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11#include <linux/fs.h>
12#include <linux/mm.h>
13#include <linux/mman.h>
14#include <linux/file.h>
15#include <linux/syscalls.h>
16#include <linux/sched.h>
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32SYSCALL_DEFINE3(msync, unsigned long, start, size_t, len, int, flags)
33{
34 unsigned long end;
35 struct mm_struct *mm = current->mm;
36 struct vm_area_struct *vma;
37 int unmapped_error = 0;
38 int error = -EINVAL;
39
40 start = untagged_addr(start);
41
42 if (flags & ~(MS_ASYNC | MS_INVALIDATE | MS_SYNC))
43 goto out;
44 if (offset_in_page(start))
45 goto out;
46 if ((flags & MS_ASYNC) && (flags & MS_SYNC))
47 goto out;
48 error = -ENOMEM;
49 len = (len + ~PAGE_MASK) & PAGE_MASK;
50 end = start + len;
51 if (end < start)
52 goto out;
53 error = 0;
54 if (end == start)
55 goto out;
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60
61
62 mmap_read_lock(mm);
63 vma = find_vma(mm, start);
64 for (;;) {
65 struct file *file;
66 loff_t fstart, fend;
67
68
69 error = -ENOMEM;
70 if (!vma)
71 goto out_unlock;
72
73 if (start < vma->vm_start) {
74 if (flags == MS_ASYNC)
75 goto out_unlock;
76 start = vma->vm_start;
77 if (start >= end)
78 goto out_unlock;
79 unmapped_error = -ENOMEM;
80 }
81
82 if ((flags & MS_INVALIDATE) &&
83 (vma->vm_flags & VM_LOCKED)) {
84 error = -EBUSY;
85 goto out_unlock;
86 }
87 file = vma->vm_file;
88 fstart = (start - vma->vm_start) +
89 ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
90 fend = fstart + (min(end, vma->vm_end) - start) - 1;
91 start = vma->vm_end;
92 if ((flags & MS_SYNC) && file &&
93 (vma->vm_flags & VM_SHARED)) {
94 get_file(file);
95 mmap_read_unlock(mm);
96 error = vfs_fsync_range(file, fstart, fend, 1);
97 fput(file);
98 if (error || start >= end)
99 goto out;
100 mmap_read_lock(mm);
101 vma = find_vma(mm, start);
102 } else {
103 if (start >= end) {
104 error = 0;
105 goto out_unlock;
106 }
107 vma = vma->vm_next;
108 }
109 }
110out_unlock:
111 mmap_read_unlock(mm);
112out:
113 return error ? : unmapped_error;
114}
115