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// SPDX-License-Identifier: GPL-2.0-only
#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\n");
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\n", 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>");
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