userns: Restrict when proc and sysfs can be mounted
[linux-3.10.git] / fs / proc / mmu.c
1 /* mmu.c: mmu memory info files
2  *
3  * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
4  * Written by David Howells (dhowells@redhat.com)
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License
8  * as published by the Free Software Foundation; either version
9  * 2 of the License, or (at your option) any later version.
10  */
11 #include <linux/spinlock.h>
12 #include <linux/vmalloc.h>
13 #include <linux/highmem.h>
14 #include <asm/pgtable.h>
15 #include "internal.h"
16
17 void get_vmalloc_info(struct vmalloc_info *vmi)
18 {
19         struct vm_struct *vma;
20         unsigned long free_area_size;
21         unsigned long prev_end;
22
23         vmi->used = 0;
24
25         if (!vmlist) {
26                 vmi->largest_chunk = VMALLOC_TOTAL;
27         }
28         else {
29                 vmi->largest_chunk = 0;
30
31                 prev_end = VMALLOC_START;
32
33                 read_lock(&vmlist_lock);
34
35                 for (vma = vmlist; vma; vma = vma->next) {
36                         unsigned long addr = (unsigned long) vma->addr;
37
38                         /*
39                          * Some archs keep another range for modules in vmlist
40                          */
41                         if (addr < VMALLOC_START)
42                                 continue;
43                         if (addr >= VMALLOC_END)
44                                 break;
45
46                         vmi->used += vma->size;
47
48                         free_area_size = addr - prev_end;
49                         if (vmi->largest_chunk < free_area_size)
50                                 vmi->largest_chunk = free_area_size;
51
52                         prev_end = vma->size + addr;
53                 }
54
55                 if (VMALLOC_END - prev_end > vmi->largest_chunk)
56                         vmi->largest_chunk = VMALLOC_END - prev_end;
57
58                 read_unlock(&vmlist_lock);
59         }
60 }