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Source at commit cdde9cf73945d547acd3e96f9508c79e84ad0bf1 created 12 years 9 months ago. By Maarten ter Huurne, MMC: JZ4740: Added support for CPU frequency changing | |
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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/fs.h> |
11 | #include <linux/mm.h> |
12 | #include <linux/mman.h> |
13 | #include <linux/file.h> |
14 | #include <linux/syscalls.h> |
15 | #include <linux/sched.h> |
16 | |
17 | /* |
18 | * MS_SYNC syncs the entire file - including mappings. |
19 | * |
20 | * MS_ASYNC does not start I/O (it used to, up to 2.5.67). |
21 | * Nor does it marks the relevant pages dirty (it used to up to 2.6.17). |
22 | * Now it doesn't do anything, since dirty pages are properly tracked. |
23 | * |
24 | * The application may now run fsync() to |
25 | * write out the dirty pages and wait on the writeout and check the result. |
26 | * Or the application may run fadvise(FADV_DONTNEED) against the fd to start |
27 | * async writeout immediately. |
28 | * So by _not_ starting I/O in MS_ASYNC we provide complete flexibility to |
29 | * applications. |
30 | */ |
31 | SYSCALL_DEFINE3(msync, unsigned long, start, size_t, len, int, flags) |
32 | { |
33 | unsigned long end; |
34 | struct mm_struct *mm = current->mm; |
35 | struct vm_area_struct *vma; |
36 | int unmapped_error = 0; |
37 | int error = -EINVAL; |
38 | |
39 | if (flags & ~(MS_ASYNC | MS_INVALIDATE | MS_SYNC)) |
40 | goto out; |
41 | if (start & ~PAGE_MASK) |
42 | goto out; |
43 | if ((flags & MS_ASYNC) && (flags & MS_SYNC)) |
44 | goto out; |
45 | error = -ENOMEM; |
46 | len = (len + ~PAGE_MASK) & PAGE_MASK; |
47 | end = start + len; |
48 | if (end < start) |
49 | goto out; |
50 | error = 0; |
51 | if (end == start) |
52 | goto out; |
53 | /* |
54 | * If the interval [start,end) covers some unmapped address ranges, |
55 | * just ignore them, but return -ENOMEM at the end. |
56 | */ |
57 | down_read(&mm->mmap_sem); |
58 | vma = find_vma(mm, start); |
59 | for (;;) { |
60 | struct file *file; |
61 | |
62 | /* Still start < end. */ |
63 | error = -ENOMEM; |
64 | if (!vma) |
65 | goto out_unlock; |
66 | /* Here start < vma->vm_end. */ |
67 | if (start < vma->vm_start) { |
68 | start = vma->vm_start; |
69 | if (start >= end) |
70 | goto out_unlock; |
71 | unmapped_error = -ENOMEM; |
72 | } |
73 | /* Here vma->vm_start <= start < vma->vm_end. */ |
74 | if ((flags & MS_INVALIDATE) && |
75 | (vma->vm_flags & VM_LOCKED)) { |
76 | error = -EBUSY; |
77 | goto out_unlock; |
78 | } |
79 | file = vma->vm_file; |
80 | start = vma->vm_end; |
81 | if ((flags & MS_SYNC) && file && |
82 | (vma->vm_flags & VM_SHARED)) { |
83 | get_file(file); |
84 | up_read(&mm->mmap_sem); |
85 | error = vfs_fsync(file, 0); |
86 | fput(file); |
87 | if (error || start >= end) |
88 | goto out; |
89 | down_read(&mm->mmap_sem); |
90 | vma = find_vma(mm, start); |
91 | } else { |
92 | if (start >= end) { |
93 | error = 0; |
94 | goto out_unlock; |
95 | } |
96 | vma = vma->vm_next; |
97 | } |
98 | } |
99 | out_unlock: |
100 | up_read(&mm->mmap_sem); |
101 | out: |
102 | return error ? : unmapped_error; |
103 | } |
104 |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
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master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9