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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>
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31SYSCALL_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 (offset_in_page(start))
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
55
56
57 down_read(&mm->mmap_sem);
58 vma = find_vma(mm, start);
59 for (;;) {
60 struct file *file;
61 loff_t fstart, fend;
62
63
64 error = -ENOMEM;
65 if (!vma)
66 goto out_unlock;
67
68 if (start < vma->vm_start) {
69 start = vma->vm_start;
70 if (start >= end)
71 goto out_unlock;
72 unmapped_error = -ENOMEM;
73 }
74
75 if ((flags & MS_INVALIDATE) &&
76 (vma->vm_flags & VM_LOCKED)) {
77 error = -EBUSY;
78 goto out_unlock;
79 }
80 file = vma->vm_file;
81 fstart = (start - vma->vm_start) +
82 ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
83 fend = fstart + (min(end, vma->vm_end) - start) - 1;
84 start = vma->vm_end;
85 if ((flags & MS_SYNC) && file &&
86 (vma->vm_flags & VM_SHARED)) {
87 get_file(file);
88 up_read(&mm->mmap_sem);
89 error = vfs_fsync_range(file, fstart, fend, 1);
90 fput(file);
91 if (error || start >= end)
92 goto out;
93 down_read(&mm->mmap_sem);
94 vma = find_vma(mm, start);
95 } else {
96 if (start >= end) {
97 error = 0;
98 goto out_unlock;
99 }
100 vma = vma->vm_next;
101 }
102 }
103out_unlock:
104 up_read(&mm->mmap_sem);
105out:
106 return error ? : unmapped_error;
107}
108