xref: /linux/mm/failslab.c (revision a115bc070b1fc57ab23f3972401425927b5b465c)
1 #include <linux/fault-inject.h>
2 #include <linux/gfp.h>
3 #include <linux/slab.h>
4 
5 static struct {
6 	struct fault_attr attr;
7 	u32 ignore_gfp_wait;
8 	int cache_filter;
9 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
10 	struct dentry *ignore_gfp_wait_file;
11 	struct dentry *cache_filter_file;
12 #endif
13 } failslab = {
14 	.attr = FAULT_ATTR_INITIALIZER,
15 	.ignore_gfp_wait = 1,
16 	.cache_filter = 0,
17 };
18 
19 bool should_failslab(size_t size, gfp_t gfpflags, unsigned long cache_flags)
20 {
21 	if (gfpflags & __GFP_NOFAIL)
22 		return false;
23 
24         if (failslab.ignore_gfp_wait && (gfpflags & __GFP_WAIT))
25 		return false;
26 
27 	if (failslab.cache_filter && !(cache_flags & SLAB_FAILSLAB))
28 		return false;
29 
30 	return should_fail(&failslab.attr, size);
31 }
32 
33 static int __init setup_failslab(char *str)
34 {
35 	return setup_fault_attr(&failslab.attr, str);
36 }
37 __setup("failslab=", setup_failslab);
38 
39 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
40 static int __init failslab_debugfs_init(void)
41 {
42 	mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
43 	struct dentry *dir;
44 	int err;
45 
46 	err = init_fault_attr_dentries(&failslab.attr, "failslab");
47 	if (err)
48 		return err;
49 	dir = failslab.attr.dentries.dir;
50 
51 	failslab.ignore_gfp_wait_file =
52 		debugfs_create_bool("ignore-gfp-wait", mode, dir,
53 				      &failslab.ignore_gfp_wait);
54 
55 	failslab.cache_filter_file =
56 		debugfs_create_bool("cache-filter", mode, dir,
57 				      &failslab.cache_filter);
58 
59 	if (!failslab.ignore_gfp_wait_file ||
60 	    !failslab.cache_filter_file) {
61 		err = -ENOMEM;
62 		debugfs_remove(failslab.cache_filter_file);
63 		debugfs_remove(failslab.ignore_gfp_wait_file);
64 		cleanup_fault_attr_dentries(&failslab.attr);
65 	}
66 
67 	return err;
68 }
69 
70 late_initcall(failslab_debugfs_init);
71 
72 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
73