Eric Lee / smarc-fsl-linux-kernel

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lib/notifier-error-inject.c 2.65 KB
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81f7e3824   Eric Lee   Initial Release, ... 
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  #include <linux/module.h>
  
  #include "notifier-error-inject.h"
  
  static int debugfs_errno_set(void *data, u64 val)
  {
  	*(int *)data = clamp_t(int, val, -MAX_ERRNO, 0);
  	return 0;
  }
  
  static int debugfs_errno_get(void *data, u64 *val)
  {
  	*val = *(int *)data;
  	return 0;
  }
  
  DEFINE_SIMPLE_ATTRIBUTE(fops_errno, debugfs_errno_get, debugfs_errno_set,
  			"%lld
  ");
  
  static struct dentry *debugfs_create_errno(const char *name, umode_t mode,
  				struct dentry *parent, int *value)
  {
  	return debugfs_create_file(name, mode, parent, value, &fops_errno);
  }
  
  static int notifier_err_inject_callback(struct notifier_block *nb,
  				unsigned long val, void *p)
  {
  	int err = 0;
  	struct notifier_err_inject *err_inject =
  		container_of(nb, struct notifier_err_inject, nb);
  	struct notifier_err_inject_action *action;
  
  	for (action = err_inject->actions; action->name; action++) {
  		if (action->val == val) {
  			err = action->error;
  			break;
  		}
  	}
  	if (err)
  		pr_info("Injecting error (%d) to %s
  ", err, action->name);
  
  	return notifier_from_errno(err);
  }
  
  struct dentry *notifier_err_inject_dir;
  EXPORT_SYMBOL_GPL(notifier_err_inject_dir);
  
  struct dentry *notifier_err_inject_init(const char *name, struct dentry *parent,
  			struct notifier_err_inject *err_inject, int priority)
  {
  	struct notifier_err_inject_action *action;
  	umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
  	struct dentry *dir;
  	struct dentry *actions_dir;
  
  	err_inject->nb.notifier_call = notifier_err_inject_callback;
  	err_inject->nb.priority = priority;
  
  	dir = debugfs_create_dir(name, parent);
  	if (!dir)
  		return ERR_PTR(-ENOMEM);
  
  	actions_dir = debugfs_create_dir("actions", dir);
  	if (!actions_dir)
  		goto fail;
  
  	for (action = err_inject->actions; action->name; action++) {
  		struct dentry *action_dir;
  
  		action_dir = debugfs_create_dir(action->name, actions_dir);
  		if (!action_dir)
  			goto fail;
  
  		/*
  		 * Create debugfs r/w file containing action->error. If
  		 * notifier call chain is called with action->val, it will
  		 * fail with the error code
  		 */
  		if (!debugfs_create_errno("error", mode, action_dir,
  					&action->error))
  			goto fail;
  	}
  	return dir;
  fail:
  	debugfs_remove_recursive(dir);
  	return ERR_PTR(-ENOMEM);
  }
  EXPORT_SYMBOL_GPL(notifier_err_inject_init);
  
  static int __init err_inject_init(void)
  {
  	notifier_err_inject_dir =
  		debugfs_create_dir("notifier-error-inject", NULL);
  
  	if (!notifier_err_inject_dir)
  		return -ENOMEM;
  
  	return 0;
  }
  
  static void __exit err_inject_exit(void)
  {
  	debugfs_remove_recursive(notifier_err_inject_dir);
  }
  
  module_init(err_inject_init);
  module_exit(err_inject_exit);
  
  MODULE_DESCRIPTION("Notifier error injection module");
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");