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linux/lib/notifier-error-inject.c
Akinobu Mita f883c3edd2 lib/notifier-error-inject: fix error when writing -errno to debugfs file
The simple attribute files do not accept a negative value since the commit
488dac0c92 ("libfs: fix error cast of negative value in
simple_attr_write()").

This restores the previous behaviour by using newly introduced
DEFINE_SIMPLE_ATTRIBUTE_SIGNED instead of DEFINE_SIMPLE_ATTRIBUTE.

Link: https://lkml.kernel.org/r/20220919172418.45257-3-akinobu.mita@gmail.com
Fixes: 488dac0c92 ("libfs: fix error cast of negative value in simple_attr_write()")
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Reported-by: Zhao Gongyi <zhaogongyi@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Wei Yongjun <weiyongjun1@huawei.com>
Cc: Yicong Yang <yangyicong@hisilicon.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30 16:13:16 -08:00

103 lines
2.5 KiB
C

// 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_SIGNED(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);
actions_dir = debugfs_create_dir("actions", dir);
for (action = err_inject->actions; action->name; action++) {
struct dentry *action_dir;
action_dir = debugfs_create_dir(action->name, actions_dir);
/*
* Create debugfs r/w file containing action->error. If
* notifier call chain is called with action->val, it will
* fail with the error code
*/
debugfs_create_errno("error", mode, action_dir, &action->error);
}
return dir;
}
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>");