memcg: ensure list is empty at rmdir
[linux-2.6.git] / mm / hwpoison-inject.c
1 /* Inject a hwpoison memory failure on a arbitary pfn */
2 #include <linux/module.h>
3 #include <linux/debugfs.h>
4 #include <linux/kernel.h>
5 #include <linux/mm.h>
6 #include <linux/swap.h>
7 #include <linux/pagemap.h>
8 #include "internal.h"
9
10 static struct dentry *hwpoison_dir;
11
12 static int hwpoison_inject(void *data, u64 val)
13 {
14         unsigned long pfn = val;
15         struct page *p;
16         int err;
17
18         if (!capable(CAP_SYS_ADMIN))
19                 return -EPERM;
20
21         if (!hwpoison_filter_enable)
22                 goto inject;
23         if (!pfn_valid(pfn))
24                 return -ENXIO;
25
26         p = pfn_to_page(pfn);
27         /*
28          * This implies unable to support free buddy pages.
29          */
30         if (!get_page_unless_zero(p))
31                 return 0;
32
33         if (!PageLRU(p))
34                 shake_page(p, 0);
35         /*
36          * This implies unable to support non-LRU pages.
37          */
38         if (!PageLRU(p))
39                 return 0;
40
41         /*
42          * do a racy check with elevated page count, to make sure PG_hwpoison
43          * will only be set for the targeted owner (or on a free page).
44          * We temporarily take page lock for try_get_mem_cgroup_from_page().
45          * __memory_failure() will redo the check reliably inside page lock.
46          */
47         lock_page(p);
48         err = hwpoison_filter(p);
49         unlock_page(p);
50         if (err)
51                 return 0;
52
53 inject:
54         printk(KERN_INFO "Injecting memory failure at pfn %lx\n", pfn);
55         return __memory_failure(pfn, 18, MF_COUNT_INCREASED);
56 }
57
58 static int hwpoison_unpoison(void *data, u64 val)
59 {
60         if (!capable(CAP_SYS_ADMIN))
61                 return -EPERM;
62
63         return unpoison_memory(val);
64 }
65
66 DEFINE_SIMPLE_ATTRIBUTE(hwpoison_fops, NULL, hwpoison_inject, "%lli\n");
67 DEFINE_SIMPLE_ATTRIBUTE(unpoison_fops, NULL, hwpoison_unpoison, "%lli\n");
68
69 static void pfn_inject_exit(void)
70 {
71         if (hwpoison_dir)
72                 debugfs_remove_recursive(hwpoison_dir);
73 }
74
75 static int pfn_inject_init(void)
76 {
77         struct dentry *dentry;
78
79         hwpoison_dir = debugfs_create_dir("hwpoison", NULL);
80         if (hwpoison_dir == NULL)
81                 return -ENOMEM;
82
83         /*
84          * Note that the below poison/unpoison interfaces do not involve
85          * hardware status change, hence do not require hardware support.
86          * They are mainly for testing hwpoison in software level.
87          */
88         dentry = debugfs_create_file("corrupt-pfn", 0600, hwpoison_dir,
89                                           NULL, &hwpoison_fops);
90         if (!dentry)
91                 goto fail;
92
93         dentry = debugfs_create_file("unpoison-pfn", 0600, hwpoison_dir,
94                                      NULL, &unpoison_fops);
95         if (!dentry)
96                 goto fail;
97
98         dentry = debugfs_create_u32("corrupt-filter-enable", 0600,
99                                     hwpoison_dir, &hwpoison_filter_enable);
100         if (!dentry)
101                 goto fail;
102
103         dentry = debugfs_create_u32("corrupt-filter-dev-major", 0600,
104                                     hwpoison_dir, &hwpoison_filter_dev_major);
105         if (!dentry)
106                 goto fail;
107
108         dentry = debugfs_create_u32("corrupt-filter-dev-minor", 0600,
109                                     hwpoison_dir, &hwpoison_filter_dev_minor);
110         if (!dentry)
111                 goto fail;
112
113         dentry = debugfs_create_u64("corrupt-filter-flags-mask", 0600,
114                                     hwpoison_dir, &hwpoison_filter_flags_mask);
115         if (!dentry)
116                 goto fail;
117
118         dentry = debugfs_create_u64("corrupt-filter-flags-value", 0600,
119                                     hwpoison_dir, &hwpoison_filter_flags_value);
120         if (!dentry)
121                 goto fail;
122
123 #ifdef  CONFIG_CGROUP_MEM_RES_CTLR_SWAP
124         dentry = debugfs_create_u64("corrupt-filter-memcg", 0600,
125                                     hwpoison_dir, &hwpoison_filter_memcg);
126         if (!dentry)
127                 goto fail;
128 #endif
129
130         return 0;
131 fail:
132         pfn_inject_exit();
133         return -ENOMEM;
134 }
135
136 module_init(pfn_inject_init);
137 module_exit(pfn_inject_exit);
138 MODULE_LICENSE("GPL");