notifier-error-inject.c 2.5 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. #include <linux/module.h>
  3. #include "notifier-error-inject.h"
  4. static int debugfs_errno_set(void *data, u64 val)
  5. {
  6. *(int *)data = clamp_t(int, val, -MAX_ERRNO, 0);
  7. return 0;
  8. }
  9. static int debugfs_errno_get(void *data, u64 *val)
  10. {
  11. *val = *(int *)data;
  12. return 0;
  13. }
  14. DEFINE_SIMPLE_ATTRIBUTE(fops_errno, debugfs_errno_get, debugfs_errno_set,
  15. "%lld\n");
  16. static struct dentry *debugfs_create_errno(const char *name, umode_t mode,
  17. struct dentry *parent, int *value)
  18. {
  19. return debugfs_create_file(name, mode, parent, value, &fops_errno);
  20. }
  21. static int notifier_err_inject_callback(struct notifier_block *nb,
  22. unsigned long val, void *p)
  23. {
  24. int err = 0;
  25. struct notifier_err_inject *err_inject =
  26. container_of(nb, struct notifier_err_inject, nb);
  27. struct notifier_err_inject_action *action;
  28. for (action = err_inject->actions; action->name; action++) {
  29. if (action->val == val) {
  30. err = action->error;
  31. break;
  32. }
  33. }
  34. if (err)
  35. pr_info("Injecting error (%d) to %s\n", err, action->name);
  36. return notifier_from_errno(err);
  37. }
  38. struct dentry *notifier_err_inject_dir;
  39. EXPORT_SYMBOL_GPL(notifier_err_inject_dir);
  40. struct dentry *notifier_err_inject_init(const char *name, struct dentry *parent,
  41. struct notifier_err_inject *err_inject, int priority)
  42. {
  43. struct notifier_err_inject_action *action;
  44. umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
  45. struct dentry *dir;
  46. struct dentry *actions_dir;
  47. err_inject->nb.notifier_call = notifier_err_inject_callback;
  48. err_inject->nb.priority = priority;
  49. dir = debugfs_create_dir(name, parent);
  50. actions_dir = debugfs_create_dir("actions", dir);
  51. for (action = err_inject->actions; action->name; action++) {
  52. struct dentry *action_dir;
  53. action_dir = debugfs_create_dir(action->name, actions_dir);
  54. /*
  55. * Create debugfs r/w file containing action->error. If
  56. * notifier call chain is called with action->val, it will
  57. * fail with the error code
  58. */
  59. debugfs_create_errno("error", mode, action_dir, &action->error);
  60. }
  61. return dir;
  62. }
  63. EXPORT_SYMBOL_GPL(notifier_err_inject_init);
  64. static int __init err_inject_init(void)
  65. {
  66. notifier_err_inject_dir =
  67. debugfs_create_dir("notifier-error-inject", NULL);
  68. if (!notifier_err_inject_dir)
  69. return -ENOMEM;
  70. return 0;
  71. }
  72. static void __exit err_inject_exit(void)
  73. {
  74. debugfs_remove_recursive(notifier_err_inject_dir);
  75. }
  76. module_init(err_inject_init);
  77. module_exit(err_inject_exit);
  78. MODULE_DESCRIPTION("Notifier error injection module");
  79. MODULE_LICENSE("GPL");
  80. MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");