Contents of /alx-src/tags/kernel26-2.6.12-alx-r9/mm/msync.c
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Wed Mar 4 11:03:09 2009 UTC (15 years, 6 months ago) by niro
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File size: 5671 byte(s)
Wed Mar 4 11:03:09 2009 UTC (15 years, 6 months ago) by niro
File MIME type: text/plain
File size: 5671 byte(s)
Tag kernel26-2.6.12-alx-r9
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 | } |