struct *vma, | |
82 | unsigned long addr, unsigned long end) | |
83 | { | |
84 | struct mm_struct *mm = vma->vm_mm; | |
85 | pgd_t *pgd; | |
86 | unsigned long next; | |
87 | ||
88 | /* For hugepages we can't go walking the page table normally, | |
89 | * but that's ok, hugetlbfs is memory based, so we don't need | |
90 | * to do anything more on an msync() */ | |
91 | if (is_vm_hugetlb_page(vma)) | |
92 | return; | |
93 | ||
94 | BUG_ON(addr >= end); | |
95 | pgd = pgd_offset(mm, addr); | |
96 | flush_cache_range(vma, addr, end); | |
97 | spin_lock(&mm->page_table_lock); | |
98 | do { | |
99 | next = pgd_addr_end(addr, end); | |
100 | if (pgd_none_or_clear_bad(pgd)) | |
101 | continue; | |
102 | sync_pud_range(vma, pgd, addr, next); | |
103 | } while (pgd++, addr = next, addr != end); | |
104 | spin_unlock(&mm->page_table_lock); | |
105 | } | |
106 | ||
107 | #ifdef CONFIG_PREEMPT | |
108 | static inline void filemap_sync(struct vm_area_struct *vma, | |
109 | unsigned long addr, unsigned long end) | |
110 | { | |
111 | const size_t chunk = 64 * 1024; /* bytes */ | |
112 | unsigned long next; | |
113 | ||
114 | do { | |
115 | next = addr + chunk; | |
116 | if (next > end || next < addr) | |
117 | next = end; | |
118 | sync_page_range(vma, addr, next); | |
119 | cond_resched(); | |
120 | } while (addr = next, addr != end); | |
121 | } | |
122 | #else | |
123 | static inline void filemap_sync(struct vm_area_struct *vma, | |
124 | unsigned long addr, unsigned long end) | |
125 | { | |
126 | sync_page_range(vma, addr, end); | |
127 | } | |
128 | #endif | |
129 | ||
130 | /* | |
131 | * MS_SYNC syncs the entire file - including mappings. | |
132 | * | |
133 | * MS_ASYNC does not start I/O (it used to, up to 2.5.67). Instead, it just | |
134 | * marks the relevant pages dirty. The application may now run fsync() to | |
135 | * write out the dirty pages and wait on the writeout and check the result. | |
136 | * Or the application may run fadvise(FADV_DONTNEED) against the fd to start | |
137 | * async writeout immediately. | |
138 | * So my _not_ starting I/O in MS_ASYNC we provide complete flexibility to | |
139 | * applications. | |
140 | */ | |
141 | static int msync_interval(struct vm_area_struct *vma, | |
142 | unsigned long addr, unsigned long end, int flags) | |
143 | { | |
144 | int ret = 0; | |
145 | struct file *file = vma->vm_file; | |
146 | ||
147 | if ((flags & MS_INVALIDATE) && (vma->vm_flags & VM_LOCKED)) | |
148 | return -EBUSY; | |
149 | ||
150 | if (file && (vma->vm_flags & VM_SHARED)) { | |
151 | filemap_sync(vma, addr, end); | |
152 | ||
153 | if (flags & MS_SYNC) { | |
154 | struct address_space *mapping = file->f_mapping; | |
155 | int err; | |
156 | ||
157 | ret = filemap_fdatawrite(mapping); | |
158 | if (file->f_op && file->f_op->fsync) { | |
159 | /* | |
160 | * We don't take i_sem here because mmap_sem | |
161 | * is already held. | |
162 | */ | |
163 | err = file->f_op->fsync(file,file->f_dentry,1); | |
164 | if (err && !ret) | |
165 | ret = err; | |
166 | } | |
167 | err = filemap_fdatawait(mapping); | |
168 | if (!ret) | |
169 | ret = err; | |
170 | } | |
171 | } | |
172 | return ret; | |
173 | } | |
174 | ||
175 | asmlinkage long sys_msync(unsigned long start, size_t len, int flags) | |
176 | { | |
177 | unsigned long end; | |
178 | struct vm_area_struct *vma; | |
179 | int unmapped_error, error = -EINVAL; | |
180 | ||
181 | if (flags & MS_SYNC) | |
182 | current->flags |= PF_SYNCWRITE; | |
183 | ||
184 | down_read(¤t->mm->mmap_sem); | |
185 | if (flags & ~(MS_ASYNC | MS_INVALIDATE | MS_SYNC)) | |
186 | goto out; | |
187 | if (start & ~PAGE_MASK) | |
188 | goto out; | |
189 | if ((flags & MS_ASYNC) && (flags & MS_SYNC)) | |
190 | goto out; | |
191 | error = -ENOMEM; | |
192 | len = (len + ~PAGE_MASK) & PAGE_MASK; | |
193 | end = start + len; | |
194 | if (end < start) | |
195 | goto out; | |
196 | error = 0; | |
197 | if (end == start) | |
198 | goto out; | |
199 | /* | |
200 | * If the interval [start,end) covers some unmapped address ranges, | |
201 | * just ignore them, but return -ENOMEM at the end. | |
202 | */ | |
203 | vma = find_vma(current->mm, start); | |
204 | unmapped_error = 0; | |
205 | for (;;) { | |
206 | /* Still start < end. */ | |
207 | error = -ENOMEM; | |
208 | if (!vma) | |
209 | goto out; | |
210 | /* Here start < vma->vm_end. */ | |
211 | if (start < vma->vm_start) { | |
212 | unmapped_error = -ENOMEM; | |
213 | start = vma->vm_start; | |
214 | } | |
215 | /* Here vma->vm_start <= start < vma->vm_end. */ | |
216 | if (end <= vma->vm_end) { | |
217 | if (start < end) { | |
218 | error = msync_interval(vma, start, end, flags); | |
219 | if (error) | |
220 | goto out; | |
221 | } | |
222 | error = unmapped_error; | |
223 | goto out; | |
224 | } | |
225 | /* Here vma->vm_start <= start < vma->vm_end < end. */ | |
226 | error = msync_interval(vma, start, vma->vm_end, flags); | |
227 | if (error) | |
228 | goto out; | |
229 | start = vma->vm_end; | |
230 | vma = vma->vm_next; | |
231 | } | |
232 | out: | |
233 | up_read(¤t->mm->mmap_sem); | |
234 | current->flags &= ~PF_SYNCWRITE; | |
235 | return error; | |
236 | } |